The Structure of Git

A git tutorial for (computer) scientists

Dylan Simon, Flatiron Institute

[github.com/dylex/git-structure-tutorial](https://github.com/dylex/git-structure-tutorial)

First, try to forget anything you know about other revision control systems, and even git itself. In fact, for the moment, let's forget about revision control.

Second, this is a workshop: follow along, try things yourself, ask questions.

Part 1: Data Structures

(Commands you'll never use again)

Git has lots of functionality, often based on other revision control systems, but at its core it's quite simple. Even though you will rarely use these core commands, it's useful to understand how they work, and thus how all the more complicated interfaces are just constructed out of these simpler ones. Also, if you get confused about what's going on, this will give you enough to get by on first principles.

git repository environment

Create a new repository in any existing directory

git init ~/myrepo
cd ~/myrepo

git-init         - Create an empty Git repository or reinitialize an existing one
Initialized empty Git repository in /home/dylan/myrepo/.git/

You can turn any directory into a git repository. You'll more often create a new one based on an existing repository using clone, as we'll see at the end. For now, we'll just start with an empty directory.

ls .git

HEAD  config  description  hooks  info  objects  refs

All this does is create a .git directory with some stuff in it. Normally you won't touch any of this stuff directly, but we'll see what some of it does. You can also have a .git directory by itself, which is called a "bare" repository and is like a backend or server only: only usable "remotely".

cat .git/config

[core]
	repositoryformatversion = 0
	filemode = true
	bare = false
	logallrefupdates = true

One of the files in this directory you might look at is config. Git config files are simple ini-type files. There is also your "global" config in ~/.gitconfig.

git config --local -l

git-config       - Get and set repository or global options
core.repositoryformatversion=0
core.filemode=true
core.bare=false
core.logallrefupdates=true

However, there is also a git command that lets you manipulate config files, so you don't have to edit them yourself.

git config -h
git help config
git help

usage: git config [<options>]

Config file location
    --global              use global config file
    --system              use system config file
    --local               use repository config file
    -f, --file <file>     use given config file
    --blob <blob-id>      read config from given blob object

Action
    --get                 get value: name [value-regex]
    --get-all             get all values: key [value-regex]
    --get-regexp          get values for regexp: name-regex [value-regex]
    --get-urlmatch        get value specific for the URL: section[.var] URL
    --replace-all         replace all matching variables: name value [value_regex]
    --add                 add a new variable: name value
    --unset               remove a variable: name [value-regex]
    --unset-all           remove all matches: name [value-regex]
    --rename-section      rename section: old-name new-name
    --remove-section      remove a section: name
    -l, --list            list all
    -e, --edit            open an editor
    --get-color           find the color configured: slot [default]
    --get-colorbool       find the color setting: slot [stdout-is-tty]

Type
    --bool                value is "true" or "false"
    --int                 value is decimal number
    --bool-or-int         value is --bool or --int
    --path                value is a path (file or directory name)

Other
    -z, --null            terminate values with NUL byte
    --name-only           show variable names only
    --includes            respect include directives on lookup
    --show-origin         show origin of config (file, standard input, blob, command line)

git-help         - Display help information about Git
GIT-CONFIG(1)                     Git Manual                     GIT-CONFIG(1)

NNAAMMEE
       git-config - Get and set repository or global options

SSYYNNOOPPSSIISS
       _g_i_t _c_o_n_f_i_g [<file-option>] [type] [--show-origin] [-z|--null] name [value [value_regex]]
       _g_i_t _c_o_n_f_i_g [<file-option>] [type] --add name value
       _g_i_t _c_o_n_f_i_g [<file-option>] [type] --replace-all name value [value_regex]
       _g_i_t _c_o_n_f_i_g [<file-option>] [type] [--show-origin] [-z|--null] --get name [value_regex]
       _g_i_t _c_o_n_f_i_g [<file-option>] [type] [--show-origin] [-z|--null] --get-all name [value_regex]
       _g_i_t _c_o_n_f_i_g [<file-option>] [type] [--show-origin] [-z|--null] [--name-only] --get-regexp name_regex [value_regex]
       _g_i_t _c_o_n_f_i_g [<file-option>] [type] [-z|--null] --get-urlmatch name URL
       _g_i_t _c_o_n_f_i_g [<file-option>] --unset name [value_regex]
       _g_i_t _c_o_n_f_i_g [<file-option>] --unset-all name [value_regex]
       _g_i_t _c_o_n_f_i_g [<file-option>] --rename-section old_name new_name
       _g_i_t _c_o_n_f_i_g [<file-option>] --remove-section name
       _g_i_t _c_o_n_f_i_g [<file-option>] [--show-origin] [-z|--null] [--name-only] -l | --list
       _g_i_t _c_o_n_f_i_g [<file-option>] --get-color name [default]
       _g_i_t _c_o_n_f_i_g [<file-option>] --get-colorbool name [stdout-is-tty]
       _g_i_t _c_o_n_f_i_g [<file-option>] -e | --edit

DDEESSCCRRIIPPTTIIOONN
       You can query/set/replace/unset options with this command. The name is
       actually the section and the key separated by a dot, and the value will
       be escaped.

       Multiple lines can be added to an option by using the ----aadddd option. If
       you want to update or unset an option which can occur on multiple
       lines, a POSIX regexp vvaalluuee__rreeggeexx needs to be given. Only the existing
       values that match the regexp are updated or unset. If you want to
       handle the lines that do nnoott match the regex, just prepend a single
       exclamation mark in front (see also the section called “EXAMPLES”).

       The type specifier can be either ----iinntt or ----bbooooll, to make _g_i_t _c_o_n_f_i_g
       ensure that the variable(s) are of the given type and convert the value
       to the canonical form (simple decimal number for int, a "true" or
       "false" string for bool), or ----ppaatthh, which does some path expansion
       (see ----ppaatthh below). If no type specifier is passed, no checks or
       transformations are performed on the value.

       When reading, the values are read from the system, global and
       repository local configuration files by default, and options ----ssyysstteemm,
       ----gglloobbaall, ----llooccaall and ----ffiillee <<ffiilleennaammee>> can be used to tell the command
       to read from only that location (see the section called “FILES”).

       When writing, the new value is written to the repository local
       configuration file by default, and options ----ssyysstteemm, ----gglloobbaall, ----ffiillee
       <<ffiilleennaammee>> can be used to tell the command to write to that location
       (you can say ----llooccaall but that is the default).

       This command will fail with non-zero status upon error. Some exit codes
       are:

       ·   The section or key is invalid (ret=1),

       ·   no section or name was provided (ret=2),

       ·   the config file is invalid (ret=3),

       ·   the config file cannot be written (ret=4),

       ·   you try to unset an option which does not exist (ret=5),

       ·   you try to unset/set an option for which multiple lines match
           (ret=5), or

       ·   you try to use an invalid regexp (ret=6).

       On success, the command returns the exit code 0.

OOPPTTIIOONNSS
       --replace-all
           Default behavior is to replace at most one line. This replaces all
           lines matching the key (and optionally the value_regex).

       --add
           Adds a new line to the option without altering any existing values.
           This is the same as providing _^_$ as the value_regex in
           ----rreeppllaaccee--aallll.

       --get
           Get the value for a given key (optionally filtered by a regex
           matching the value). Returns error code 1 if the key was not found
           and the last value if multiple key values were found.

       --get-all
           Like get, but returns all values for a multi-valued key.

       --get-regexp
           Like --get-all, but interprets the name as a regular expression and
           writes out the key names. Regular expression matching is currently
           case-sensitive and done against a canonicalized version of the key
           in which section and variable names are lowercased, but subsection
           names are not.

       --get-urlmatch name URL
           When given a two-part name section.key, the value for
           section.<url>.key whose <url> part matches the best to the given
           URL is returned (if no such key exists, the value for section.key
           is used as a fallback). When given just the section as name, do so
           for all the keys in the section and list them. Returns error code 1
           if no value is found.

       --global
           For writing options: write to global ~~//..ggiittccoonnffiigg file rather than
           the repository ..ggiitt//ccoonnffiigg, write to $$XXDDGG__CCOONNFFIIGG__HHOOMMEE//ggiitt//ccoonnffiigg
           file if this file exists and the ~~//..ggiittccoonnffiigg file doesn’t.

           For reading options: read only from global ~~//..ggiittccoonnffiigg and from
           $$XXDDGG__CCOONNFFIIGG__HHOOMMEE//ggiitt//ccoonnffiigg rather than from all available files.

           See also the section called “FILES”.

       --system
           For writing options: write to system-wide $$((pprreeffiixx))//eettcc//ggiittccoonnffiigg
           rather than the repository ..ggiitt//ccoonnffiigg.

           For reading options: read only from system-wide
           $$((pprreeffiixx))//eettcc//ggiittccoonnffiigg rather than from all available files.

           See also the section called “FILES”.

       --local
           For writing options: write to the repository ..ggiitt//ccoonnffiigg file. This
           is the default behavior.

           For reading options: read only from the repository ..ggiitt//ccoonnffiigg
           rather than from all available files.

           See also the section called “FILES”.

       -f config-file, --file config-file
           Use the given config file instead of the one specified by
           GIT_CONFIG.

       --blob blob
           Similar to ----ffiillee but use the given blob instead of a file. E.g.
           you can use _m_a_s_t_e_r_:_._g_i_t_m_o_d_u_l_e_s to read values from the file
           _._g_i_t_m_o_d_u_l_e_s in the master branch. See "SPECIFYING REVISIONS"
           section in ggiittrreevviissiioonnss(7) for a more complete list of ways to
           spell blob names.

       --remove-section
           Remove the given section from the configuration file.

       --rename-section
           Rename the given section to a new name.

       --unset
           Remove the line matching the key from config file.

       --unset-all
           Remove all lines matching the key from config file.

       -l, --list
           List all variables set in config file, along with their values.

       --bool
           _g_i_t _c_o_n_f_i_g will ensure that the output is "true" or "false"

       --int
           _g_i_t _c_o_n_f_i_g will ensure that the output is a simple decimal number.
           An optional value suffix of _k, _m, or _g in the config file will
           cause the value to be multiplied by 1024, 1048576, or 1073741824
           prior to output.

       --bool-or-int
           _g_i_t _c_o_n_f_i_g will ensure that the output matches the format of either
           --bool or --int, as described above.

       --path
           _g_i_t_-_c_o_n_f_i_g will expand leading _~ to the value of _$_H_O_M_E, and _~_u_s_e_r
           to the home directory for the specified user. This option has no
           effect when setting the value (but you can use _g_i_t _c_o_n_f_i_g _b_l_a _~_/
           from the command line to let your shell do the expansion).

       -z, --null
           For all options that output values and/or keys, always end values
           with the null character (instead of a newline). Use newline instead
           as a delimiter between key and value. This allows for secure
           parsing of the output without getting confused e.g. by values that
           contain line breaks.

       --name-only
           Output only the names of config variables for ----lliisstt or
           ----ggeett--rreeggeexxpp.

       --show-origin
           Augment the output of all queried config options with the origin
           type (file, standard input, blob, command line) and the actual
           origin (config file path, ref, or blob id if applicable).

       --get-colorbool name [stdout-is-tty]
           Find the color setting for nnaammee (e.g.  ccoolloorr..ddiiffff) and output
           "true" or "false".  ssttddoouutt--iiss--ttttyy should be either "true" or
           "false", and is taken into account when configuration says "auto".
           If ssttddoouutt--iiss--ttttyy is missing, then checks the standard output of the
           command itself, and exits with status 0 if color is to be used, or
           exits with status 1 otherwise. When the color setting for nnaammee is
           undefined, the command uses ccoolloorr..uuii as fallback.

       --get-color name [default]
           Find the color configured for nnaammee (e.g.  ccoolloorr..ddiiffff..nneeww) and
           output it as the ANSI color escape sequence to the standard output.
           The optional ddeeffaauulltt parameter is used instead, if there is no
           color configured for nnaammee.

       -e, --edit
           Opens an editor to modify the specified config file; either
           ----ssyysstteemm, ----gglloobbaall, or repository (default).

       --[no-]includes
           Respect iinncclluuddee..**  directives in config files when looking up
           values. Defaults to ooffff when a specific file is given (e.g., using
           ----ffiillee, ----gglloobbaall, etc) and oonn when searching all config files.

FFIILLEESS
       If not set explicitly with ----ffiillee, there are four files where _g_i_t
       _c_o_n_f_i_g will search for configuration options:

       $(prefix)/etc/gitconfig
           System-wide configuration file.

       $XDG_CONFIG_HOME/git/config
           Second user-specific configuration file. If $XDG_CONFIG_HOME is not
           set or empty, $$HHOOMMEE//..ccoonnffiigg//ggiitt//ccoonnffiigg will be used. Any
           single-valued variable set in this file will be overwritten by
           whatever is in ~~//..ggiittccoonnffiigg. It is a good idea not to create this
           file if you sometimes use older versions of Git, as support for
           this file was added fairly recently.

       ~/.gitconfig
           User-specific configuration file. Also called "global"
           configuration file.

       $GIT_DIR/config
           Repository specific configuration file.

       If no further options are given, all reading options will read all of
       these files that are available. If the global or the system-wide
       configuration file are not available they will be ignored. If the
       repository configuration file is not available or readable, _g_i_t _c_o_n_f_i_g
       will exit with a non-zero error code. However, in neither case will an
       error message be issued.

       The files are read in the order given above, with last value found
       taking precedence over values read earlier. When multiple values are
       taken then all values of a key from all files will be used.

       You may override individual configuration parameters when running any
       git command by using the --cc option. See ggiitt(1) for details.

       All writing options will per default write to the repository specific
       configuration file. Note that this also affects options like
       ----rreeppllaaccee--aallll and ----uunnsseett. _g_i_t _c_o_n_f_i_g wwiillll oonnllyy eevveerr cchhaannggee oonnee ffiillee aatt
       aa ttiimmee.

       You can override these rules either by command-line options or by
       environment variables. The ----gglloobbaall and the ----ssyysstteemm options will limit
       the file used to the global or system-wide file respectively. The
       GGIITT__CCOONNFFIIGG environment variable has a similar effect, but you can
       specify any filename you want.

EENNVVIIRROONNMMEENNTT
       GIT_CONFIG
           Take the configuration from the given file instead of .git/config.
           Using the "--global" option forces this to ~/.gitconfig. Using the
           "--system" option forces this to $(prefix)/etc/gitconfig.

       GIT_CONFIG_NOSYSTEM
           Whether to skip reading settings from the system-wide
           $(prefix)/etc/gitconfig file. See ggiitt(1) for details.

       See also the section called “FILES”.

EEXXAAMMPPLLEESS
       Given a .git/config like this:

           #
           # This is the config file, and
           # a '#' or ';' character indicates
           # a comment
           #

           ; core variables
           [core]
                   ; Don't trust file modes
                   filemode = false

           ; Our diff algorithm
           [diff]
                   external = /usr/local/bin/diff-wrapper
                   renames = true

           ; Proxy settings
           [core]
                   gitproxy=proxy-command for kernel.org
                   gitproxy=default-proxy ; for all the rest

           ; HTTP
           [http]
                   sslVerify
           [http "https://weak.example.com"]
                   sslVerify = false
                   cookieFile = /tmp/cookie.txt

       you can set the filemode to true with

           % git config core.filemode true

       The hypothetical proxy command entries actually have a postfix to
       discern what URL they apply to. Here is how to change the entry for
       kernel.org to "ssh".

           % git config core.gitproxy '"ssh" for kernel.org' 'for kernel.org$'

       This makes sure that only the key/value pair for kernel.org is
       replaced.

       To delete the entry for renames, do

           % git config --unset diff.renames

       If you want to delete an entry for a multivar (like core.gitproxy
       above), you have to provide a regex matching the value of exactly one
       line.

       To query the value for a given key, do

           % git config --get core.filemode

       or

           % git config core.filemode

       or, to query a multivar:

           % git config --get core.gitproxy "for kernel.org$"

       If you want to know all the values for a multivar, do:

           % git config --get-all core.gitproxy

       If you like to live dangerously, you can replace aallll core.gitproxy by a
       new one with

           % git config --replace-all core.gitproxy ssh

       However, if you really only want to replace the line for the default
       proxy, i.e. the one without a "for ..." postfix, do something like
       this:

           % git config core.gitproxy ssh '! for '

       To actually match only values with an exclamation mark, you have to

           % git config section.key value '[!]'

       To add a new proxy, without altering any of the existing ones, use

           % git config --add core.gitproxy '"proxy-command" for example.com'

       An example to use customized color from the configuration in your
       script:

           #!/bin/sh
           WS=$(git config --get-color color.diff.whitespace "blue reverse")
           RESET=$(git config --get-color "" "reset")
           echo "${WS}your whitespace color or blue reverse${RESET}"

       For URLs in hhttttppss::////wweeaakk..eexxaammppllee..ccoomm, hhttttpp..ssssllVVeerriiffyy is set to false,
       while it is set to ttrruuee for all others:

           % git config --bool --get-urlmatch http.sslverify https://good.example.com
           true
           % git config --bool --get-urlmatch http.sslverify https://weak.example.com
           false
           % git config --get-urlmatch http https://weak.example.com
           http.cookieFile /tmp/cookie.txt
           http.sslverify false

CCOONNFFIIGGUURRAATTIIOONN FFIILLEE
       The Git configuration file contains a number of variables that affect
       the Git commands' behavior. The ..ggiitt//ccoonnffiigg file in each repository is
       used to store the configuration for that repository, and
       $$HHOOMMEE//..ggiittccoonnffiigg is used to store a per-user configuration as fallback
       values for the ..ggiitt//ccoonnffiigg file. The file //eettcc//ggiittccoonnffiigg can be used to
       store a system-wide default configuration.

       The configuration variables are used by both the Git plumbing and the
       porcelains. The variables are divided into sections, wherein the fully
       qualified variable name of the variable itself is the last
       dot-separated segment and the section name is everything before the
       last dot. The variable names are case-insensitive, allow only
       alphanumeric characters and --, and must start with an alphabetic
       character. Some variables may appear multiple times; we say then that
       the variable is multivalued.

   SSyynnttaaxx
       The syntax is fairly flexible and permissive; whitespaces are mostly
       ignored. The _# and _; characters begin comments to the end of line,
       blank lines are ignored.

       The file consists of sections and variables. A section begins with the
       name of the section in square brackets and continues until the next
       section begins. Section names are case-insensitive. Only alphanumeric
       characters, -- and .. are allowed in section names. Each variable must
       belong to some section, which means that there must be a section header
       before the first setting of a variable.

       Sections can be further divided into subsections. To begin a subsection
       put its name in double quotes, separated by space from the section
       name, in the section header, like in the example below:

                   [section "subsection"]

       Subsection names are case sensitive and can contain any characters
       except newline (doublequote "" and backslash can be included by escaping
       them as \\"" and \\\\, respectively). Section headers cannot span multiple
       lines. Variables may belong directly to a section or to a given
       subsection. You can have [[sseeccttiioonn]] if you have [[sseeccttiioonn ""ssuubbsseeccttiioonn""]],
       but you don’t need to.

       There is also a deprecated [[sseeccttiioonn..ssuubbsseeccttiioonn]] syntax. With this
       syntax, the subsection name is converted to lower-case and is also
       compared case sensitively. These subsection names follow the same
       restrictions as section names.

       All the other lines (and the remainder of the line after the section
       header) are recognized as setting variables, in the form _n_a_m_e _= _v_a_l_u_e
       (or just _n_a_m_e, which is a short-hand to say that the variable is the
       boolean "true"). The variable names are case-insensitive, allow only
       alphanumeric characters and --, and must start with an alphabetic
       character.

       A line that defines a value can be continued to the next line by ending
       it with a \\; the backquote and the end-of-line are stripped. Leading
       whitespaces after _n_a_m_e _=, the remainder of the line after the first
       comment character _# or _;, and trailing whitespaces of the line are
       discarded unless they are enclosed in double quotes. Internal
       whitespaces within the value are retained verbatim.

       Inside double quotes, double quote "" and backslash \\ characters must be
       escaped: use \\"" for "" and \\\\ for \\.

       The following escape sequences (beside \\"" and \\\\) are recognized: \\nn
       for newline character (NL), \\tt for horizontal tabulation (HT, TAB) and
       \\bb for backspace (BS). Other char escape sequences (including octal
       escape sequences) are invalid.

   IInncclluuddeess
       The iinncclluuddee and iinncclluuddeeIIff sections allow you to include config
       directives from another source. These sections behave identically to
       each other with the exception that iinncclluuddeeIIff sections may be ignored if
       their condition does not evaluate to true; see "Conditional includes"
       below.

       You can include a config file from another by setting the special
       iinncclluuddee..ppaatthh (or iinncclluuddeeIIff..**..ppaatthh) variable to the name of the file to
       be included. The variable takes a pathname as its value, and is subject
       to tilde expansion. These variables can be given multiple times.

       The contents of the included file are inserted immediately, as if they
       had been found at the location of the include directive. If the value
       of the variable is a relative path, the path is considered to be
       relative to the configuration file in which the include directive was
       found. See below for examples.

   CCoonnddiittiioonnaall iinncclluuddeess
       You can include a config file from another conditionally by setting a
       iinncclluuddeeIIff..<<ccoonnddiittiioonn>>..ppaatthh variable to the name of the file to be
       included.

       The condition starts with a keyword followed by a colon and some data
       whose format and meaning depends on the keyword. Supported keywords
       are:

       ggiittddiirr
           The data that follows the keyword ggiittddiirr:: is used as a glob
           pattern. If the location of the .git directory matches the pattern,
           the include condition is met.

           The .git location may be auto-discovered, or come from $$GGIITT__DDIIRR
           environment variable. If the repository is auto discovered via a
           .git file (e.g. from submodules, or a linked worktree), the .git
           location would be the final location where the .git directory is,
           not where the .git file is.

           The pattern can contain standard globbing wildcards and two
           additional ones, ****// and //****, that can match multiple path
           components. Please refer to ggiittiiggnnoorree(5) for details. For
           convenience:

           ·   If the pattern starts with ~~//, ~~ will be substituted with the
               content of the environment variable HHOOMMEE.

           ·   If the pattern starts with ..//, it is replaced with the
               directory containing the current config file.

           ·   If the pattern does not start with either ~~//, ..// or //, ****// will
               be automatically prepended. For example, the pattern ffoooo//bbaarr
               becomes ****//ffoooo//bbaarr and would match //aannyy//ppaatthh//ttoo//ffoooo//bbaarr.

           ·   If the pattern ends with //, **** will be automatically added. For
               example, the pattern ffoooo// becomes ffoooo//****. In other words, it
               matches "foo" and everything inside, recursively.

       ggiittddiirr//ii
           This is the same as ggiittddiirr except that matching is done
           case-insensitively (e.g. on case-insensitive file sytems)

       A few more notes on matching via ggiittddiirr and ggiittddiirr//ii:

       ·   Symlinks in $$GGIITT__DDIIRR are not resolved before matching.

       ·   Note that "../" is not special and will match literally, which is
           unlikely what you want.

   EExxaammppllee
           # Core variables
           [core]
                   ; Don't trust file modes
                   filemode = false

           # Our diff algorithm
           [diff]
                   external = /usr/local/bin/diff-wrapper
                   renames = true

           [branch "devel"]
                   remote = origin
                   merge = refs/heads/devel

           # Proxy settings
           [core]
                   gitProxy="ssh" for "kernel.org"
                   gitProxy=default-proxy ; for the rest

           [include]
                   path = /path/to/foo.inc ; include by absolute path
                   path = foo.inc ; find "foo.inc" relative to the current file
                   path = ~/foo.inc ; find "foo.inc" in your `$HOME` directory

           ; include if $GIT_DIR is /path/to/foo/.git
           [includeIf "gitdir:/path/to/foo/.git"]
                   path = /path/to/foo.inc

           ; include for all repositories inside /path/to/group
           [includeIf "gitdir:/path/to/group/"]
                   path = /path/to/foo.inc

           ; include for all repositories inside $HOME/to/group
           [includeIf "gitdir:~/to/group/"]
                   path = /path/to/foo.inc

           ; relative paths are always relative to the including
           ; file (if the condition is true); their location is not
           ; affected by the condition
           [includeIf "gitdir:/path/to/group/"]
                   path = foo.inc

   VVaalluueess
       Values of many variables are treated as a simple string, but there are
       variables that take values of specific types and there are rules as to
       how to spell them.

       boolean
           When a variable is said to take a boolean value, many synonyms are
           accepted for _t_r_u_e and _f_a_l_s_e; these are all case-insensitive.

           true
               Boolean true can be spelled as yyeess, oonn, ttrruuee, or 11. Also, a
               variable defined without == <<vvaalluuee>> is taken as true.

           false
               Boolean false can be spelled as nnoo, ooffff, ffaallssee, or 00.

               When converting value to the canonical form using ----bbooooll type
               specifier; _g_i_t _c_o_n_f_i_g will ensure that the output is "true" or
               "false" (spelled in lowercase).

       integer
           The value for many variables that specify various sizes can be
           suffixed with kk, MM,... to mean "scale the number by 1024", "by
           1024x1024", etc.

       color
           The value for a variable that takes a color is a list of colors (at
           most two, one for foreground and one for background) and attributes
           (as many as you want), separated by spaces.

           The basic colors accepted are nnoorrmmaall, bbllaacckk, rreedd, ggrreeeenn, yyeellllooww,
           bblluuee, mmaaggeennttaa, ccyyaann and wwhhiittee. The first color given is the
           foreground; the second is the background.

           Colors may also be given as numbers between 0 and 255; these use
           ANSI 256-color mode (but note that not all terminals may support
           this). If your terminal supports it, you may also specify 24-bit
           RGB values as hex, like ##ffff00aabb33.

           The accepted attributes are bboolldd, ddiimm, uull, bblliinnkk, rreevveerrssee, iittaalliicc,
           and ssttrriikkee (for crossed-out or "strikethrough" letters). The
           position of any attributes with respect to the colors (before,
           after, or in between), doesn’t matter. Specific attributes may be
           turned off by prefixing them with nnoo or nnoo-- (e.g., nnoorreevveerrssee,
           nnoo--uull, etc).

           An empty color string produces no color effect at all. This can be
           used to avoid coloring specific elements without disabling color
           entirely.

           For git’s pre-defined color slots, the attributes are meant to be
           reset at the beginning of each item in the colored output. So
           setting ccoolloorr..ddeeccoorraattee..bbrraanncchh to bbllaacckk will paint that branch name
           in a plain bbllaacckk, even if the previous thing on the same output
           line (e.g. opening parenthesis before the list of branch names in
           lloogg ----ddeeccoorraattee output) is set to be painted with bboolldd or some other
           attribute. However, custom log formats may do more complicated and
           layered coloring, and the negated forms may be useful there.

       pathname
           A variable that takes a pathname value can be given a string that
           begins with "~~//" or "~~uusseerr//", and the usual tilde expansion happens
           to such a string: ~~// is expanded to the value of $$HHOOMMEE, and ~~uusseerr//
           to the specified user’s home directory.

   VVaarriiaabblleess
       Note that this list is non-comprehensive and not necessarily complete.
       For command-specific variables, you will find a more detailed
       description in the appropriate manual page.

       Other git-related tools may and do use their own variables. When
       inventing new variables for use in your own tool, make sure their names
       do not conflict with those that are used by Git itself and other
       popular tools, and describe them in your documentation.

       advice.*
           These variables control various optional help messages designed to
           aid new users. All _a_d_v_i_c_e_._*  variables default to _t_r_u_e, and you can
           tell Git that you do not need help by setting these to _f_a_l_s_e:

           pushUpdateRejected
               Set this variable to _f_a_l_s_e if you want to disable
               _p_u_s_h_N_o_n_F_F_C_u_r_r_e_n_t, _p_u_s_h_N_o_n_F_F_M_a_t_c_h_i_n_g, _p_u_s_h_A_l_r_e_a_d_y_E_x_i_s_t_s,
               _p_u_s_h_F_e_t_c_h_F_i_r_s_t, and _p_u_s_h_N_e_e_d_s_F_o_r_c_e simultaneously.

           pushNonFFCurrent
               Advice shown when ggiitt--ppuusshh(1) fails due to a non-fast-forward
               update to the current branch.

           pushNonFFMatching
               Advice shown when you ran ggiitt--ppuusshh(1) and pushed _m_a_t_c_h_i_n_g _r_e_f_s
               explicitly (i.e. you used _:, or specified a refspec that isn’t
               your current branch) and it resulted in a non-fast-forward
               error.

           pushAlreadyExists
               Shown when ggiitt--ppuusshh(1) rejects an update that does not qualify
               for fast-forwarding (e.g., a tag.)

           pushFetchFirst
               Shown when ggiitt--ppuusshh(1) rejects an update that tries to
               overwrite a remote ref that points at an object we do not have.

           pushNeedsForce
               Shown when ggiitt--ppuusshh(1) rejects an update that tries to
               overwrite a remote ref that points at an object that is not a
               commit-ish, or make the remote ref point at an object that is
               not a commit-ish.

           statusHints
               Show directions on how to proceed from the current state in the
               output of ggiitt--ssttaattuuss(1), in the template shown when writing
               commit messages in ggiitt--ccoommmmiitt(1), and in the help message shown
               by ggiitt--cchheecckkoouutt(1) when switching branch.

           statusUoption
               Advise to consider using the --uu option to ggiitt--ssttaattuuss(1) when
               the command takes more than 2 seconds to enumerate untracked
               files.

           commitBeforeMerge
               Advice shown when ggiitt--mmeerrggee(1) refuses to merge to avoid
               overwriting local changes.

           resolveConflict
               Advice shown by various commands when conflicts prevent the
               operation from being performed.

           implicitIdentity
               Advice on how to set your identity configuration when your
               information is guessed from the system username and domain
               name.

           detachedHead
               Advice shown when you used ggiitt--cchheecckkoouutt(1) to move to the
               detach HEAD state, to instruct how to create a local branch
               after the fact.

           amWorkDir
               Advice that shows the location of the patch file when ggiitt--aamm(1)
               fails to apply it.

           rmHints
               In case of failure in the output of ggiitt--rrmm(1), show directions
               on how to proceed from the current state.

       core.fileMode
           Tells Git if the executable bit of files in the working tree is to
           be honored.

           Some filesystems lose the executable bit when a file that is marked
           as executable is checked out, or checks out a non-executable file
           with executable bit on.  ggiitt--cclloonnee(1) or ggiitt--iinniitt(1) probe the
           filesystem to see if it handles the executable bit correctly and
           this variable is automatically set as necessary.

           A repository, however, may be on a filesystem that handles the
           filemode correctly, and this variable is set to _t_r_u_e when created,
           but later may be made accessible from another environment that
           loses the filemode (e.g. exporting ext4 via CIFS mount, visiting a
           Cygwin created repository with Git for Windows or Eclipse). In such
           a case it may be necessary to set this variable to _f_a_l_s_e. See ggiitt--
           uuppddaattee--iinnddeexx(1).

           The default is true (when core.filemode is not specified in the
           config file).

       core.hideDotFiles
           (Windows-only) If true, mark newly-created directories and files
           whose name starts with a dot as hidden. If _d_o_t_G_i_t_O_n_l_y, only the
           ..ggiitt// directory is hidden, but no other files starting with a dot.
           The default mode is _d_o_t_G_i_t_O_n_l_y.

       core.ignoreCase
           If true, this option enables various workarounds to enable Git to
           work better on filesystems that are not case sensitive, like FAT.
           For example, if a directory listing finds "makefile" when Git
           expects "Makefile", Git will assume it is really the same file, and
           continue to remember it as "Makefile".

           The default is false, except ggiitt--cclloonnee(1) or ggiitt--iinniitt(1) will probe
           and set core.ignoreCase true if appropriate when the repository is
           created.

       core.precomposeUnicode
           This option is only used by Mac OS implementation of Git. When
           core.precomposeUnicode=true, Git reverts the unicode decomposition
           of filenames done by Mac OS. This is useful when sharing a
           repository between Mac OS and Linux or Windows. (Git for Windows
           1.7.10 or higher is needed, or Git under cygwin 1.7). When false,
           file names are handled fully transparent by Git, which is backward
           compatible with older versions of Git.

       core.protectHFS
           If set to true, do not allow checkout of paths that would be
           considered equivalent to ..ggiitt on an HFS+ filesystem. Defaults to
           ttrruuee on Mac OS, and ffaallssee elsewhere.

       core.protectNTFS
           If set to true, do not allow checkout of paths that would cause
           problems with the NTFS filesystem, e.g. conflict with 8.3 "short"
           names. Defaults to ttrruuee on Windows, and ffaallssee elsewhere.

       core.trustctime
           If false, the ctime differences between the index and the working
           tree are ignored; useful when the inode change time is regularly
           modified by something outside Git (file system crawlers and some
           backup systems). See ggiitt--uuppddaattee--iinnddeexx(1). True by default.

       core.splitIndex
           If true, the split-index feature of the index will be used. See
           ggiitt--uuppddaattee--iinnddeexx(1). False by default.

       core.untrackedCache
           Determines what to do about the untracked cache feature of the
           index. It will be kept, if this variable is unset or set to kkeeeepp.
           It will automatically be added if set to ttrruuee. And it will
           automatically be removed, if set to ffaallssee. Before setting it to
           ttrruuee, you should check that mtime is working properly on your
           system. See ggiitt--uuppddaattee--iinnddeexx(1).  kkeeeepp by default.

       core.checkStat
           Determines which stat fields to match between the index and work
           tree. The user can set this to _d_e_f_a_u_l_t or _m_i_n_i_m_a_l. Default (or
           explicitly _d_e_f_a_u_l_t), is to check all fields, including the
           sub-second part of mtime and ctime.

       core.quotePath
           Commands that output paths (e.g.  _l_s_-_f_i_l_e_s, _d_i_f_f), will quote
           "unusual" characters in the pathname by enclosing the pathname in
           double-quotes and escaping those characters with backslashes in the
           same way C escapes control characters (e.g.  \\tt for TAB, \\nn for LF,
           \\\\ for backslash) or bytes with values larger than 0x80 (e.g. octal
           \\330022\\226655 for "micro" in UTF-8). If this variable is set to false,
           bytes higher than 0x80 are not considered "unusual" any more.
           Double-quotes, backslash and control characters are always escaped
           regardless of the setting of this variable. A simple space
           character is not considered "unusual". Many commands can output
           pathnames completely verbatim using the --zz option. The default
           value is true.

       core.eol
           Sets the line ending type to use in the working directory for files
           that have the tteexxtt property set when core.autocrlf is false.
           Alternatives are _l_f, _c_r_l_f and _n_a_t_i_v_e, which uses the platform’s
           native line ending. The default value is nnaattiivvee. See
           ggiittaattttrriibbuutteess(5) for more information on end-of-line conversion.

       core.safecrlf
           If true, makes Git check if converting CCRRLLFF is reversible when
           end-of-line conversion is active. Git will verify if a command
           modifies a file in the work tree either directly or indirectly. For
           example, committing a file followed by checking out the same file
           should yield the original file in the work tree. If this is not the
           case for the current setting of ccoorree..aauuttooccrrllff, Git will reject the
           file. The variable can be set to "warn", in which case Git will
           only warn about an irreversible conversion but continue the
           operation.

           CRLF conversion bears a slight chance of corrupting data. When it
           is enabled, Git will convert CRLF to LF during commit and LF to
           CRLF during checkout. A file that contains a mixture of LF and CRLF
           before the commit cannot be recreated by Git. For text files this
           is the right thing to do: it corrects line endings such that we
           have only LF line endings in the repository. But for binary files
           that are accidentally classified as text the conversion can corrupt
           data.

           If you recognize such corruption early you can easily fix it by
           setting the conversion type explicitly in .gitattributes. Right
           after committing you still have the original file in your work tree
           and this file is not yet corrupted. You can explicitly tell Git
           that this file is binary and Git will handle the file
           appropriately.

           Unfortunately, the desired effect of cleaning up text files with
           mixed line endings and the undesired effect of corrupting binary
           files cannot be distinguished. In both cases CRLFs are removed in
           an irreversible way. For text files this is the right thing to do
           because CRLFs are line endings, while for binary files converting
           CRLFs corrupts data.

           Note, this safety check does not mean that a checkout will generate
           a file identical to the original file for a different setting of
           ccoorree..eeooll and ccoorree..aauuttooccrrllff, but only for the current one. For
           example, a text file with LLFF would be accepted with ccoorree..eeooll==llff and
           could later be checked out with ccoorree..eeooll==ccrrllff, in which case the
           resulting file would contain CCRRLLFF, although the original file
           contained LLFF. However, in both work trees the line endings would be
           consistent, that is either all LLFF or all CCRRLLFF, but never mixed. A
           file with mixed line endings would be reported by the ccoorree..ssaaffeeccrrllff
           mechanism.

       core.autocrlf
           Setting this variable to "true" is the same as setting the tteexxtt
           attribute to "auto" on all files and core.eol to "crlf". Set to
           true if you want to have CCRRLLFF line endings in your working
           directory and the repository has LF line endings. This variable can
           be set to _i_n_p_u_t, in which case no output conversion is performed.

       core.symlinks
           If false, symbolic links are checked out as small plain files that
           contain the link text.  ggiitt--uuppddaattee--iinnddeexx(1) and ggiitt--aadddd(1) will not
           change the recorded type to regular file. Useful on filesystems
           like FAT that do not support symbolic links.

           The default is true, except ggiitt--cclloonnee(1) or ggiitt--iinniitt(1) will probe
           and set core.symlinks false if appropriate when the repository is
           created.

       core.gitProxy
           A "proxy command" to execute (as _c_o_m_m_a_n_d _h_o_s_t _p_o_r_t) instead of
           establishing direct connection to the remote server when using the
           Git protocol for fetching. If the variable value is in the "COMMAND
           for DOMAIN" format, the command is applied only on hostnames ending
           with the specified domain string. This variable may be set multiple
           times and is matched in the given order; the first match wins.

           Can be overridden by the GGIITT__PPRROOXXYY__CCOOMMMMAANNDD environment variable
           (which always applies universally, without the special "for"
           handling).

           The special string nnoonnee can be used as the proxy command to specify
           that no proxy be used for a given domain pattern. This is useful
           for excluding servers inside a firewall from proxy use, while
           defaulting to a common proxy for external domains.

       core.sshCommand
           If this variable is set, ggiitt ffeettcchh and ggiitt ppuusshh will use the
           specified command instead of sssshh when they need to connect to a
           remote system. The command is in the same form as the
           GGIITT__SSSSHH__CCOOMMMMAANNDD environment variable and is overridden when the
           environment variable is set.

       core.ignoreStat
           If true, Git will avoid using lstat() calls to detect if files have
           changed by setting the "assume-unchanged" bit for those tracked
           files which it has updated identically in both the index and
           working tree.

           When files are modified outside of Git, the user will need to stage
           the modified files explicitly (e.g. see _E_x_a_m_p_l_e_s section in ggiitt--
           uuppddaattee--iinnddeexx(1)). Git will not normally detect changes to those
           files.

           This is useful on systems where lstat() calls are very slow, such
           as CIFS/Microsoft Windows.

           False by default.

       core.preferSymlinkRefs
           Instead of the default "symref" format for HEAD and other symbolic
           reference files, use symbolic links. This is sometimes needed to
           work with old scripts that expect HEAD to be a symbolic link.

       core.bare
           If true this repository is assumed to be _b_a_r_e and has no working
           directory associated with it. If this is the case a number of
           commands that require a working directory will be disabled, such as
           ggiitt--aadddd(1) or ggiitt--mmeerrggee(1).

           This setting is automatically guessed by ggiitt--cclloonnee(1) or ggiitt--
           iinniitt(1) when the repository was created. By default a repository
           that ends in "/.git" is assumed to be not bare (bare = false),
           while all other repositories are assumed to be bare (bare = true).

       core.worktree
           Set the path to the root of the working tree. If GGIITT__CCOOMMMMOONN__DDIIRR
           environment variable is set, core.worktree is ignored and not used
           for determining the root of working tree. This can be overridden by
           the GGIITT__WWOORRKK__TTRREEEE environment variable and the ----wwoorrkk--ttrreeee
           command-line option. The value can be an absolute path or relative
           to the path to the .git directory, which is either specified by
           --git-dir or GIT_DIR, or automatically discovered. If --git-dir or
           GIT_DIR is specified but none of --work-tree, GIT_WORK_TREE and
           core.worktree is specified, the current working directory is
           regarded as the top level of your working tree.

           Note that this variable is honored even when set in a configuration
           file in a ".git" subdirectory of a directory and its value differs
           from the latter directory (e.g. "/path/to/.git/config" has
           core.worktree set to "/different/path"), which is most likely a
           misconfiguration. Running Git commands in the "/path/to" directory
           will still use "/different/path" as the root of the work tree and
           can cause confusion unless you know what you are doing (e.g. you
           are creating a read-only snapshot of the same index to a location
           different from the repository’s usual working tree).

       core.logAllRefUpdates
           Enable the reflog. Updates to a ref <ref> is logged to the file
           "$$GGIITT__DDIIRR//llooggss//<<rreeff>>", by appending the new and old SHA-1, the
           date/time and the reason of the update, but only when the file
           exists. If this configuration variable is set to ttrruuee, missing
           "$$GGIITT__DDIIRR//llooggss//<<rreeff>>" file is automatically created for branch
           heads (i.e. under rreeffss//hheeaaddss//), remote refs (i.e. under
           rreeffss//rreemmootteess//), note refs (i.e. under rreeffss//nnootteess//), and the
           symbolic ref HHEEAADD. If it is set to aallwwaayyss, then a missing reflog is
           automatically created for any ref under rreeffss//.

           This information can be used to determine what commit was the tip
           of a branch "2 days ago".

           This value is true by default in a repository that has a working
           directory associated with it, and false by default in a bare
           repository.

       core.repositoryFormatVersion
           Internal variable identifying the repository format and layout
           version.

       core.sharedRepository
           When _g_r_o_u_p (or _t_r_u_e), the repository is made shareable between
           several users in a group (making sure all the files and objects are
           group-writable). When _a_l_l (or _w_o_r_l_d or _e_v_e_r_y_b_o_d_y), the repository
           will be readable by all users, additionally to being
           group-shareable. When _u_m_a_s_k (or _f_a_l_s_e), Git will use permissions
           reported by umask(2). When _0_x_x_x, where _0_x_x_x is an octal number,
           files in the repository will have this mode value.  _0_x_x_x will
           override user’s umask value (whereas the other options will only
           override requested parts of the user’s umask value). Examples: _0_6_6_0
           will make the repo read/write-able for the owner and group, but
           inaccessible to others (equivalent to _g_r_o_u_p unless umask is e.g.
           _0_0_2_2).  _0_6_4_0 is a repository that is group-readable but not
           group-writable. See ggiitt--iinniitt(1). False by default.

       core.warnAmbiguousRefs
           If true, Git will warn you if the ref name you passed it is
           ambiguous and might match multiple refs in the repository. True by
           default.

       core.compression
           An integer -1..9, indicating a default compression level. -1 is the
           zlib default. 0 means no compression, and 1..9 are various
           speed/size tradeoffs, 9 being slowest. If set, this provides a
           default to other compression variables, such as
           ccoorree..lloooosseeCCoommpprreessssiioonn and ppaacckk..ccoommpprreessssiioonn.

       core.looseCompression
           An integer -1..9, indicating the compression level for objects that
           are not in a pack file. -1 is the zlib default. 0 means no
           compression, and 1..9 are various speed/size tradeoffs, 9 being
           slowest. If not set, defaults to core.compression. If that is not
           set, defaults to 1 (best speed).

       core.packedGitWindowSize
           Number of bytes of a pack file to map into memory in a single
           mapping operation. Larger window sizes may allow your system to
           process a smaller number of large pack files more quickly. Smaller
           window sizes will negatively affect performance due to increased
           calls to the operating system’s memory manager, but may improve
           performance when accessing a large number of large pack files.

           Default is 1 MiB if NO_MMAP was set at compile time, otherwise 32
           MiB on 32 bit platforms and 1 GiB on 64 bit platforms. This should
           be reasonable for all users/operating systems. You probably do not
           need to adjust this value.

           Common unit suffixes of _k, _m, or _g are supported.

       core.packedGitLimit
           Maximum number of bytes to map simultaneously into memory from pack
           files. If Git needs to access more than this many bytes at once to
           complete an operation it will unmap existing regions to reclaim
           virtual address space within the process.

           Default is 256 MiB on 32 bit platforms and 8 GiB on 64 bit
           platforms. This should be reasonable for all users/operating
           systems, except on the largest projects. You probably do not need
           to adjust this value.

           Common unit suffixes of _k, _m, or _g are supported.

       core.deltaBaseCacheLimit
           Maximum number of bytes to reserve for caching base objects that
           may be referenced by multiple deltified objects. By storing the
           entire decompressed base objects in a cache Git is able to avoid
           unpacking and decompressing frequently used base objects multiple
           times.

           Default is 96 MiB on all platforms. This should be reasonable for
           all users/operating systems, except on the largest projects. You
           probably do not need to adjust this value.

           Common unit suffixes of _k, _m, or _g are supported.

       core.bigFileThreshold
           Files larger than this size are stored deflated, without attempting
           delta compression. Storing large files without delta compression
           avoids excessive memory usage, at the slight expense of increased
           disk usage. Additionally files larger than this size are always
           treated as binary.

           Default is 512 MiB on all platforms. This should be reasonable for
           most projects as source code and other text files can still be
           delta compressed, but larger binary media files won’t be.

           Common unit suffixes of _k, _m, or _g are supported.

       core.excludesFile
           Specifies the pathname to the file that contains patterns to
           describe paths that are not meant to be tracked, in addition to
           _._g_i_t_i_g_n_o_r_e (per-directory) and _._g_i_t_/_i_n_f_o_/_e_x_c_l_u_d_e. Defaults to
           $$XXDDGG__CCOONNFFIIGG__HHOOMMEE//ggiitt//iiggnnoorree. If $$XXDDGG__CCOONNFFIIGG__HHOOMMEE is either not set
           or empty, $$HHOOMMEE//..ccoonnffiigg//ggiitt//iiggnnoorree is used instead. See
           ggiittiiggnnoorree(5).

       core.askPass
           Some commands (e.g. svn and http interfaces) that interactively ask
           for a password can be told to use an external program given via the
           value of this variable. Can be overridden by the GGIITT__AASSKKPPAASSSS
           environment variable. If not set, fall back to the value of the
           SSSSHH__AASSKKPPAASSSS environment variable or, failing that, a simple
           password prompt. The external program shall be given a suitable
           prompt as command-line argument and write the password on its
           STDOUT.

       core.attributesFile
           In addition to _._g_i_t_a_t_t_r_i_b_u_t_e_s (per-directory) and
           _._g_i_t_/_i_n_f_o_/_a_t_t_r_i_b_u_t_e_s, Git looks into this file for attributes (see
           ggiittaattttrriibbuutteess(5)). Path expansions are made the same way as for
           ccoorree..eexxcclluuddeessFFiillee. Its default value is
           $$XXDDGG__CCOONNFFIIGG__HHOOMMEE//ggiitt//aattttrriibbuutteess. If $$XXDDGG__CCOONNFFIIGG__HHOOMMEE is either not
           set or empty, $$HHOOMMEE//..ccoonnffiigg//ggiitt//aattttrriibbuutteess is used instead.

       core.hooksPath
           By default Git will look for your hooks in the _$_G_I_T___D_I_R_/_h_o_o_k_s
           directory. Set this to different path, e.g.  _/_e_t_c_/_g_i_t_/_h_o_o_k_s, and
           Git will try to find your hooks in that directory, e.g.
           _/_e_t_c_/_g_i_t_/_h_o_o_k_s_/_p_r_e_-_r_e_c_e_i_v_e instead of in
           _$_G_I_T___D_I_R_/_h_o_o_k_s_/_p_r_e_-_r_e_c_e_i_v_e.

           The path can be either absolute or relative. A relative path is
           taken as relative to the directory where the hooks are run (see the
           "DESCRIPTION" section of ggiitthhooookkss(5)).

           This configuration variable is useful in cases where you’d like to
           centrally configure your Git hooks instead of configuring them on a
           per-repository basis, or as a more flexible and centralized
           alternative to having an iinniitt..tteemmppllaatteeDDiirr where you’ve changed
           default hooks.

       core.editor
           Commands such as ccoommmmiitt and ttaagg that let you edit messages by
           launching an editor use the value of this variable when it is set,
           and the environment variable GGIITT__EEDDIITTOORR is not set. See ggiitt--vvaarr(1).

       core.commentChar
           Commands such as ccoommmmiitt and ttaagg that let you edit messages consider
           a line that begins with this character commented, and removes them
           after the editor returns (default _#).

           If set to "auto", ggiitt--ccoommmmiitt would select a character that is not
           the beginning character of any line in existing commit messages.

       core.packedRefsTimeout
           The length of time, in milliseconds, to retry when trying to lock
           the ppaacckkeedd--rreeffss file. Value 0 means not to retry at all; -1 means
           to try indefinitely. Default is 1000 (i.e., retry for 1 second).

       sequence.editor
           Text editor used by ggiitt rreebbaassee --ii for editing the rebase
           instruction file. The value is meant to be interpreted by the shell
           when it is used. It can be overridden by the GGIITT__SSEEQQUUEENNCCEE__EEDDIITTOORR
           environment variable. When not configured the default commit
           message editor is used instead.

       core.pager
           Text viewer for use by Git commands (e.g., _l_e_s_s). The value is
           meant to be interpreted by the shell. The order of preference is
           the $$GGIITT__PPAAGGEERR environment variable, then ccoorree..ppaaggeerr configuration,
           then $$PPAAGGEERR, and then the default chosen at compile time (usually
           _l_e_s_s).

           When the LLEESSSS environment variable is unset, Git sets it to FFRRXX (if
           LLEESSSS environment variable is set, Git does not change it at all).
           If you want to selectively override Git’s default setting for LLEESSSS,
           you can set ccoorree..ppaaggeerr to e.g.  lleessss --SS. This will be passed to the
           shell by Git, which will translate the final command to LLEESSSS==FFRRXX
           lleessss --SS. The environment does not set the SS option but the command
           line does, instructing less to truncate long lines. Similarly,
           setting ccoorree..ppaaggeerr to lleessss --++FF will deactivate the FF option
           specified by the environment from the command-line, deactivating
           the "quit if one screen" behavior of lleessss. One can specifically
           activate some flags for particular commands: for example, setting
           ppaaggeerr..bbllaammee to lleessss --SS enables line truncation only for ggiitt bbllaammee.

           Likewise, when the LLVV environment variable is unset, Git sets it to
           --cc. You can override this setting by exporting LLVV with another
           value or setting ccoorree..ppaaggeerr to llvv ++cc.

       core.whitespace
           A comma separated list of common whitespace problems to notice.
           _g_i_t _d_i_f_f will use ccoolloorr..ddiiffff..wwhhiitteessppaaccee to highlight them, and _g_i_t
           _a_p_p_l_y _-_-_w_h_i_t_e_s_p_a_c_e_=_e_r_r_o_r will consider them as errors. You can
           prefix -- to disable any of them (e.g.  --ttrraaiilliinngg--ssppaaccee):

           ·   bbllaannkk--aatt--eeooll treats trailing whitespaces at the end of the line
               as an error (enabled by default).

           ·   ssppaaccee--bbeeffoorree--ttaabb treats a space character that appears
               immediately before a tab character in the initial indent part
               of the line as an error (enabled by default).

           ·   iinnddeenntt--wwiitthh--nnoonn--ttaabb treats a line that is indented with space
               characters instead of the equivalent tabs as an error (not
               enabled by default).

           ·   ttaabb--iinn--iinnddeenntt treats a tab character in the initial indent part
               of the line as an error (not enabled by default).

           ·   bbllaannkk--aatt--eeooff treats blank lines added at the end of file as an
               error (enabled by default).

           ·   ttrraaiilliinngg--ssppaaccee is a short-hand to cover both bbllaannkk--aatt--eeooll and
               bbllaannkk--aatt--eeooff.

           ·   ccrr--aatt--eeooll treats a carriage-return at the end of line as part
               of the line terminator, i.e. with it, ttrraaiilliinngg--ssppaaccee does not
               trigger if the character before such a carriage-return is not a
               whitespace (not enabled by default).

           ·   ttaabbwwiiddtthh==<<nn>> tells how many character positions a tab occupies;
               this is relevant for iinnddeenntt--wwiitthh--nnoonn--ttaabb and when Git fixes
               ttaabb--iinn--iinnddeenntt errors. The default tab width is 8. Allowed
               values are 1 to 63.

       core.fsyncObjectFiles
           This boolean will enable _f_s_y_n_c_(_) when writing object files.

           This is a total waste of time and effort on a filesystem that
           orders data writes properly, but can be useful for filesystems that
           do not use journalling (traditional UNIX filesystems) or that only
           journal metadata and not file contents (OS X’s HFS+, or Linux ext3
           with "data=writeback").

       core.preloadIndex
           Enable parallel index preload for operations like _g_i_t _d_i_f_f

           This can speed up operations like _g_i_t _d_i_f_f and _g_i_t _s_t_a_t_u_s
           especially on filesystems like NFS that have weak caching semantics
           and thus relatively high IO latencies. When enabled, Git will do
           the index comparison to the filesystem data in parallel, allowing
           overlapping IO’s. Defaults to true.

       core.createObject
           You can set this to _l_i_n_k, in which case a hardlink followed by a
           delete of the source are used to make sure that object creation
           will not overwrite existing objects.

           On some file system/operating system combinations, this is
           unreliable. Set this config setting to _r_e_n_a_m_e there; However, This
           will remove the check that makes sure that existing object files
           will not get overwritten.

       core.notesRef
           When showing commit messages, also show notes which are stored in
           the given ref. The ref must be fully qualified. If the given ref
           does not exist, it is not an error but means that no notes should
           be printed.

           This setting defaults to "refs/notes/commits", and it can be
           overridden by the GGIITT__NNOOTTEESS__RREEFF environment variable. See ggiitt--
           nnootteess(1).

       core.sparseCheckout
           Enable "sparse checkout" feature. See section "Sparse checkout" in
           ggiitt--rreeaadd--ttrreeee(1) for more information.

       core.abbrev
           Set the length object names are abbreviated to. If unspecified or
           set to "auto", an appropriate value is computed based on the
           approximate number of packed objects in your repository, which
           hopefully is enough for abbreviated object names to stay unique for
           some time. The minimum length is 4.

       add.ignoreErrors, add.ignore-errors (deprecated)
           Tells _g_i_t _a_d_d to continue adding files when some files cannot be
           added due to indexing errors. Equivalent to the ----iiggnnoorree--eerrrroorrss
           option of ggiitt--aadddd(1).  aadddd..iiggnnoorree--eerrrroorrss is deprecated, as it does
           not follow the usual naming convention for configuration variables.

       alias.*
           Command aliases for the ggiitt(1) command wrapper - e.g. after
           defining "alias.last = cat-file commit HEAD", the invocation "git
           last" is equivalent to "git cat-file commit HEAD". To avoid
           confusion and troubles with script usage, aliases that hide
           existing Git commands are ignored. Arguments are split by spaces,
           the usual shell quoting and escaping is supported. A quote pair or
           a backslash can be used to quote them.

           If the alias expansion is prefixed with an exclamation point, it
           will be treated as a shell command. For example, defining
           "alias.new = !gitk --all --not ORIG_HEAD", the invocation "git new"
           is equivalent to running the shell command "gitk --all --not
           ORIG_HEAD". Note that shell commands will be executed from the
           top-level directory of a repository, which may not necessarily be
           the current directory.  GGIITT__PPRREEFFIIXX is set as returned by running
           _g_i_t _r_e_v_-_p_a_r_s_e _-_-_s_h_o_w_-_p_r_e_f_i_x from the original current directory.
           See ggiitt--rreevv--ppaarrssee(1).

       am.keepcr
           If true, git-am will call git-mailsplit for patches in mbox format
           with parameter ----kkeeeepp--ccrr. In this case git-mailsplit will not
           remove \\rr from lines ending with \\rr\\nn. Can be overridden by giving
           ----nnoo--kkeeeepp--ccrr from the command line. See ggiitt--aamm(1), ggiitt--
           mmaaiillsspplliitt(1).

       am.threeWay
           By default, ggiitt aamm will fail if the patch does not apply cleanly.
           When set to true, this setting tells ggiitt aamm to fall back on 3-way
           merge if the patch records the identity of blobs it is supposed to
           apply to and we have those blobs available locally (equivalent to
           giving the ----33wwaayy option from the command line). Defaults to ffaallssee.
           See ggiitt--aamm(1).

       apply.ignoreWhitespace
           When set to _c_h_a_n_g_e, tells _g_i_t _a_p_p_l_y to ignore changes in
           whitespace, in the same way as the ----iiggnnoorree--ssppaaccee--cchhaannggee option.
           When set to one of: no, none, never, false tells _g_i_t _a_p_p_l_y to
           respect all whitespace differences. See ggiitt--aappppllyy(1).

       apply.whitespace
           Tells _g_i_t _a_p_p_l_y how to handle whitespaces, in the same way as the
           ----wwhhiitteessppaaccee option. See ggiitt--aappppllyy(1).

       branch.autoSetupMerge
           Tells _g_i_t _b_r_a_n_c_h and _g_i_t _c_h_e_c_k_o_u_t to set up new branches so that
           ggiitt--ppuullll(1) will appropriately merge from the starting point
           branch. Note that even if this option is not set, this behavior can
           be chosen per-branch using the ----ttrraacckk and ----nnoo--ttrraacckk options. The
           valid settings are: ffaallssee — no automatic setup is done; ttrruuee —
           automatic setup is done when the starting point is a
           remote-tracking branch; aallwwaayyss —  automatic setup is done when the
           starting point is either a local branch or remote-tracking branch.
           This option defaults to true.

       branch.autoSetupRebase
           When a new branch is created with _g_i_t _b_r_a_n_c_h or _g_i_t _c_h_e_c_k_o_u_t that
           tracks another branch, this variable tells Git to set up pull to
           rebase instead of merge (see "branch.<name>.rebase"). When nneevveerr,
           rebase is never automatically set to true. When llooccaall, rebase is
           set to true for tracked branches of other local branches. When
           rreemmoottee, rebase is set to true for tracked branches of
           remote-tracking branches. When aallwwaayyss, rebase will be set to true
           for all tracking branches. See "branch.autoSetupMerge" for details
           on how to set up a branch to track another branch. This option
           defaults to never.

       branch.<name>.remote
           When on branch <name>, it tells _g_i_t _f_e_t_c_h and _g_i_t _p_u_s_h which remote
           to fetch from/push to. The remote to push to may be overridden with
           rreemmoottee..ppuusshhDDeeffaauulltt (for all branches). The remote to push to, for
           the current branch, may be further overridden by
           bbrraanncchh..<<nnaammee>>..ppuusshhRReemmoottee. If no remote is configured, or if you are
           not on any branch, it defaults to oorriiggiinn for fetching and
           rreemmoottee..ppuusshhDDeeffaauulltt for pushing. Additionally, ..  (a period) is the
           current local repository (a dot-repository), see
           bbrraanncchh..<<nnaammee>>..mmeerrggee's final note below.

       branch.<name>.pushRemote
           When on branch <name>, it overrides bbrraanncchh..<<nnaammee>>..rreemmoottee for
           pushing. It also overrides rreemmoottee..ppuusshhDDeeffaauulltt for pushing from
           branch <name>. When you pull from one place (e.g. your upstream)
           and push to another place (e.g. your own publishing repository),
           you would want to set rreemmoottee..ppuusshhDDeeffaauulltt to specify the remote to
           push to for all branches, and use this option to override it for a
           specific branch.

       branch.<name>.merge
           Defines, together with branch.<name>.remote, the upstream branch
           for the given branch. It tells _g_i_t _f_e_t_c_h/_g_i_t _p_u_l_l/_g_i_t _r_e_b_a_s_e which
           branch to merge and can also affect _g_i_t _p_u_s_h (see push.default).
           When in branch <name>, it tells _g_i_t _f_e_t_c_h the default refspec to be
           marked for merging in FETCH_HEAD. The value is handled like the
           remote part of a refspec, and must match a ref which is fetched
           from the remote given by "branch.<name>.remote". The merge
           information is used by _g_i_t _p_u_l_l (which at first calls _g_i_t _f_e_t_c_h) to
           lookup the default branch for merging. Without this option, _g_i_t
           _p_u_l_l defaults to merge the first refspec fetched. Specify multiple
           values to get an octopus merge. If you wish to setup _g_i_t _p_u_l_l so
           that it merges into <name> from another branch in the local
           repository, you can point branch.<name>.merge to the desired
           branch, and use the relative path setting ..  (a period) for
           branch.<name>.remote.

       branch.<name>.mergeOptions
           Sets default options for merging into branch <name>. The syntax and
           supported options are the same as those of ggiitt--mmeerrggee(1), but option
           values containing whitespace characters are currently not
           supported.

       branch.<name>.rebase
           When true, rebase the branch <name> on top of the fetched branch,
           instead of merging the default branch from the default remote when
           "git pull" is run. See "pull.rebase" for doing this in a non
           branch-specific manner.

           When preserve, also pass ----pprreesseerrvvee--mmeerrggeess along to _g_i_t _r_e_b_a_s_e so
           that locally committed merge commits will not be flattened by
           running _g_i_t _p_u_l_l.

           When the value is iinntteerraaccttiivvee, the rebase is run in interactive
           mode.

           NNOOTTEE: this is a possibly dangerous operation; do nnoott use it unless
           you understand the implications (see ggiitt--rreebbaassee(1) for details).

       branch.<name>.description
           Branch description, can be edited with ggiitt bbrraanncchh
           ----eeddiitt--ddeessccrriippttiioonn. Branch description is automatically added in
           the format-patch cover letter or request-pull summary.

       browser.<tool>.cmd
           Specify the command to invoke the specified browser. The specified
           command is evaluated in shell with the URLs passed as arguments.
           (See ggiitt--wweebb----bbrroowwssee(1).)

       browser.<tool>.path
           Override the path for the given tool that may be used to browse
           HTML help (see --ww option in ggiitt--hheellpp(1)) or a working repository in
           gitweb (see ggiitt--iinnssttaawweebb(1)).

       clean.requireForce
           A boolean to make git-clean do nothing unless given -f, -i or -n.
           Defaults to true.

       color.branch
           A boolean to enable/disable color in the output of ggiitt--bbrraanncchh(1).
           May be set to aallwwaayyss, ffaallssee (or nneevveerr) or aauuttoo (or ttrruuee), in which
           case colors are used only when the output is to a terminal. If
           unset, then the value of ccoolloorr..uuii is used (aauuttoo by default).

       color.branch.<slot>
           Use customized color for branch coloration.  <<sslloott>> is one of
           ccuurrrreenntt (the current branch), llooccaall (a local branch), rreemmoottee (a
           remote-tracking branch in refs/remotes/), uuppssttrreeaamm (upstream
           tracking branch), ppllaaiinn (other refs).

       color.diff
           Whether to use ANSI escape sequences to add color to patches. If
           this is set to aallwwaayyss, ggiitt--ddiiffff(1), ggiitt--lloogg(1), and ggiitt--sshhooww(1)
           will use color for all patches. If it is set to ttrruuee or aauuttoo, those
           commands will only use color when output is to the terminal. If
           unset, then the value of ccoolloorr..uuii is used (aauuttoo by default).

           This does not affect ggiitt--ffoorrmmaatt--ppaattcchh(1) or the _g_i_t_-_d_i_f_f_-_* plumbing
           commands. Can be overridden on the command line with the
           ----ccoolloorr[[==<<wwhheenn>>]] option.

       color.diff.<slot>
           Use customized color for diff colorization.  <<sslloott>> specifies which
           part of the patch to use the specified color, and is one of ccoonntteexxtt
           (context text - ppllaaiinn is a historical synonym), mmeettaa
           (metainformation), ffrraagg (hunk header), _f_u_n_c (function in hunk
           header), oolldd (removed lines), nneeww (added lines), ccoommmmiitt (commit
           headers), or wwhhiitteessppaaccee (highlighting whitespace errors).

       color.decorate.<slot>
           Use customized color for _g_i_t _l_o_g _-_-_d_e_c_o_r_a_t_e output.  <<sslloott>> is one
           of bbrraanncchh, rreemmootteeBBrraanncchh, ttaagg, ssttaasshh or HHEEAADD for local branches,
           remote-tracking branches, tags, stash and HEAD, respectively.

       color.grep
           When set to aallwwaayyss, always highlight matches. When ffaallssee (or
           nneevveerr), never. When set to ttrruuee or aauuttoo, use color only when the
           output is written to the terminal. If unset, then the value of
           ccoolloorr..uuii is used (aauuttoo by default).

       color.grep.<slot>
           Use customized color for grep colorization.  <<sslloott>> specifies which
           part of the line to use the specified color, and is one of

           ccoonntteexxtt
               non-matching text in context lines (when using --AA, --BB, or --CC)

           ffiilleennaammee
               filename prefix (when not using --hh)

           ffuunnccttiioonn
               function name lines (when using --pp)

           lliinneennuummbbeerr
               line number prefix (when using --nn)

           mmaattcchh
               matching text (same as setting mmaattcchhCCoonntteexxtt and mmaattcchhSSeelleecctteedd)

           mmaattcchhCCoonntteexxtt
               matching text in context lines

           mmaattcchhSSeelleecctteedd
               matching text in selected lines

           sseelleecctteedd
               non-matching text in selected lines

           sseeppaarraattoorr
               separators between fields on a line (::, --, and ==) and between
               hunks (----)

       color.interactive
           When set to aallwwaayyss, always use colors for interactive prompts and
           displays (such as those used by "git-add --interactive" and
           "git-clean --interactive"). When false (or nneevveerr), never. When set
           to ttrruuee or aauuttoo, use colors only when the output is to the
           terminal. If unset, then the value of ccoolloorr..uuii is used (aauuttoo by
           default).

       color.interactive.<slot>
           Use customized color for _g_i_t _a_d_d _-_-_i_n_t_e_r_a_c_t_i_v_e and _g_i_t _c_l_e_a_n
           _-_-_i_n_t_e_r_a_c_t_i_v_e output.  <<sslloott>> may be pprroommpptt, hheeaaddeerr, hheellpp or eerrrroorr,
           for four distinct types of normal output from interactive commands.

       color.pager
           A boolean to enable/disable colored output when the pager is in use
           (default is true).

       color.showBranch
           A boolean to enable/disable color in the output of ggiitt--sshhooww--
           bbrraanncchh(1). May be set to aallwwaayyss, ffaallssee (or nneevveerr) or aauuttoo (or
           ttrruuee), in which case colors are used only when the output is to a
           terminal. If unset, then the value of ccoolloorr..uuii is used (aauuttoo by
           default).

       color.status
           A boolean to enable/disable color in the output of ggiitt--ssttaattuuss(1).
           May be set to aallwwaayyss, ffaallssee (or nneevveerr) or aauuttoo (or ttrruuee), in which
           case colors are used only when the output is to a terminal. If
           unset, then the value of ccoolloorr..uuii is used (aauuttoo by default).

       color.status.<slot>
           Use customized color for status colorization.  <<sslloott>> is one of
           hheeaaddeerr (the header text of the status message), aaddddeedd or uuppddaatteedd
           (files which are added but not committed), cchhaannggeedd (files which are
           changed but not added in the index), uunnttrraacckkeedd (files which are not
           tracked by Git), bbrraanncchh (the current branch), nnoobbrraanncchh (the color
           the _n_o _b_r_a_n_c_h warning is shown in, defaulting to red), or uunnmmeerrggeedd
           (files which have unmerged changes).

       color.ui
           This variable determines the default value for variables such as
           ccoolloorr..ddiiffff and ccoolloorr..ggrreepp that control the use of color per command
           family. Its scope will expand as more commands learn configuration
           to set a default for the ----ccoolloorr option. Set it to ffaallssee or nneevveerr
           if you prefer Git commands not to use color unless enabled
           explicitly with some other configuration or the ----ccoolloorr option. Set
           it to aallwwaayyss if you want all output not intended for machine
           consumption to use color, to ttrruuee or aauuttoo (this is the default
           since Git 1.8.4) if you want such output to use color when written
           to the terminal.

       column.ui
           Specify whether supported commands should output in columns. This
           variable consists of a list of tokens separated by spaces or
           commas:

           These options control when the feature should be enabled (defaults
           to _n_e_v_e_r):

           aallwwaayyss
               always show in columns

           nneevveerr
               never show in columns

           aauuttoo
               show in columns if the output is to the terminal

           These options control layout (defaults to _c_o_l_u_m_n). Setting any of
           these implies _a_l_w_a_y_s if none of _a_l_w_a_y_s, _n_e_v_e_r, or _a_u_t_o are
           specified.

           ccoolluummnn
               fill columns before rows

           rrooww
               fill rows before columns

           ppllaaiinn
               show in one column

           Finally, these options can be combined with a layout option
           (defaults to _n_o_d_e_n_s_e):

           ddeennssee
               make unequal size columns to utilize more space

           nnooddeennssee
               make equal size columns

       column.branch
           Specify whether to output branch listing in ggiitt bbrraanncchh in columns.
           See ccoolluummnn..uuii for details.

       column.clean
           Specify the layout when list items in ggiitt cclleeaann --ii, which always
           shows files and directories in columns. See ccoolluummnn..uuii for details.

       column.status
           Specify whether to output untracked files in ggiitt ssttaattuuss in columns.
           See ccoolluummnn..uuii for details.

       column.tag
           Specify whether to output tag listing in ggiitt ttaagg in columns. See
           ccoolluummnn..uuii for details.

       commit.cleanup
           This setting overrides the default of the ----cclleeaannuupp option in ggiitt
           ccoommmmiitt. See ggiitt--ccoommmmiitt(1) for details. Changing the default can be
           useful when you always want to keep lines that begin with comment
           character ## in your log message, in which case you would do ggiitt
           ccoonnffiigg ccoommmmiitt..cclleeaannuupp wwhhiitteessppaaccee (note that you will have to remove
           the help lines that begin with ## in the commit log template
           yourself, if you do this).

       commit.gpgSign
           A boolean to specify whether all commits should be GPG signed. Use
           of this option when doing operations such as rebase can result in a
           large number of commits being signed. It may be convenient to use
           an agent to avoid typing your GPG passphrase several times.

       commit.status
           A boolean to enable/disable inclusion of status information in the
           commit message template when using an editor to prepare the commit
           message. Defaults to true.

       commit.template
           Specify the pathname of a file to use as the template for new
           commit messages.

       commit.verbose
           A boolean or int to specify the level of verbose with ggiitt ccoommmmiitt.
           See ggiitt--ccoommmmiitt(1).

       credential.helper
           Specify an external helper to be called when a username or password
           credential is needed; the helper may consult external storage to
           avoid prompting the user for the credentials. Note that multiple
           helpers may be defined. See ggiittccrreeddeennttiiaallss(7) for details.

       credential.useHttpPath
           When acquiring credentials, consider the "path" component of an
           http or https URL to be important. Defaults to false. See
           ggiittccrreeddeennttiiaallss(7) for more information.

       credential.username
           If no username is set for a network authentication, use this
           username by default. See credential.<context>.* below, and
           ggiittccrreeddeennttiiaallss(7).

       credential.<url>.*
           Any of the credential.* options above can be applied selectively to
           some credentials. For example
           "credential.https://example.com.username" would set the default
           username only for https connections to example.com. See
           ggiittccrreeddeennttiiaallss(7) for details on how URLs are matched.

       credentialCache.ignoreSIGHUP
           Tell git-credential-cache—daemon to ignore SIGHUP, instead of
           quitting.

       diff.autoRefreshIndex
           When using _g_i_t _d_i_f_f to compare with work tree files, do not
           consider stat-only change as changed. Instead, silently run ggiitt
           uuppddaattee--iinnddeexx ----rreeffrreesshh to update the cached stat information for
           paths whose contents in the work tree match the contents in the
           index. This option defaults to true. Note that this affects only
           _g_i_t _d_i_f_f Porcelain, and not lower level _d_i_f_f commands such as _g_i_t
           _d_i_f_f_-_f_i_l_e_s.

       diff.dirstat
           A comma separated list of ----ddiirrssttaatt parameters specifying the
           default behavior of the ----ddiirrssttaatt option to ggiitt--ddiiffff(1)` and
           friends. The defaults can be overridden on the command line (using
           ----ddiirrssttaatt==<<ppaarraamm11,,ppaarraamm22,,......>>). The fallback defaults (when not
           changed by ddiiffff..ddiirrssttaatt) are cchhaannggeess,,nnoonnccuummuullaattiivvee,,33. The following
           parameters are available:

           cchhaannggeess
               Compute the dirstat numbers by counting the lines that have
               been removed from the source, or added to the destination. This
               ignores the amount of pure code movements within a file. In
               other words, rearranging lines in a file is not counted as much
               as other changes. This is the default behavior when no
               parameter is given.

           lliinneess
               Compute the dirstat numbers by doing the regular line-based
               diff analysis, and summing the removed/added line counts. (For
               binary files, count 64-byte chunks instead, since binary files
               have no natural concept of lines). This is a more expensive
               ----ddiirrssttaatt behavior than the cchhaannggeess behavior, but it does count
               rearranged lines within a file as much as other changes. The
               resulting output is consistent with what you get from the other
               ----**ssttaatt options.

           ffiilleess
               Compute the dirstat numbers by counting the number of files
               changed. Each changed file counts equally in the dirstat
               analysis. This is the computationally cheapest ----ddiirrssttaatt
               behavior, since it does not have to look at the file contents
               at all.

           ccuummuullaattiivvee
               Count changes in a child directory for the parent directory as
               well. Note that when using ccuummuullaattiivvee, the sum of the
               percentages reported may exceed 100%. The default
               (non-cumulative) behavior can be specified with the
               nnoonnccuummuullaattiivvee parameter.

           <limit>
               An integer parameter specifies a cut-off percent (3% by
               default). Directories contributing less than this percentage of
               the changes are not shown in the output.

           Example: The following will count changed files, while ignoring
           directories with less than 10% of the total amount of changed
           files, and accumulating child directory counts in the parent
           directories: ffiilleess,,1100,,ccuummuullaattiivvee.

       diff.statGraphWidth
           Limit the width of the graph part in --stat output. If set, applies
           to all commands generating --stat output except format-patch.

       diff.context
           Generate diffs with <n> lines of context instead of the default of
           3. This value is overridden by the -U option.

       diff.interHunkContext
           Show the context between diff hunks, up to the specified number of
           lines, thereby fusing the hunks that are close to each other. This
           value serves as the default for the ----iinntteerr--hhuunnkk--ccoonntteexxtt command
           line option.

       diff.external
           If this config variable is set, diff generation is not performed
           using the internal diff machinery, but using the given command. Can
           be overridden with the ‘GIT_EXTERNAL_DIFF’ environment variable.
           The command is called with parameters as described under "git
           Diffs" in ggiitt(1). Note: if you want to use an external diff program
           only on a subset of your files, you might want to use
           ggiittaattttrriibbuutteess(5) instead.

       diff.ignoreSubmodules
           Sets the default value of --ignore-submodules. Note that this
           affects only _g_i_t _d_i_f_f Porcelain, and not lower level _d_i_f_f commands
           such as _g_i_t _d_i_f_f_-_f_i_l_e_s.  _g_i_t _c_h_e_c_k_o_u_t also honors this setting when
           reporting uncommitted changes. Setting it to _a_l_l disables the
           submodule summary normally shown by _g_i_t _c_o_m_m_i_t and _g_i_t _s_t_a_t_u_s when
           ssttaattuuss..ssuubbmmoodduulleeSSuummmmaarryy is set unless it is overridden by using the
           --ignore-submodules command-line option. The _g_i_t _s_u_b_m_o_d_u_l_e commands
           are not affected by this setting.

       diff.mnemonicPrefix
           If set, _g_i_t _d_i_f_f uses a prefix pair that is different from the
           standard "a/" and "b/" depending on what is being compared. When
           this configuration is in effect, reverse diff output also swaps the
           order of the prefixes:

           ggiitt ddiiffff
               compares the (i)ndex and the (w)ork tree;

           ggiitt ddiiffff HHEEAADD
               compares a (c)ommit and the (w)ork tree;

           ggiitt ddiiffff ----ccaacchheedd
               compares a (c)ommit and the (i)ndex;

           ggiitt ddiiffff HHEEAADD::ffiillee11 ffiillee22
               compares an (o)bject and a (w)ork tree entity;

           ggiitt ddiiffff ----nnoo--iinnddeexx aa bb
               compares two non-git things (1) and (2).

       diff.noprefix
           If set, _g_i_t _d_i_f_f does not show any source or destination prefix.

       diff.orderFile
           File indicating how to order files within a diff. See the _-_O option
           to ggiitt--ddiiffff(1) for details. If ddiiffff..oorrddeerrFFiillee is a relative
           pathname, it is treated as relative to the top of the working tree.

       diff.renameLimit
           The number of files to consider when performing the copy/rename
           detection; equivalent to the _g_i_t _d_i_f_f option --ll.

       diff.renames
           Whether and how Git detects renames. If set to "false", rename
           detection is disabled. If set to "true", basic rename detection is
           enabled. If set to "copies" or "copy", Git will detect copies, as
           well. Defaults to true. Note that this affects only _g_i_t _d_i_f_f
           Porcelain like ggiitt--ddiiffff(1) and ggiitt--lloogg(1), and not lower level
           commands such as ggiitt--ddiiffff--ffiilleess(1).

       diff.suppressBlankEmpty
           A boolean to inhibit the standard behavior of printing a space
           before each empty output line. Defaults to false.

       diff.submodule
           Specify the format in which differences in submodules are shown.
           The "short" format just shows the names of the commits at the
           beginning and end of the range. The "log" format lists the commits
           in the range like ggiitt--ssuubbmmoodduullee(1)ssuummmmaarryy does. The "diff" format
           shows an inline diff of the changed contents of the submodule.
           Defaults to "short".

       diff.wordRegex
           A POSIX Extended Regular Expression used to determine what is a
           "word" when performing word-by-word difference calculations.
           Character sequences that match the regular expression are "words",
           all other characters are iiggnnoorraabbllee whitespace.

       diff.<driver>.command
           The custom diff driver command. See ggiittaattttrriibbuutteess(5) for details.

       diff.<driver>.xfuncname
           The regular expression that the diff driver should use to recognize
           the hunk header. A built-in pattern may also be used. See
           ggiittaattttrriibbuutteess(5) for details.

       diff.<driver>.binary
           Set this option to true to make the diff driver treat files as
           binary. See ggiittaattttrriibbuutteess(5) for details.

       diff.<driver>.textconv
           The command that the diff driver should call to generate the
           text-converted version of a file. The result of the conversion is
           used to generate a human-readable diff. See ggiittaattttrriibbuutteess(5) for
           details.

       diff.<driver>.wordRegex
           The regular expression that the diff driver should use to split
           words in a line. See ggiittaattttrriibbuutteess(5) for details.

       diff.<driver>.cachetextconv
           Set this option to true to make the diff driver cache the text
           conversion outputs. See ggiittaattttrriibbuutteess(5) for details.

       diff.tool
           Controls which diff tool is used by ggiitt--ddiiffffttooooll(1). This variable
           overrides the value configured in mmeerrggee..ttooooll. The list below shows
           the valid built-in values. Any other value is treated as a custom
           diff tool and requires that a corresponding difftool.<tool>.cmd
           variable is defined.

           ·   araxis

           ·   bc

           ·   bc3

           ·   codecompare

           ·   deltawalker

           ·   diffmerge

           ·   diffuse

           ·   ecmerge

           ·   emerge

           ·   examdiff

           ·   gvimdiff

           ·   gvimdiff2

           ·   gvimdiff3

           ·   kdiff3

           ·   kompare

           ·   meld

           ·   opendiff

           ·   p4merge

           ·   tkdiff

           ·   vimdiff

           ·   vimdiff2

           ·   vimdiff3

           ·   winmerge

           ·   xxdiff

       diff.indentHeuristic
           Set this option to ttrruuee to enable experimental heuristics that
           shift diff hunk boundaries to make patches easier to read.

       diff.algorithm
           Choose a diff algorithm. The variants are as follows:

           ddeeffaauulltt, mmyyeerrss
               The basic greedy diff algorithm. Currently, this is the
               default.

           mmiinniimmaall
               Spend extra time to make sure the smallest possible diff is
               produced.

           ppaattiieennccee
               Use "patience diff" algorithm when generating patches.

           hhiissttooggrraamm
               This algorithm extends the patience algorithm to "support
               low-occurrence common elements".

       diff.wsErrorHighlight
           A comma separated list of oolldd, nneeww, ccoonntteexxtt, that specifies how
           whitespace errors on lines are highlighted with
           ccoolloorr..ddiiffff..wwhhiitteessppaaccee. Can be overridden by the command line option
           ----wwss--eerrrroorr--hhiigghhlliigghhtt==<<kkiinndd>>

       difftool.<tool>.path
           Override the path for the given tool. This is useful in case your
           tool is not in the PATH.

       difftool.<tool>.cmd
           Specify the command to invoke the specified diff tool. The
           specified command is evaluated in shell with the following
           variables available: _L_O_C_A_L is set to the name of the temporary file
           containing the contents of the diff pre-image and _R_E_M_O_T_E is set to
           the name of the temporary file containing the contents of the diff
           post-image.

       difftool.prompt
           Prompt before each invocation of the diff tool.

       fastimport.unpackLimit
           If the number of objects imported by ggiitt--ffaasstt--iimmppoorrtt(1) is below
           this limit, then the objects will be unpacked into loose object
           files. However if the number of imported objects equals or exceeds
           this limit then the pack will be stored as a pack. Storing the pack
           from a fast-import can make the import operation complete faster,
           especially on slow filesystems. If not set, the value of
           ttrraannssffeerr..uunnppaacckkLLiimmiitt is used instead.

       fetch.recurseSubmodules
           This option can be either set to a boolean value or to _o_n_-_d_e_m_a_n_d.
           Setting it to a boolean changes the behavior of fetch and pull to
           unconditionally recurse into submodules when set to true or to not
           recurse at all when set to false. When set to _o_n_-_d_e_m_a_n_d (the
           default value), fetch and pull will only recurse into a populated
           submodule when its superproject retrieves a commit that updates the
           submodule’s reference.

       fetch.fsckObjects
           If it is set to true, git-fetch-pack will check all fetched
           objects. It will abort in the case of a malformed object or a
           broken link. The result of an abort are only dangling objects.
           Defaults to false. If not set, the value of ttrraannssffeerr..ffsscckkOObbjjeeccttss is
           used instead.

       fetch.unpackLimit
           If the number of objects fetched over the Git native transfer is
           below this limit, then the objects will be unpacked into loose
           object files. However if the number of received objects equals or
           exceeds this limit then the received pack will be stored as a pack,
           after adding any missing delta bases. Storing the pack from a push
           can make the push operation complete faster, especially on slow
           filesystems. If not set, the value of ttrraannssffeerr..uunnppaacckkLLiimmiitt is used
           instead.

       fetch.prune
           If true, fetch will automatically behave as if the ----pprruunnee option
           was given on the command line. See also rreemmoottee..<<nnaammee>>..pprruunnee.

       fetch.output
           Control how ref update status is printed. Valid values are ffuullll and
           ccoommppaacctt. Default value is ffuullll. See section OUTPUT in ggiitt--ffeettcchh(1)
           for detail.

       format.attach
           Enable multipart/mixed attachments as the default for _f_o_r_m_a_t_-_p_a_t_c_h.
           The value can also be a double quoted string which will enable
           attachments as the default and set the value as the boundary. See
           the --attach option in ggiitt--ffoorrmmaatt--ppaattcchh(1).

       format.from
           Provides the default value for the ----ffrroomm option to format-patch.
           Accepts a boolean value, or a name and email address. If false,
           format-patch defaults to ----nnoo--ffrroomm, using commit authors directly
           in the "From:" field of patch mails. If true, format-patch defaults
           to ----ffrroomm, using your committer identity in the "From:" field of
           patch mails and including a "From:" field in the body of the patch
           mail if different. If set to a non-boolean value, format-patch uses
           that value instead of your committer identity. Defaults to false.

       format.numbered
           A boolean which can enable or disable sequence numbers in patch
           subjects. It defaults to "auto" which enables it only if there is
           more than one patch. It can be enabled or disabled for all messages
           by setting it to "true" or "false". See --numbered option in ggiitt--
           ffoorrmmaatt--ppaattcchh(1).

       format.headers
           Additional email headers to include in a patch to be submitted by
           mail. See ggiitt--ffoorrmmaatt--ppaattcchh(1).

       format.to, format.cc
           Additional recipients to include in a patch to be submitted by
           mail. See the --to and --cc options in ggiitt--ffoorrmmaatt--ppaattcchh(1).

       format.subjectPrefix
           The default for format-patch is to output files with the _[_P_A_T_C_H_]
           subject prefix. Use this variable to change that prefix.

       format.signature
           The default for format-patch is to output a signature containing
           the Git version number. Use this variable to change that default.
           Set this variable to the empty string ("") to suppress signature
           generation.

       format.signatureFile
           Works just like format.signature except the contents of the file
           specified by this variable will be used as the signature.

       format.suffix
           The default for format-patch is to output files with the suffix
           ..ppaattcchh. Use this variable to change that suffix (make sure to
           include the dot if you want it).

       format.pretty
           The default pretty format for log/show/whatchanged command, See
           ggiitt--lloogg(1), ggiitt--sshhooww(1), ggiitt--wwhhaattcchhaannggeedd(1).

       format.thread
           The default threading style for _g_i_t _f_o_r_m_a_t_-_p_a_t_c_h. Can be a boolean
           value, or sshhaallllooww or ddeeeepp.  sshhaallllooww threading makes every mail a
           reply to the head of the series, where the head is chosen from the
           cover letter, the ----iinn--rreeppllyy--ttoo, and the first patch mail, in this
           order.  ddeeeepp threading makes every mail a reply to the previous
           one. A true boolean value is the same as sshhaallllooww, and a false value
           disables threading.

       format.signOff
           A boolean value which lets you enable the --ss//----ssiiggnnooffff option of
           format-patch by default.  NNoottee:: Adding the Signed-off-by: line to a
           patch should be a conscious act and means that you certify you have
           the rights to submit this work under the same open source license.
           Please see the _S_u_b_m_i_t_t_i_n_g_P_a_t_c_h_e_s document for further discussion.

       format.coverLetter
           A boolean that controls whether to generate a cover-letter when
           format-patch is invoked, but in addition can be set to "auto", to
           generate a cover-letter only when there’s more than one patch.

       format.outputDirectory
           Set a custom directory to store the resulting files instead of the
           current working directory.

       format.useAutoBase
           A boolean value which lets you enable the ----bbaassee==aauuttoo option of
           format-patch by default.

       filter.<driver>.clean
           The command which is used to convert the content of a worktree file
           to a blob upon checkin. See ggiittaattttrriibbuutteess(5) for details.

       filter.<driver>.smudge
           The command which is used to convert the content of a blob object
           to a worktree file upon checkout. See ggiittaattttrriibbuutteess(5) for details.

       fsck.<msg-id>
           Allows overriding the message type (error, warn or ignore) of a
           specific message ID such as mmiissssiinnggEEmmaaiill.

           For convenience, fsck prefixes the error/warning with the message
           ID, e.g. "missingEmail: invalid author/committer line - missing
           email" means that setting ffsscckk..mmiissssiinnggEEmmaaiill == iiggnnoorree will hide that
           issue.

           This feature is intended to support working with legacy
           repositories which cannot be repaired without disruptive changes.

       fsck.skipList
           The path to a sorted list of object names (i.e. one SHA-1 per line)
           that are known to be broken in a non-fatal way and should be
           ignored. This feature is useful when an established project should
           be accepted despite early commits containing errors that can be
           safely ignored such as invalid committer email addresses. Note:
           corrupt objects cannot be skipped with this setting.

       gc.aggressiveDepth
           The depth parameter used in the delta compression algorithm used by
           _g_i_t _g_c _-_-_a_g_g_r_e_s_s_i_v_e. This defaults to 50.

       gc.aggressiveWindow
           The window size parameter used in the delta compression algorithm
           used by _g_i_t _g_c _-_-_a_g_g_r_e_s_s_i_v_e. This defaults to 250.

       gc.auto
           When there are approximately more than this many loose objects in
           the repository, ggiitt ggcc ----aauuttoo will pack them. Some Porcelain
           commands use this command to perform a light-weight garbage
           collection from time to time. The default value is 6700. Setting
           this to 0 disables it.

       gc.autoPackLimit
           When there are more than this many packs that are not marked with
           **..kkeeeepp file in the repository, ggiitt ggcc ----aauuttoo consolidates them into
           one larger pack. The default value is 50. Setting this to 0
           disables it.

       gc.autoDetach
           Make ggiitt ggcc ----aauuttoo return immediately and run in background if the
           system supports it. Default is true.

       gc.logExpiry
           If the file gc.log exists, then ggiitt ggcc ----aauuttoo won’t run unless that
           file is more than _g_c_._l_o_g_E_x_p_i_r_y old. Default is "1.day". See
           ggcc..pprruunneeEExxppiirree for more ways to specify its value.

       gc.packRefs
           Running ggiitt ppaacckk--rreeffss in a repository renders it unclonable by Git
           versions prior to 1.5.1.2 over dumb transports such as HTTP. This
           variable determines whether _g_i_t _g_c runs ggiitt ppaacckk--rreeffss. This can be
           set to nnoottbbaarree to enable it within all non-bare repos or it can be
           set to a boolean value. The default is ttrruuee.

       gc.pruneExpire
           When _g_i_t _g_c is run, it will call _p_r_u_n_e _-_-_e_x_p_i_r_e _2_._w_e_e_k_s_._a_g_o.
           Override the grace period with this config variable. The value
           "now" may be used to disable this grace period and always prune
           unreachable objects immediately, or "never" may be used to suppress
           pruning. This feature helps prevent corruption when _g_i_t _g_c runs
           concurrently with another process writing to the repository; see
           the "NOTES" section of ggiitt--ggcc(1).

       gc.worktreePruneExpire
           When _g_i_t _g_c is run, it calls _g_i_t _w_o_r_k_t_r_e_e _p_r_u_n_e _-_-_e_x_p_i_r_e
           _3_._m_o_n_t_h_s_._a_g_o. This config variable can be used to set a different
           grace period. The value "now" may be used to disable the grace
           period and prune $$GGIITT__DDIIRR//wwoorrkkttrreeeess immediately, or "never" may be
           used to suppress pruning.

       gc.reflogExpire, gc.<pattern>.reflogExpire
           _g_i_t _r_e_f_l_o_g _e_x_p_i_r_e removes reflog entries older than this time;
           defaults to 90 days. The value "now" expires all entries
           immediately, and "never" suppresses expiration altogether. With
           "<pattern>" (e.g. "refs/stash") in the middle the setting applies
           only to the refs that match the <pattern>.

       gc.reflogExpireUnreachable, gc.<pattern>.reflogExpireUnreachable
           _g_i_t _r_e_f_l_o_g _e_x_p_i_r_e removes reflog entries older than this time and
           are not reachable from the current tip; defaults to 30 days. The
           value "now" expires all entries immediately, and "never" suppresses
           expiration altogether. With "<pattern>" (e.g. "refs/stash") in the
           middle, the setting applies only to the refs that match the
           <pattern>.

       gc.rerereResolved
           Records of conflicted merge you resolved earlier are kept for this
           many days when _g_i_t _r_e_r_e_r_e _g_c is run. The default is 60 days. See
           ggiitt--rreerreerree(1).

       gc.rerereUnresolved
           Records of conflicted merge you have not resolved are kept for this
           many days when _g_i_t _r_e_r_e_r_e _g_c is run. The default is 15 days. See
           ggiitt--rreerreerree(1).

       gitcvs.commitMsgAnnotation
           Append this string to each commit message. Set to empty string to
           disable this feature. Defaults to "via git-CVS emulator".

       gitcvs.enabled
           Whether the CVS server interface is enabled for this repository.
           See ggiitt--ccvvsssseerrvveerr(1).

       gitcvs.logFile
           Path to a log file where the CVS server interface well... logs
           various stuff. See ggiitt--ccvvsssseerrvveerr(1).

       gitcvs.usecrlfattr
           If true, the server will look up the end-of-line conversion
           attributes for files to determine the --kk modes to use. If the
           attributes force Git to treat a file as text, the --kk mode will be
           left blank so CVS clients will treat it as text. If they suppress
           text conversion, the file will be set with _-_k_b mode, which
           suppresses any newline munging the client might otherwise do. If
           the attributes do not allow the file type to be determined, then
           ggiittccvvss..aallllBBiinnaarryy is used. See ggiittaattttrriibbuutteess(5).

       gitcvs.allBinary
           This is used if ggiittccvvss..uusseeccrrllffaattttrr does not resolve the correct _-_k_b
           mode to use. If true, all unresolved files are sent to the client
           in mode _-_k_b. This causes the client to treat them as binary files,
           which suppresses any newline munging it otherwise might do.
           Alternatively, if it is set to "guess", then the contents of the
           file are examined to decide if it is binary, similar to
           ccoorree..aauuttooccrrllff.

       gitcvs.dbName
           Database used by git-cvsserver to cache revision information
           derived from the Git repository. The exact meaning depends on the
           used database driver, for SQLite (which is the default driver) this
           is a filename. Supports variable substitution (see ggiitt--ccvvsssseerrvveerr(1)
           for details). May not contain semicolons (;;). Default:
           _%_G_g_i_t_c_v_s_._%_m_._s_q_l_i_t_e

       gitcvs.dbDriver
           Used Perl DBI driver. You can specify any available driver for this
           here, but it might not work. git-cvsserver is tested with
           _D_B_D_:_:_S_Q_L_i_t_e, reported to work with _D_B_D_:_:_P_g, and reported nnoott to
           work with _D_B_D_:_:_m_y_s_q_l. Experimental feature. May not contain double
           colons (::). Default: _S_Q_L_i_t_e. See ggiitt--ccvvsssseerrvveerr(1).

       gitcvs.dbUser, gitcvs.dbPass
           Database user and password. Only useful if setting ggiittccvvss..ddbbDDrriivveerr,
           since SQLite has no concept of database users and/or passwords.
           _g_i_t_c_v_s_._d_b_U_s_e_r supports variable substitution (see ggiitt--ccvvsssseerrvveerr(1)
           for details).

       gitcvs.dbTableNamePrefix
           Database table name prefix. Prepended to the names of any database
           tables used, allowing a single database to be used for several
           repositories. Supports variable substitution (see ggiitt--ccvvsssseerrvveerr(1)
           for details). Any non-alphabetic characters will be replaced with
           underscores.

       All gitcvs variables except for ggiittccvvss..uusseeccrrllffaattttrr and ggiittccvvss..aallllBBiinnaarryy
       can also be specified as _g_i_t_c_v_s_._<_a_c_c_e_s_s___m_e_t_h_o_d_>_._<_v_a_r_n_a_m_e_> (where
       _a_c_c_e_s_s___m_e_t_h_o_d is one of "ext" and "pserver") to make them apply only
       for the given access method.

       gitweb.category, gitweb.description, gitweb.owner, gitweb.url
           See ggiittwweebb(1) for description.

       gitweb.avatar, gitweb.blame, gitweb.grep, gitweb.highlight,
       gitweb.patches, gitweb.pickaxe, gitweb.remote_heads, gitweb.showSizes,
       gitweb.snapshot
           See ggiittwweebb..ccoonnff(5) for description.

       grep.lineNumber
           If set to true, enable --nn option by default.

       grep.patternType
           Set the default matching behavior. Using a value of _b_a_s_i_c,
           _e_x_t_e_n_d_e_d, _f_i_x_e_d, or _p_e_r_l will enable the ----bbaassiicc--rreeggeexxpp,
           ----eexxtteennddeedd--rreeggeexxpp, ----ffiixxeedd--ssttrriinnggss, or ----ppeerrll--rreeggeexxpp option
           accordingly, while the value _d_e_f_a_u_l_t will return to the default
           matching behavior.

       grep.extendedRegexp
           If set to true, enable ----eexxtteennddeedd--rreeggeexxpp option by default. This
           option is ignored when the ggrreepp..ppaatttteerrnnTTyyppee option is set to a
           value other than _d_e_f_a_u_l_t.

       grep.threads
           Number of grep worker threads to use. See ggrreepp..tthhrreeaaddss in ggiitt--
           ggrreepp(1) for more information.

       grep.fallbackToNoIndex
           If set to true, fall back to git grep --no-index if git grep is
           executed outside of a git repository. Defaults to false.

       gpg.program
           Use this custom program instead of "ggppgg" found on $$PPAATTHH when making
           or verifying a PGP signature. The program must support the same
           command-line interface as GPG, namely, to verify a detached
           signature, "ggppgg ----vveerriiffyy $$ffiillee -- <<$$ssiiggnnaattuurree" is run, and the
           program is expected to signal a good signature by exiting with code
           0, and to generate an ASCII-armored detached signature, the
           standard input of "ggppgg --bbssaauu $$kkeeyy" is fed with the contents to be
           signed, and the program is expected to send the result to its
           standard output.

       gui.commitMsgWidth
           Defines how wide the commit message window is in the ggiitt--gguuii(1).
           "75" is the default.

       gui.diffContext
           Specifies how many context lines should be used in calls to diff
           made by the ggiitt--gguuii(1). The default is "5".

       gui.displayUntracked
           Determines if ggiitt--gguuii(1) shows untracked files in the file list.
           The default is "true".

       gui.encoding
           Specifies the default encoding to use for displaying of file
           contents in ggiitt--gguuii(1) and ggiittkk(1). It can be overridden by setting
           the _e_n_c_o_d_i_n_g attribute for relevant files (see ggiittaattttrriibbuutteess(5)).
           If this option is not set, the tools default to the locale
           encoding.

       gui.matchTrackingBranch
           Determines if new branches created with ggiitt--gguuii(1) should default
           to tracking remote branches with matching names or not. Default:
           "false".

       gui.newBranchTemplate
           Is used as suggested name when creating new branches using the ggiitt--
           gguuii(1).

       gui.pruneDuringFetch
           "true" if ggiitt--gguuii(1) should prune remote-tracking branches when
           performing a fetch. The default value is "false".

       gui.trustmtime
           Determines if ggiitt--gguuii(1) should trust the file modification
           timestamp or not. By default the timestamps are not trusted.

       gui.spellingDictionary
           Specifies the dictionary used for spell checking commit messages in
           the ggiitt--gguuii(1). When set to "none" spell checking is turned off.

       gui.fastCopyBlame
           If true, _g_i_t _g_u_i _b_l_a_m_e uses --CC instead of --CC --CC for original
           location detection. It makes blame significantly faster on huge
           repositories at the expense of less thorough copy detection.

       gui.copyBlameThreshold
           Specifies the threshold to use in _g_i_t _g_u_i _b_l_a_m_e original location
           detection, measured in alphanumeric characters. See the ggiitt--
           bbllaammee(1) manual for more information on copy detection.

       gui.blamehistoryctx
           Specifies the radius of history context in days to show in ggiittkk(1)
           for the selected commit, when the SShhooww HHiissttoorryy CCoonntteexxtt menu item is
           invoked from _g_i_t _g_u_i _b_l_a_m_e. If this variable is set to zero, the
           whole history is shown.

       guitool.<name>.cmd
           Specifies the shell command line to execute when the corresponding
           item of the ggiitt--gguuii(1)TToooollss menu is invoked. This option is
           mandatory for every tool. The command is executed from the root of
           the working directory, and in the environment it receives the name
           of the tool as GGIITT__GGUUIITTOOOOLL, the name of the currently selected file
           as _F_I_L_E_N_A_M_E, and the name of the current branch as _C_U_R___B_R_A_N_C_H (if
           the head is detached, _C_U_R___B_R_A_N_C_H is empty).

       guitool.<name>.needsFile
           Run the tool only if a diff is selected in the GUI. It guarantees
           that _F_I_L_E_N_A_M_E is not empty.

       guitool.<name>.noConsole
           Run the command silently, without creating a window to display its
           output.

       guitool.<name>.noRescan
           Don’t rescan the working directory for changes after the tool
           finishes execution.

       guitool.<name>.confirm
           Show a confirmation dialog before actually running the tool.

       guitool.<name>.argPrompt
           Request a string argument from the user, and pass it to the tool
           through the AARRGGSS environment variable. Since requesting an argument
           implies confirmation, the _c_o_n_f_i_r_m option has no effect if this is
           enabled. If the option is set to _t_r_u_e, _y_e_s, or _1, the dialog uses a
           built-in generic prompt; otherwise the exact value of the variable
           is used.

       guitool.<name>.revPrompt
           Request a single valid revision from the user, and set the RREEVVIISSIIOONN
           environment variable. In other aspects this option is similar to
           _a_r_g_P_r_o_m_p_t, and can be used together with it.

       guitool.<name>.revUnmerged
           Show only unmerged branches in the _r_e_v_P_r_o_m_p_t subdialog. This is
           useful for tools similar to merge or rebase, but not for things
           like checkout or reset.

       guitool.<name>.title
           Specifies the title to use for the prompt dialog. The default is
           the tool name.

       guitool.<name>.prompt
           Specifies the general prompt string to display at the top of the
           dialog, before subsections for _a_r_g_P_r_o_m_p_t and _r_e_v_P_r_o_m_p_t. The default
           value includes the actual command.

       help.browser
           Specify the browser that will be used to display help in the _w_e_b
           format. See ggiitt--hheellpp(1).

       help.format
           Override the default help format used by ggiitt--hheellpp(1). Values _m_a_n,
           _i_n_f_o, _w_e_b and _h_t_m_l are supported.  _m_a_n is the default.  _w_e_b and
           _h_t_m_l are the same.

       help.autoCorrect
           Automatically correct and execute mistyped commands after waiting
           for the given number of deciseconds (0.1 sec). If more than one
           command can be deduced from the entered text, nothing will be
           executed. If the value of this option is negative, the corrected
           command will be executed immediately. If the value is 0 - the
           command will be just shown but not executed. This is the default.

       help.htmlPath
           Specify the path where the HTML documentation resides. File system
           paths and URLs are supported. HTML pages will be prefixed with this
           path when help is displayed in the _w_e_b format. This defaults to the
           documentation path of your Git installation.

       http.proxy
           Override the HTTP proxy, normally configured using the _h_t_t_p___p_r_o_x_y,
           _h_t_t_p_s___p_r_o_x_y, and _a_l_l___p_r_o_x_y environment variables (see ccuurrll((11))). In
           addition to the syntax understood by curl, it is possible to
           specify a proxy string with a user name but no password, in which
           case git will attempt to acquire one in the same way it does for
           other credentials. See ggiittccrreeddeennttiiaallss(7) for more information. The
           syntax thus is _[_p_r_o_t_o_c_o_l_:_/_/_]_[_u_s_e_r_[_:_p_a_s_s_w_o_r_d_]_@_]_p_r_o_x_y_h_o_s_t_[_:_p_o_r_t_].
           This can be overridden on a per-remote basis; see
           remote.<name>.proxy

       http.proxyAuthMethod
           Set the method with which to authenticate against the HTTP proxy.
           This only takes effect if the configured proxy string contains a
           user name part (i.e. is of the form _u_s_e_r_@_h_o_s_t or _u_s_e_r_@_h_o_s_t_:_p_o_r_t).
           This can be overridden on a per-remote basis; see
           rreemmoottee..<<nnaammee>>..pprrooxxyyAAuutthhMMeetthhoodd. Both can be overridden by the
           GGIITT__HHTTTTPP__PPRROOXXYY__AAUUTTHHMMEETTHHOODD environment variable. Possible values
           are:

           ·   aannyyaauutthh - Automatically pick a suitable authentication method.
               It is assumed that the proxy answers an unauthenticated request
               with a 407 status code and one or more Proxy-authenticate
               headers with supported authentication methods. This is the
               default.

           ·   bbaassiicc - HTTP Basic authentication

           ·   ddiiggeesstt - HTTP Digest authentication; this prevents the password
               from being transmitted to the proxy in clear text

           ·   nneeggoottiiaattee - GSS-Negotiate authentication (compare the
               --negotiate option of ccuurrll((11)))

           ·   nnttllmm - NTLM authentication (compare the --ntlm option of
               ccuurrll((11)))

       http.emptyAuth
           Attempt authentication without seeking a username or password. This
           can be used to attempt GSS-Negotiate authentication without
           specifying a username in the URL, as libcurl normally requires a
           username for authentication.

       http.delegation
           Control GSSAPI credential delegation. The delegation is disabled by
           default in libcurl since version 7.21.7. Set parameter to tell the
           server what it is allowed to delegate when it comes to user
           credentials. Used with GSS/kerberos. Possible values are:

           ·   nnoonnee - Don’t allow any delegation.

           ·   ppoolliiccyy - Delegates if and only if the OK-AS-DELEGATE flag is
               set in the Kerberos service ticket, which is a matter of realm
               policy.

           ·   aallwwaayyss - Unconditionally allow the server to delegate.

       http.extraHeader
           Pass an additional HTTP header when communicating with a server. If
           more than one such entry exists, all of them are added as extra
           headers. To allow overriding the settings inherited from the system
           config, an empty value will reset the extra headers to the empty
           list.

       http.cookieFile
           The pathname of a file containing previously stored cookie lines,
           which should be used in the Git http session, if they match the
           server. The file format of the file to read cookies from should be
           plain HTTP headers or the Netscape/Mozilla cookie file format (see
           ccuurrll((11))). NOTE that the file specified with http.cookieFile is used
           only as input unless http.saveCookies is set.

       http.saveCookies
           If set, store cookies received during requests to the file
           specified by http.cookieFile. Has no effect if http.cookieFile is
           unset.

       http.sslVersion
           The SSL version to use when negotiating an SSL connection, if you
           want to force the default. The available and default version depend
           on whether libcurl was built against NSS or OpenSSL and the
           particular configuration of the crypto library in use. Internally
           this sets the _C_U_R_L_O_P_T___S_S_L___V_E_R_S_I_O_N option; see the libcurl
           documentation for more details on the format of this option and for
           the ssl version supported. Actually the possible values of this
           option are:

           ·   sslv2

           ·   sslv3

           ·   tlsv1

           ·   tlsv1.0

           ·   tlsv1.1

           ·   tlsv1.2

           Can be overridden by the GGIITT__SSSSLL__VVEERRSSIIOONN environment variable. To
           force git to use libcurl’s default ssl version and ignore any
           explicit http.sslversion option, set GGIITT__SSSSLL__VVEERRSSIIOONN to the empty
           string.

       http.sslCipherList
           A list of SSL ciphers to use when negotiating an SSL connection.
           The available ciphers depend on whether libcurl was built against
           NSS or OpenSSL and the particular configuration of the crypto
           library in use. Internally this sets the _C_U_R_L_O_P_T___S_S_L___C_I_P_H_E_R___L_I_S_T
           option; see the libcurl documentation for more details on the
           format of this list.

           Can be overridden by the GGIITT__SSSSLL__CCIIPPHHEERR__LLIISSTT environment variable.
           To force git to use libcurl’s default cipher list and ignore any
           explicit http.sslCipherList option, set GGIITT__SSSSLL__CCIIPPHHEERR__LLIISSTT to the
           empty string.

       http.sslVerify
           Whether to verify the SSL certificate when fetching or pushing over
           HTTPS. Can be overridden by the GGIITT__SSSSLL__NNOO__VVEERRIIFFYY environment
           variable.

       http.sslCert
           File containing the SSL certificate when fetching or pushing over
           HTTPS. Can be overridden by the GGIITT__SSSSLL__CCEERRTT environment variable.

       http.sslKey
           File containing the SSL private key when fetching or pushing over
           HTTPS. Can be overridden by the GGIITT__SSSSLL__KKEEYY environment variable.

       http.sslCertPasswordProtected
           Enable Git’s password prompt for the SSL certificate. Otherwise
           OpenSSL will prompt the user, possibly many times, if the
           certificate or private key is encrypted. Can be overridden by the
           GGIITT__SSSSLL__CCEERRTT__PPAASSSSWWOORRDD__PPRROOTTEECCTTEEDD environment variable.

       http.sslCAInfo
           File containing the certificates to verify the peer with when
           fetching or pushing over HTTPS. Can be overridden by the
           GGIITT__SSSSLL__CCAAIINNFFOO environment variable.

       http.sslCAPath
           Path containing files with the CA certificates to verify the peer
           with when fetching or pushing over HTTPS. Can be overridden by the
           GGIITT__SSSSLL__CCAAPPAATTHH environment variable.

       http.pinnedpubkey
           Public key of the https service. It may either be the filename of a
           PEM or DER encoded public key file or a string starting with
           _s_h_a_2_5_6_/_/ followed by the base64 encoded sha256 hash of the public
           key. See also libcurl _C_U_R_L_O_P_T___P_I_N_N_E_D_P_U_B_L_I_C_K_E_Y. git will exit with
           an error if this option is set but not supported by cURL.

       http.sslTry
           Attempt to use AUTH SSL/TLS and encrypted data transfers when
           connecting via regular FTP protocol. This might be needed if the
           FTP server requires it for security reasons or you wish to connect
           securely whenever remote FTP server supports it. Default is false
           since it might trigger certificate verification errors on
           misconfigured servers.

       http.maxRequests
           How many HTTP requests to launch in parallel. Can be overridden by
           the GGIITT__HHTTTTPP__MMAAXX__RREEQQUUEESSTTSS environment variable. Default is 5.

       http.minSessions
           The number of curl sessions (counted across slots) to be kept
           across requests. They will not be ended with curl_easy_cleanup()
           until http_cleanup() is invoked. If USE_CURL_MULTI is not defined,
           this value will be capped at 1. Defaults to 1.

       http.postBuffer
           Maximum size in bytes of the buffer used by smart HTTP transports
           when POSTing data to the remote system. For requests larger than
           this buffer size, HTTP/1.1 and Transfer-Encoding: chunked is used
           to avoid creating a massive pack file locally. Default is 1 MiB,
           which is sufficient for most requests.

       http.lowSpeedLimit, http.lowSpeedTime
           If the HTTP transfer speed is less than _h_t_t_p_._l_o_w_S_p_e_e_d_L_i_m_i_t for
           longer than _h_t_t_p_._l_o_w_S_p_e_e_d_T_i_m_e seconds, the transfer is aborted. Can
           be overridden by the GGIITT__HHTTTTPP__LLOOWW__SSPPEEEEDD__LLIIMMIITT and
           GGIITT__HHTTTTPP__LLOOWW__SSPPEEEEDD__TTIIMMEE environment variables.

       http.noEPSV
           A boolean which disables using of EPSV ftp command by curl. This
           can helpful with some "poor" ftp servers which don’t support EPSV
           mode. Can be overridden by the GGIITT__CCUURRLL__FFTTPP__NNOO__EEPPSSVV environment
           variable. Default is false (curl will use EPSV).

       http.userAgent
           The HTTP USER_AGENT string presented to an HTTP server. The default
           value represents the version of the client Git such as git/1.7.1.
           This option allows you to override this value to a more common
           value such as Mozilla/4.0. This may be necessary, for instance, if
           connecting through a firewall that restricts HTTP connections to a
           set of common USER_AGENT strings (but not including those like
           git/1.7.1). Can be overridden by the GGIITT__HHTTTTPP__UUSSEERR__AAGGEENNTT
           environment variable.

       http.followRedirects
           Whether git should follow HTTP redirects. If set to ttrruuee, git will
           transparently follow any redirect issued by a server it encounters.
           If set to ffaallssee, git will treat all redirects as errors. If set to
           iinniittiiaall, git will follow redirects only for the initial request to
           a remote, but not for subsequent follow-up HTTP requests. Since git
           uses the redirected URL as the base for the follow-up requests,
           this is generally sufficient. The default is iinniittiiaall.

       http.<url>.*
           Any of the http.* options above can be applied selectively to some
           URLs. For a config key to match a URL, each element of the config
           key is compared to that of the URL, in the following order:

            1. Scheme (e.g., hhttttppss in hhttttppss::////eexxaammppllee..ccoomm//). This field must
               match exactly between the config key and the URL.

            2. Host/domain name (e.g., eexxaammppllee..ccoomm in hhttttppss::////eexxaammppllee..ccoomm//).
               This field must match between the config key and the URL. It is
               possible to specify a ** as part of the host name to match all
               subdomains at this level.  hhttttppss::////**..eexxaammppllee..ccoomm// for example
               would match hhttttppss::////ffoooo..eexxaammppllee..ccoomm//, but not
               hhttttppss::////ffoooo..bbaarr..eexxaammppllee..ccoomm//.

            3. Port number (e.g., 88008800 in hhttttpp::////eexxaammppllee..ccoomm::88008800//). This
               field must match exactly between the config key and the URL.
               Omitted port numbers are automatically converted to the correct
               default for the scheme before matching.

            4. Path (e.g., rreeppoo..ggiitt in hhttttppss::////eexxaammppllee..ccoomm//rreeppoo..ggiitt). The path
               field of the config key must match the path field of the URL
               either exactly or as a prefix of slash-delimited path elements.
               This means a config key with path ffoooo// matches URL path
               ffoooo//bbaarr. A prefix can only match on a slash (//) boundary.
               Longer matches take precedence (so a config key with path
               ffoooo//bbaarr is a better match to URL path ffoooo//bbaarr than a config key
               with just path ffoooo//).

            5. User name (e.g., uusseerr in hhttttppss::////uusseerr@@eexxaammppllee..ccoomm//rreeppoo..ggiitt). If
               the config key has a user name it must match the user name in
               the URL exactly. If the config key does not have a user name,
               that config key will match a URL with any user name (including
               none), but at a lower precedence than a config key with a user
               name.

           The list above is ordered by decreasing precedence; a URL that
           matches a config key’s path is preferred to one that matches its
           user name. For example, if the URL is
           hhttttppss::////uusseerr@@eexxaammppllee..ccoomm//ffoooo//bbaarr a config key match of
           hhttttppss::////eexxaammppllee..ccoomm//ffoooo will be preferred over a config key match
           of hhttttppss::////uusseerr@@eexxaammppllee..ccoomm.

           All URLs are normalized before attempting any matching (the
           password part, if embedded in the URL, is always ignored for
           matching purposes) so that equivalent URLs that are simply spelled
           differently will match properly. Environment variable settings
           always override any matches. The URLs that are matched against are
           those given directly to Git commands. This means any URLs visited
           as a result of a redirection do not participate in matching.

       ssh.variant
           Depending on the value of the environment variables GGIITT__SSSSHH or
           GGIITT__SSSSHH__CCOOMMMMAANNDD, or the config setting ccoorree..sssshhCCoommmmaanndd, Git
           auto-detects whether to adjust its command-line parameters for use
           with plink or tortoiseplink, as opposed to the default (OpenSSH).

           The config variable sssshh..vvaarriiaanntt can be set to override this
           auto-detection; valid values are sssshh, pplliinnkk, ppuuttttyy or
           ttoorrttooiisseepplliinnkk. Any other value will be treated as normal ssh. This
           setting can be overridden via the environment variable
           GGIITT__SSSSHH__VVAARRIIAANNTT.

       i18n.commitEncoding
           Character encoding the commit messages are stored in; Git itself
           does not care per se, but this information is necessary e.g. when
           importing commits from emails or in the gitk graphical history
           browser (and possibly at other places in the future or in other
           porcelains). See e.g.  ggiitt--mmaaiilliinnffoo(1). Defaults to _u_t_f_-_8.

       i18n.logOutputEncoding
           Character encoding the commit messages are converted to when
           running _g_i_t _l_o_g and friends.

       imap
           The configuration variables in the _i_m_a_p section are described in
           ggiitt--iimmaapp--sseenndd(1).

       index.version
           Specify the version with which new index files should be
           initialized. This does not affect existing repositories.

       init.templateDir
           Specify the directory from which templates will be copied. (See the
           "TEMPLATE DIRECTORY" section of ggiitt--iinniitt(1).)

       instaweb.browser
           Specify the program that will be used to browse your working
           repository in gitweb. See ggiitt--iinnssttaawweebb(1).

       instaweb.httpd
           The HTTP daemon command-line to start gitweb on your working
           repository. See ggiitt--iinnssttaawweebb(1).

       instaweb.local
           If true the web server started by ggiitt--iinnssttaawweebb(1) will be bound to
           the local IP (127.0.0.1).

       instaweb.modulePath
           The default module path for ggiitt--iinnssttaawweebb(1) to use instead of
           /usr/lib/apache2/modules. Only used if httpd is Apache.

       instaweb.port
           The port number to bind the gitweb httpd to. See ggiitt--iinnssttaawweebb(1).

       interactive.singleKey
           In interactive commands, allow the user to provide one-letter input
           with a single key (i.e., without hitting enter). Currently this is
           used by the ----ppaattcchh mode of ggiitt--aadddd(1), ggiitt--cchheecckkoouutt(1), ggiitt--
           ccoommmmiitt(1), ggiitt--rreesseett(1), and ggiitt--ssttaasshh(1). Note that this setting
           is silently ignored if portable keystroke input is not available;
           requires the Perl module Term::ReadKey.

       interactive.diffFilter
           When an interactive command (such as ggiitt aadddd ----ppaattcchh) shows a
           colorized diff, git will pipe the diff through the shell command
           defined by this configuration variable. The command may mark up the
           diff further for human consumption, provided that it retains a
           one-to-one correspondence with the lines in the original diff.
           Defaults to disabled (no filtering).

       log.abbrevCommit
           If true, makes ggiitt--lloogg(1), ggiitt--sshhooww(1), and ggiitt--wwhhaattcchhaannggeedd(1)
           assume ----aabbbbrreevv--ccoommmmiitt. You may override this option with
           ----nnoo--aabbbbrreevv--ccoommmmiitt.

       log.date
           Set the default date-time mode for the _l_o_g command. Setting a value
           for log.date is similar to using _g_i_t _l_o_g's ----ddaattee option. See ggiitt--
           lloogg(1) for details.

       log.decorate
           Print out the ref names of any commits that are shown by the log
           command. If _s_h_o_r_t is specified, the ref name prefixes _r_e_f_s_/_h_e_a_d_s_/,
           _r_e_f_s_/_t_a_g_s_/ and _r_e_f_s_/_r_e_m_o_t_e_s_/ will not be printed. If _f_u_l_l is
           specified, the full ref name (including prefix) will be printed. If
           _a_u_t_o is specified, then if the output is going to a terminal, the
           ref names are shown as if _s_h_o_r_t were given, otherwise no ref names
           are shown. This is the same as the ----ddeeccoorraattee option of the ggiitt
           lloogg.

       log.follow
           If ttrruuee, ggiitt lloogg will act as if the ----ffoollllooww option was used when a
           single <path> is given. This has the same limitations as ----ffoollllooww,
           i.e. it cannot be used to follow multiple files and does not work
           well on non-linear history.

       log.graphColors
           A list of colors, separated by commas, that can be used to draw
           history lines in ggiitt lloogg ----ggrraapphh.

       log.showRoot
           If true, the initial commit will be shown as a big creation event.
           This is equivalent to a diff against an empty tree. Tools like ggiitt--
           lloogg(1) or ggiitt--wwhhaattcchhaannggeedd(1), which normally hide the root commit
           will now show it. True by default.

       log.showSignature
           If true, makes ggiitt--lloogg(1), ggiitt--sshhooww(1), and ggiitt--wwhhaattcchhaannggeedd(1)
           assume ----sshhooww--ssiiggnnaattuurree.

       log.mailmap
           If true, makes ggiitt--lloogg(1), ggiitt--sshhooww(1), and ggiitt--wwhhaattcchhaannggeedd(1)
           assume ----uussee--mmaaiillmmaapp.

       mailinfo.scissors
           If true, makes ggiitt--mmaaiilliinnffoo(1) (and therefore ggiitt--aamm(1)) act by
           default as if the --scissors option was provided on the
           command-line. When active, this features removes everything from
           the message body before a scissors line (i.e. consisting mainly of
           ">8", "8<" and "-").

       mailmap.file
           The location of an augmenting mailmap file. The default mailmap,
           located in the root of the repository, is loaded first, then the
           mailmap file pointed to by this variable. The location of the
           mailmap file may be in a repository subdirectory, or somewhere
           outside of the repository itself. See ggiitt--sshhoorrttlloogg(1) and ggiitt--
           bbllaammee(1).

       mailmap.blob
           Like mmaaiillmmaapp..ffiillee, but consider the value as a reference to a blob
           in the repository. If both mmaaiillmmaapp..ffiillee and mmaaiillmmaapp..bblloobb are given,
           both are parsed, with entries from mmaaiillmmaapp..ffiillee taking precedence.
           In a bare repository, this defaults to HHEEAADD::..mmaaiillmmaapp. In a non-bare
           repository, it defaults to empty.

       man.viewer
           Specify the programs that may be used to display help in the _m_a_n
           format. See ggiitt--hheellpp(1).

       man.<tool>.cmd
           Specify the command to invoke the specified man viewer. The
           specified command is evaluated in shell with the man page passed as
           argument. (See ggiitt--hheellpp(1).)

       man.<tool>.path
           Override the path for the given tool that may be used to display
           help in the _m_a_n format. See ggiitt--hheellpp(1).

       merge.conflictStyle
           Specify the style in which conflicted hunks are written out to
           working tree files upon merge. The default is "merge", which shows
           a <<<<<<<<<<<<<< conflict marker, changes made by one side, a ==============
           marker, changes made by the other side, and then a >>>>>>>>>>>>>> marker.
           An alternate style, "diff3", adds a |||||||||||||| marker and the original
           text before the ============== marker.

       merge.defaultToUpstream
           If merge is called without any commit argument, merge the upstream
           branches configured for the current branch by using their last
           observed values stored in their remote-tracking branches. The
           values of the bbrraanncchh..<<ccuurrrreenntt bbrraanncchh>>..mmeerrggee that name the branches
           at the remote named by bbrraanncchh..<<ccuurrrreenntt bbrraanncchh>>..rreemmoottee are
           consulted, and then they are mapped via rreemmoottee..<<rreemmoottee>>..ffeettcchh to
           their corresponding remote-tracking branches, and the tips of these
           tracking branches are merged.

       merge.ff
           By default, Git does not create an extra merge commit when merging
           a commit that is a descendant of the current commit. Instead, the
           tip of the current branch is fast-forwarded. When set to ffaallssee,
           this variable tells Git to create an extra merge commit in such a
           case (equivalent to giving the ----nnoo--ffff option from the command
           line). When set to oonnllyy, only such fast-forward merges are allowed
           (equivalent to giving the ----ffff--oonnllyy option from the command line).

       merge.branchdesc
           In addition to branch names, populate the log message with the
           branch description text associated with them. Defaults to false.

       merge.log
           In addition to branch names, populate the log message with at most
           the specified number of one-line descriptions from the actual
           commits that are being merged. Defaults to false, and true is a
           synonym for 20.

       merge.renameLimit
           The number of files to consider when performing rename detection
           during a merge; if not specified, defaults to the value of
           diff.renameLimit.

       merge.renormalize
           Tell Git that canonical representation of files in the repository
           has changed over time (e.g. earlier commits record text files with
           CRLF line endings, but recent ones use LF line endings). In such a
           repository, Git can convert the data recorded in commits to a
           canonical form before performing a merge to reduce unnecessary
           conflicts. For more information, see section "Merging branches with
           differing checkin/checkout attributes" in ggiittaattttrriibbuutteess(5).

       merge.stat
           Whether to print the diffstat between ORIG_HEAD and the merge
           result at the end of the merge. True by default.

       merge.tool
           Controls which merge tool is used by ggiitt--mmeerrggeettooooll(1). The list
           below shows the valid built-in values. Any other value is treated
           as a custom merge tool and requires that a corresponding
           mergetool.<tool>.cmd variable is defined.

           ·   araxis

           ·   bc

           ·   bc3

           ·   codecompare

           ·   deltawalker

           ·   diffmerge

           ·   diffuse

           ·   ecmerge

           ·   emerge

           ·   examdiff

           ·   gvimdiff

           ·   gvimdiff2

           ·   gvimdiff3

           ·   kdiff3

           ·   meld

           ·   opendiff

           ·   p4merge

           ·   tkdiff

           ·   tortoisemerge

           ·   vimdiff

           ·   vimdiff2

           ·   vimdiff3

           ·   winmerge

           ·   xxdiff

       merge.verbosity
           Controls the amount of output shown by the recursive merge
           strategy. Level 0 outputs nothing except a final error message if
           conflicts were detected. Level 1 outputs only conflicts, 2 outputs
           conflicts and file changes. Level 5 and above outputs debugging
           information. The default is level 2. Can be overridden by the
           GGIITT__MMEERRGGEE__VVEERRBBOOSSIITTYY environment variable.

       merge.<driver>.name
           Defines a human-readable name for a custom low-level merge driver.
           See ggiittaattttrriibbuutteess(5) for details.

       merge.<driver>.driver
           Defines the command that implements a custom low-level merge
           driver. See ggiittaattttrriibbuutteess(5) for details.

       merge.<driver>.recursive
           Names a low-level merge driver to be used when performing an
           internal merge between common ancestors. See ggiittaattttrriibbuutteess(5) for
           details.

       mergetool.<tool>.path
           Override the path for the given tool. This is useful in case your
           tool is not in the PATH.

       mergetool.<tool>.cmd
           Specify the command to invoke the specified merge tool. The
           specified command is evaluated in shell with the following
           variables available: _B_A_S_E is the name of a temporary file
           containing the common base of the files to be merged, if available;
           _L_O_C_A_L is the name of a temporary file containing the contents of
           the file on the current branch; _R_E_M_O_T_E is the name of a temporary
           file containing the contents of the file from the branch being
           merged; _M_E_R_G_E_D contains the name of the file to which the merge
           tool should write the results of a successful merge.

       mergetool.<tool>.trustExitCode
           For a custom merge command, specify whether the exit code of the
           merge command can be used to determine whether the merge was
           successful. If this is not set to true then the merge target file
           timestamp is checked and the merge assumed to have been successful
           if the file has been updated, otherwise the user is prompted to
           indicate the success of the merge.

       mergetool.meld.hasOutput
           Older versions of mmeelldd do not support the ----oouuttppuutt option. Git will
           attempt to detect whether mmeelldd supports ----oouuttppuutt by inspecting the
           output of mmeelldd ----hheellpp. Configuring mmeerrggeettooooll..mmeelldd..hhaassOOuuttppuutt will
           make Git skip these checks and use the configured value instead.
           Setting mmeerrggeettooooll..mmeelldd..hhaassOOuuttppuutt to ttrruuee tells Git to
           unconditionally use the ----oouuttppuutt option, and ffaallssee avoids using
           ----oouuttppuutt.

       mergetool.keepBackup
           After performing a merge, the original file with conflict markers
           can be saved as a file with a ..oorriigg extension. If this variable is
           set to ffaallssee then this file is not preserved. Defaults to ttrruuee
           (i.e. keep the backup files).

       mergetool.keepTemporaries
           When invoking a custom merge tool, Git uses a set of temporary
           files to pass to the tool. If the tool returns an error and this
           variable is set to ttrruuee, then these temporary files will be
           preserved, otherwise they will be removed after the tool has
           exited. Defaults to ffaallssee.

       mergetool.writeToTemp
           Git writes temporary _B_A_S_E, _L_O_C_A_L, and _R_E_M_O_T_E versions of
           conflicting files in the worktree by default. Git will attempt to
           use a temporary directory for these files when set ttrruuee. Defaults
           to ffaallssee.

       mergetool.prompt
           Prompt before each invocation of the merge resolution program.

       notes.mergeStrategy
           Which merge strategy to choose by default when resolving notes
           conflicts. Must be one of mmaannuuaall, oouurrss, tthheeiirrss, uunniioonn, or
           ccaatt__ssoorrtt__uunniiqq. Defaults to mmaannuuaall. See "NOTES MERGE STRATEGIES"
           section of ggiitt--nnootteess(1) for more information on each strategy.

       notes.<name>.mergeStrategy
           Which merge strategy to choose when doing a notes merge into
           refs/notes/<name>. This overrides the more general
           "notes.mergeStrategy". See the "NOTES MERGE STRATEGIES" section in
           ggiitt--nnootteess(1) for more information on the available strategies.

       notes.displayRef
           The (fully qualified) refname from which to show notes when showing
           commit messages. The value of this variable can be set to a glob,
           in which case notes from all matching refs will be shown. You may
           also specify this configuration variable several times. A warning
           will be issued for refs that do not exist, but a glob that does not
           match any refs is silently ignored.

           This setting can be overridden with the GGIITT__NNOOTTEESS__DDIISSPPLLAAYY__RREEFF
           environment variable, which must be a colon separated list of refs
           or globs.

           The effective value of "core.notesRef" (possibly overridden by
           GIT_NOTES_REF) is also implicitly added to the list of refs to be
           displayed.

       notes.rewrite.<command>
           When rewriting commits with <command> (currently aammeenndd or rreebbaassee)
           and this variable is set to ttrruuee, Git automatically copies your
           notes from the original to the rewritten commit. Defaults to ttrruuee,
           but see "notes.rewriteRef" below.

       notes.rewriteMode
           When copying notes during a rewrite (see the
           "notes.rewrite.<command>" option), determines what to do if the
           target commit already has a note. Must be one of oovveerrwwrriittee,
           ccoonnccaatteennaattee, ccaatt__ssoorrtt__uunniiqq, or iiggnnoorree. Defaults to ccoonnccaatteennaattee.

           This setting can be overridden with the GGIITT__NNOOTTEESS__RREEWWRRIITTEE__MMOODDEE
           environment variable.

       notes.rewriteRef
           When copying notes during a rewrite, specifies the (fully
           qualified) ref whose notes should be copied. The ref may be a glob,
           in which case notes in all matching refs will be copied. You may
           also specify this configuration several times.

           Does not have a default value; you must configure this variable to
           enable note rewriting. Set it to rreeffss//nnootteess//ccoommmmiittss to enable
           rewriting for the default commit notes.

           This setting can be overridden with the GGIITT__NNOOTTEESS__RREEWWRRIITTEE__RREEFF
           environment variable, which must be a colon separated list of refs
           or globs.

       pack.window
           The size of the window used by ggiitt--ppaacckk--oobbjjeeccttss(1) when no window
           size is given on the command line. Defaults to 10.

       pack.depth
           The maximum delta depth used by ggiitt--ppaacckk--oobbjjeeccttss(1) when no maximum
           depth is given on the command line. Defaults to 50.

       pack.windowMemory
           The maximum size of memory that is consumed by each thread in ggiitt--
           ppaacckk--oobbjjeeccttss(1) for pack window memory when no limit is given on
           the command line. The value can be suffixed with "k", "m", or "g".
           When left unconfigured (or set explicitly to 0), there will be no
           limit.

       pack.compression
           An integer -1..9, indicating the compression level for objects in a
           pack file. -1 is the zlib default. 0 means no compression, and 1..9
           are various speed/size tradeoffs, 9 being slowest. If not set,
           defaults to core.compression. If that is not set, defaults to -1,
           the zlib default, which is "a default compromise between speed and
           compression (currently equivalent to level 6)."

           Note that changing the compression level will not automatically
           recompress all existing objects. You can force recompression by
           passing the -F option to ggiitt--rreeppaacckk(1).

       pack.deltaCacheSize
           The maximum memory in bytes used for caching deltas in ggiitt--ppaacckk--
           oobbjjeeccttss(1) before writing them out to a pack. This cache is used to
           speed up the writing object phase by not having to recompute the
           final delta result once the best match for all objects is found.
           Repacking large repositories on machines which are tight with
           memory might be badly impacted by this though, especially if this
           cache pushes the system into swapping. A value of 0 means no limit.
           The smallest size of 1 byte may be used to virtually disable this
           cache. Defaults to 256 MiB.

       pack.deltaCacheLimit
           The maximum size of a delta, that is cached in ggiitt--ppaacckk--oobbjjeeccttss(1).
           This cache is used to speed up the writing object phase by not
           having to recompute the final delta result once the best match for
           all objects is found. Defaults to 1000.

       pack.threads
           Specifies the number of threads to spawn when searching for best
           delta matches. This requires that ggiitt--ppaacckk--oobbjjeeccttss(1) be compiled
           with pthreads otherwise this option is ignored with a warning. This
           is meant to reduce packing time on multiprocessor machines. The
           required amount of memory for the delta search window is however
           multiplied by the number of threads. Specifying 0 will cause Git to
           auto-detect the number of CPU’s and set the number of threads
           accordingly.

       pack.indexVersion
           Specify the default pack index version. Valid values are 1 for
           legacy pack index used by Git versions prior to 1.5.2, and 2 for
           the new pack index with capabilities for packs larger than 4 GB as
           well as proper protection against the repacking of corrupted packs.
           Version 2 is the default. Note that version 2 is enforced and this
           config option ignored whenever the corresponding pack is larger
           than 2 GB.

           If you have an old Git that does not understand the version 2 **..iiddxx
           file, cloning or fetching over a non native protocol (e.g. "http")
           that will copy both **..ppaacckk file and corresponding **..iiddxx file from
           the other side may give you a repository that cannot be accessed
           with your older version of Git. If the **..ppaacckk file is smaller than
           2 GB, however, you can use ggiitt--iinnddeexx--ppaacckk(1) on the *.pack file to
           regenerate the **..iiddxx file.

       pack.packSizeLimit
           The maximum size of a pack. This setting only affects packing to a
           file when repacking, i.e. the git:// protocol is unaffected. It can
           be overridden by the ----mmaaxx--ppaacckk--ssiizzee option of ggiitt--rreeppaacckk(1).
           Reaching this limit results in the creation of multiple packfiles;
           which in turn prevents bitmaps from being created. The minimum size
           allowed is limited to 1 MiB. The default is unlimited. Common unit
           suffixes of _k, _m, or _g are supported.

       pack.useBitmaps
           When true, git will use pack bitmaps (if available) when packing to
           stdout (e.g., during the server side of a fetch). Defaults to true.
           You should not generally need to turn this off unless you are
           debugging pack bitmaps.

       pack.writeBitmaps (deprecated)
           This is a deprecated synonym for rreeppaacckk..wwrriitteeBBiittmmaappss.

       pack.writeBitmapHashCache
           When true, git will include a "hash cache" section in the bitmap
           index (if one is written). This cache can be used to feed git’s
           delta heuristics, potentially leading to better deltas between
           bitmapped and non-bitmapped objects (e.g., when serving a fetch
           between an older, bitmapped pack and objects that have been pushed
           since the last gc). The downside is that it consumes 4 bytes per
           object of disk space, and that JGit’s bitmap implementation does
           not understand it, causing it to complain if Git and JGit are used
           on the same repository. Defaults to false.

       pager.<cmd>
           If the value is boolean, turns on or off pagination of the output
           of a particular Git subcommand when writing to a tty. Otherwise,
           turns on pagination for the subcommand using the pager specified by
           the value of ppaaggeerr..<<ccmmdd>>. If ----ppaaggiinnaattee or ----nnoo--ppaaggeerr is specified
           on the command line, it takes precedence over this option. To
           disable pagination for all commands, set ccoorree..ppaaggeerr or GGIITT__PPAAGGEERR to
           ccaatt.

       pretty.<name>
           Alias for a --pretty= format string, as specified in ggiitt--lloogg(1).
           Any aliases defined here can be used just as the built-in pretty
           formats could. For example, running ggiitt ccoonnffiigg pprreettttyy..cchhaannggeelloogg
           ""ffoorrmmaatt::** %%HH %%ss"" would cause the invocation ggiitt lloogg
           ----pprreettttyy==cchhaannggeelloogg to be equivalent to running ggiitt lloogg
           ""----pprreettttyy==ffoorrmmaatt::** %%HH %%ss"". Note that an alias with the same name as
           a built-in format will be silently ignored.

       protocol.allow
           If set, provide a user defined default policy for all protocols
           which don’t explicitly have a policy (pprroottooccooll..<<nnaammee>>..aallllooww). By
           default, if unset, known-safe protocols (http, https, git, ssh,
           file) have a default policy of aallwwaayyss, known-dangerous protocols
           (ext) have a default policy of nneevveerr, and all other protocols have
           a default policy of uusseerr. Supported policies:

           ·   aallwwaayyss - protocol is always able to be used.

           ·   nneevveerr - protocol is never able to be used.

           ·   uusseerr - protocol is only able to be used when
               GGIITT__PPRROOTTOOCCOOLL__FFRROOMM__UUSSEERR is either unset or has a value of 1.
               This policy should be used when you want a protocol to be
               directly usable by the user but don’t want it used by commands
               which execute clone/fetch/push commands without user input,
               e.g. recursive submodule initialization.

       protocol.<name>.allow
           Set a policy to be used by protocol <<nnaammee>> with clone/fetch/push
           commands. See pprroottooccooll..aallllooww above for the available policies.

           The protocol names currently used by git are:

           ·   ffiillee: any local file-based path (including ffiillee:://// URLs, or
               local paths)

           ·   ggiitt: the anonymous git protocol over a direct TCP connection
               (or proxy, if configured)

           ·   sssshh: git over ssh (including hhoosstt::ppaatthh syntax, sssshh::////, etc).

           ·   hhttttpp: git over http, both "smart http" and "dumb http". Note
               that this does _n_o_t include hhttttppss; if you want to configure
               both, you must do so individually.

           ·   any external helpers are named by their protocol (e.g., use hhgg
               to allow the ggiitt--rreemmoottee--hhgg helper)

       pull.ff
           By default, Git does not create an extra merge commit when merging
           a commit that is a descendant of the current commit. Instead, the
           tip of the current branch is fast-forwarded. When set to ffaallssee,
           this variable tells Git to create an extra merge commit in such a
           case (equivalent to giving the ----nnoo--ffff option from the command
           line). When set to oonnllyy, only such fast-forward merges are allowed
           (equivalent to giving the ----ffff--oonnllyy option from the command line).
           This setting overrides mmeerrggee..ffff when pulling.

       pull.rebase
           When true, rebase branches on top of the fetched branch, instead of
           merging the default branch from the default remote when "git pull"
           is run. See "branch.<name>.rebase" for setting this on a per-branch
           basis.

           When preserve, also pass ----pprreesseerrvvee--mmeerrggeess along to _g_i_t _r_e_b_a_s_e so
           that locally committed merge commits will not be flattened by
           running _g_i_t _p_u_l_l.

           When the value is iinntteerraaccttiivvee, the rebase is run in interactive
           mode.

           NNOOTTEE: this is a possibly dangerous operation; do nnoott use it unless
           you understand the implications (see ggiitt--rreebbaassee(1) for details).

       pull.octopus
           The default merge strategy to use when pulling multiple branches at
           once.

       pull.twohead
           The default merge strategy to use when pulling a single branch.

       push.default
           Defines the action ggiitt ppuusshh should take if no refspec is explicitly
           given. Different values are well-suited for specific workflows; for
           instance, in a purely central workflow (i.e. the fetch source is
           equal to the push destination), uuppssttrreeaamm is probably what you want.
           Possible values are:

           ·   nnootthhiinngg - do not push anything (error out) unless a refspec is
               explicitly given. This is primarily meant for people who want
               to avoid mistakes by always being explicit.

           ·   ccuurrrreenntt - push the current branch to update a branch with the
               same name on the receiving end. Works in both central and
               non-central workflows.

           ·   uuppssttrreeaamm - push the current branch back to the branch whose
               changes are usually integrated into the current branch (which
               is called @@{{uuppssttrreeaamm}}). This mode only makes sense if you are
               pushing to the same repository you would normally pull from
               (i.e. central workflow).

           ·   ttrraacckkiinngg - This is a deprecated synonym for uuppssttrreeaamm.

           ·   ssiimmppllee - in centralized workflow, work like uuppssttrreeaamm with an
               added safety to refuse to push if the upstream branch’s name is
               different from the local one.

               When pushing to a remote that is different from the remote you
               normally pull from, work as ccuurrrreenntt. This is the safest option
               and is suited for beginners.

               This mode has become the default in Git 2.0.

           ·   mmaattcchhiinngg - push all branches having the same name on both ends.
               This makes the repository you are pushing to remember the set
               of branches that will be pushed out (e.g. if you always push
               _m_a_i_n_t and _m_a_s_t_e_r there and no other branches, the repository
               you push to will have these two branches, and your local _m_a_i_n_t
               and _m_a_s_t_e_r will be pushed there).

               To use this mode effectively, you have to make sure _a_l_l the
               branches you would push out are ready to be pushed out before
               running _g_i_t _p_u_s_h, as the whole point of this mode is to allow
               you to push all of the branches in one go. If you usually
               finish work on only one branch and push out the result, while
               other branches are unfinished, this mode is not for you. Also
               this mode is not suitable for pushing into a shared central
               repository, as other people may add new branches there, or
               update the tip of existing branches outside your control.

               This used to be the default, but not since Git 2.0 (ssiimmppllee is
               the new default).

       push.followTags
           If set to true enable ----ffoollllooww--ttaaggss option by default. You may
           override this configuration at time of push by specifying
           ----nnoo--ffoollllooww--ttaaggss.

       push.gpgSign
           May be set to a boolean value, or the string _i_f_-_a_s_k_e_d. A true value
           causes all pushes to be GPG signed, as if ----ssiiggnneedd is passed to
           ggiitt--ppuusshh(1). The string _i_f_-_a_s_k_e_d causes pushes to be signed if the
           server supports it, as if ----ssiiggnneedd==iiff--aasskkeedd is passed to _g_i_t _p_u_s_h.
           A false value may override a value from a lower-priority config
           file. An explicit command-line flag always overrides this config
           option.

       push.recurseSubmodules
           Make sure all submodule commits used by the revisions to be pushed
           are available on a remote-tracking branch. If the value is _c_h_e_c_k
           then Git will verify that all submodule commits that changed in the
           revisions to be pushed are available on at least one remote of the
           submodule. If any commits are missing, the push will be aborted and
           exit with non-zero status. If the value is _o_n_-_d_e_m_a_n_d then all
           submodules that changed in the revisions to be pushed will be
           pushed. If on-demand was not able to push all necessary revisions
           it will also be aborted and exit with non-zero status. If the value
           is _n_o then default behavior of ignoring submodules when pushing is
           retained. You may override this configuration at time of push by
           specifying _-_-_r_e_c_u_r_s_e_-_s_u_b_m_o_d_u_l_e_s_=_c_h_e_c_k_|_o_n_-_d_e_m_a_n_d_|_n_o.

       rebase.stat
           Whether to show a diffstat of what changed upstream since the last
           rebase. False by default.

       rebase.autoSquash
           If set to true enable ----aauuttoossqquuaasshh option by default.

       rebase.autoStash
           When set to true, automatically create a temporary stash before the
           operation begins, and apply it after the operation ends. This means
           that you can run rebase on a dirty worktree. However, use with
           care: the final stash application after a successful rebase might
           result in non-trivial conflicts. Defaults to false.

       rebase.missingCommitsCheck
           If set to "warn", git rebase -i will print a warning if some
           commits are removed (e.g. a line was deleted), however the rebase
           will still proceed. If set to "error", it will print the previous
           warning and stop the rebase, _g_i_t _r_e_b_a_s_e _-_-_e_d_i_t_-_t_o_d_o can then be
           used to correct the error. If set to "ignore", no checking is done.
           To drop a commit without warning or error, use the ddrroopp command in
           the todo-list. Defaults to "ignore".

       rebase.instructionFormat
           A format string, as specified in ggiitt--lloogg(1), to be used for the
           instruction list during an interactive rebase. The format will
           automatically have the long commit hash prepended to the format.

       receive.advertiseAtomic
           By default, git-receive-pack will advertise the atomic push
           capability to its clients. If you don’t want to advertise this
           capability, set this variable to false.

       receive.advertisePushOptions
           When set to true, git-receive-pack will advertise the push options
           capability to its clients. False by default.

       receive.autogc
           By default, git-receive-pack will run "git-gc --auto" after
           receiving data from git-push and updating refs. You can stop it by
           setting this variable to false.

       receive.certNonceSeed
           By setting this variable to a string, ggiitt rreecceeiivvee--ppaacckk will accept
           a ggiitt ppuusshh ----ssiiggnneedd and verifies it by using a "nonce" protected by
           HMAC using this string as a secret key.

       receive.certNonceSlop
           When a ggiitt ppuusshh ----ssiiggnneedd sent a push certificate with a "nonce"
           that was issued by a receive-pack serving the same repository
           within this many seconds, export the "nonce" found in the
           certificate to GGIITT__PPUUSSHH__CCEERRTT__NNOONNCCEE to the hooks (instead of what
           the receive-pack asked the sending side to include). This may allow
           writing checks in pprree--rreecceeiivvee and ppoosstt--rreecceeiivvee a bit easier.
           Instead of checking GGIITT__PPUUSSHH__CCEERRTT__NNOONNCCEE__SSLLOOPP environment variable
           that records by how many seconds the nonce is stale to decide if
           they want to accept the certificate, they only can check
           GGIITT__PPUUSSHH__CCEERRTT__NNOONNCCEE__SSTTAATTUUSS is OOKK.

       receive.fsckObjects
           If it is set to true, git-receive-pack will check all received
           objects. It will abort in the case of a malformed object or a
           broken link. The result of an abort are only dangling objects.
           Defaults to false. If not set, the value of ttrraannssffeerr..ffsscckkOObbjjeeccttss is
           used instead.

       receive.fsck.<msg-id>
           When rreecceeiivvee..ffsscckkOObbjjeeccttss is set to true, errors can be switched to
           warnings and vice versa by configuring the rreecceeiivvee..ffsscckk..<<mmssgg--iidd>>
           setting where the <<mmssgg--iidd>> is the fsck message ID and the value is
           one of eerrrroorr, wwaarrnn or iiggnnoorree. For convenience, fsck prefixes the
           error/warning with the message ID, e.g. "missingEmail: invalid
           author/committer line - missing email" means that setting
           rreecceeiivvee..ffsscckk..mmiissssiinnggEEmmaaiill == iiggnnoorree will hide that issue.

           This feature is intended to support working with legacy
           repositories which would not pass pushing when rreecceeiivvee..ffsscckkOObbjjeeccttss
           == ttrruuee, allowing the host to accept repositories with certain known
           issues but still catch other issues.

       receive.fsck.skipList
           The path to a sorted list of object names (i.e. one SHA-1 per line)
           that are known to be broken in a non-fatal way and should be
           ignored. This feature is useful when an established project should
           be accepted despite early commits containing errors that can be
           safely ignored such as invalid committer email addresses. Note:
           corrupt objects cannot be skipped with this setting.

       receive.keepAlive
           After receiving the pack from the client, rreecceeiivvee--ppaacckk may produce
           no output (if ----qquuiieett was specified) while processing the pack,
           causing some networks to drop the TCP connection. With this option
           set, if rreecceeiivvee--ppaacckk does not transmit any data in this phase for
           rreecceeiivvee..kkeeeeppAAlliivvee seconds, it will send a short keepalive packet.
           The default is 5 seconds; set to 0 to disable keepalives entirely.

       receive.unpackLimit
           If the number of objects received in a push is below this limit
           then the objects will be unpacked into loose object files. However
           if the number of received objects equals or exceeds this limit then
           the received pack will be stored as a pack, after adding any
           missing delta bases. Storing the pack from a push can make the push
           operation complete faster, especially on slow filesystems. If not
           set, the value of ttrraannssffeerr..uunnppaacckkLLiimmiitt is used instead.

       receive.maxInputSize
           If the size of the incoming pack stream is larger than this limit,
           then git-receive-pack will error out, instead of accepting the pack
           file. If not set or set to 0, then the size is unlimited.

       receive.denyDeletes
           If set to true, git-receive-pack will deny a ref update that
           deletes the ref. Use this to prevent such a ref deletion via a
           push.

       receive.denyDeleteCurrent
           If set to true, git-receive-pack will deny a ref update that
           deletes the currently checked out branch of a non-bare repository.

       receive.denyCurrentBranch
           If set to true or "refuse", git-receive-pack will deny a ref update
           to the currently checked out branch of a non-bare repository. Such
           a push is potentially dangerous because it brings the HEAD out of
           sync with the index and working tree. If set to "warn", print a
           warning of such a push to stderr, but allow the push to proceed. If
           set to false or "ignore", allow such pushes with no message.
           Defaults to "refuse".

           Another option is "updateInstead" which will update the working
           tree if pushing into the current branch. This option is intended
           for synchronizing working directories when one side is not easily
           accessible via interactive ssh (e.g. a live web site, hence the
           requirement that the working directory be clean). This mode also
           comes in handy when developing inside a VM to test and fix code on
           different Operating Systems.

           By default, "updateInstead" will refuse the push if the working
           tree or the index have any difference from the HEAD, but the
           ppuusshh--ttoo--cchheecckkoouutt hook can be used to customize this. See
           ggiitthhooookkss(5).

       receive.denyNonFastForwards
           If set to true, git-receive-pack will deny a ref update which is
           not a fast-forward. Use this to prevent such an update via a push,
           even if that push is forced. This configuration variable is set
           when initializing a shared repository.

       receive.hideRefs
           This variable is the same as ttrraannssffeerr..hhiiddeeRReeffss, but applies only to
           rreecceeiivvee--ppaacckk (and so affects pushes, but not fetches). An attempt
           to update or delete a hidden ref by ggiitt ppuusshh is rejected.

       receive.updateServerInfo
           If set to true, git-receive-pack will run git-update-server-info
           after receiving data from git-push and updating refs.

       receive.shallowUpdate
           If set to true, .git/shallow can be updated when new refs require
           new shallow roots. Otherwise those refs are rejected.

       remote.pushDefault
           The remote to push to by default. Overrides bbrraanncchh..<<nnaammee>>..rreemmoottee
           for all branches, and is overridden by bbrraanncchh..<<nnaammee>>..ppuusshhRReemmoottee for
           specific branches.

       remote.<name>.url
           The URL of a remote repository. See ggiitt--ffeettcchh(1) or ggiitt--ppuusshh(1).

       remote.<name>.pushurl
           The push URL of a remote repository. See ggiitt--ppuusshh(1).

       remote.<name>.proxy
           For remotes that require curl (http, https and ftp), the URL to the
           proxy to use for that remote. Set to the empty string to disable
           proxying for that remote.

       remote.<name>.proxyAuthMethod
           For remotes that require curl (http, https and ftp), the method to
           use for authenticating against the proxy in use (probably set in
           rreemmoottee..<<nnaammee>>..pprrooxxyy). See hhttttpp..pprrooxxyyAAuutthhMMeetthhoodd.

       remote.<name>.fetch
           The default set of "refspec" for ggiitt--ffeettcchh(1). See ggiitt--ffeettcchh(1).

       remote.<name>.push
           The default set of "refspec" for ggiitt--ppuusshh(1). See ggiitt--ppuusshh(1).

       remote.<name>.mirror
           If true, pushing to this remote will automatically behave as if the
           ----mmiirrrroorr option was given on the command line.

       remote.<name>.skipDefaultUpdate
           If true, this remote will be skipped by default when updating using
           ggiitt--ffeettcchh(1) or the uuppddaattee subcommand of ggiitt--rreemmoottee(1).

       remote.<name>.skipFetchAll
           If true, this remote will be skipped by default when updating using
           ggiitt--ffeettcchh(1) or the uuppddaattee subcommand of ggiitt--rreemmoottee(1).

       remote.<name>.receivepack
           The default program to execute on the remote side when pushing. See
           option --receive-pack of ggiitt--ppuusshh(1).

       remote.<name>.uploadpack
           The default program to execute on the remote side when fetching.
           See option --upload-pack of ggiitt--ffeettcchh--ppaacckk(1).

       remote.<name>.tagOpt
           Setting this value to --no-tags disables automatic tag following
           when fetching from remote <name>. Setting it to --tags will fetch
           every tag from remote <name>, even if they are not reachable from
           remote branch heads. Passing these flags directly to ggiitt--ffeettcchh(1)
           can override this setting. See options --tags and --no-tags of ggiitt--
           ffeettcchh(1).

       remote.<name>.vcs
           Setting this to a value <vcs> will cause Git to interact with the
           remote with the git-remote-<vcs> helper.

       remote.<name>.prune
           When set to true, fetching from this remote by default will also
           remove any remote-tracking references that no longer exist on the
           remote (as if the ----pprruunnee option was given on the command line).
           Overrides ffeettcchh..pprruunnee settings, if any.

       remotes.<group>
           The list of remotes which are fetched by "git remote update
           <group>". See ggiitt--rreemmoottee(1).

       repack.useDeltaBaseOffset
           By default, ggiitt--rreeppaacckk(1) creates packs that use delta-base offset.
           If you need to share your repository with Git older than version
           1.4.4, either directly or via a dumb protocol such as http, then
           you need to set this option to "false" and repack. Access from old
           Git versions over the native protocol are unaffected by this
           option.

       repack.packKeptObjects
           If set to true, makes ggiitt rreeppaacckk act as if ----ppaacckk--kkeepptt--oobbjjeeccttss was
           passed. See ggiitt--rreeppaacckk(1) for details. Defaults to ffaallssee normally,
           but ttrruuee if a bitmap index is being written (either via
           ----wwrriittee--bbiittmmaapp--iinnddeexx or rreeppaacckk..wwrriitteeBBiittmmaappss).

       repack.writeBitmaps
           When true, git will write a bitmap index when packing all objects
           to disk (e.g., when ggiitt rreeppaacckk --aa is run). This index can speed up
           the "counting objects" phase of subsequent packs created for clones
           and fetches, at the cost of some disk space and extra time spent on
           the initial repack. This has no effect if multiple packfiles are
           created. Defaults to false.

       rerere.autoUpdate
           When set to true, ggiitt--rreerreerree updates the index with the resulting
           contents after it cleanly resolves conflicts using previously
           recorded resolution. Defaults to false.

       rerere.enabled
           Activate recording of resolved conflicts, so that identical
           conflict hunks can be resolved automatically, should they be
           encountered again. By default, ggiitt--rreerreerree(1) is enabled if there is
           an rrrr--ccaacchhee directory under the $$GGIITT__DDIIRR, e.g. if "rerere" was
           previously used in the repository.

       sendemail.identity
           A configuration identity. When given, causes values in the
           _s_e_n_d_e_m_a_i_l_._<_i_d_e_n_t_i_t_y_> subsection to take precedence over values in
           the _s_e_n_d_e_m_a_i_l section. The default identity is the value of
           sseennddeemmaaiill..iiddeennttiittyy.

       sendemail.smtpEncryption
           See ggiitt--sseenndd--eemmaaiill(1) for description. Note that this setting is
           not subject to the _i_d_e_n_t_i_t_y mechanism.

       sendemail.smtpssl (deprecated)
           Deprecated alias for _s_e_n_d_e_m_a_i_l_._s_m_t_p_E_n_c_r_y_p_t_i_o_n _= _s_s_l.

       sendemail.smtpsslcertpath
           Path to ca-certificates (either a directory or a single file). Set
           it to an empty string to disable certificate verification.

       sendemail.<identity>.*
           Identity-specific versions of the _s_e_n_d_e_m_a_i_l_._*  parameters found
           below, taking precedence over those when the this identity is
           selected, through command-line or sseennddeemmaaiill..iiddeennttiittyy.

       sendemail.aliasesFile, sendemail.aliasFileType, sendemail.annotate,
       sendemail.bcc, sendemail.cc, sendemail.ccCmd, sendemail.chainReplyTo,
       sendemail.confirm, sendemail.envelopeSender, sendemail.from,
       sendemail.multiEdit, sendemail.signedoffbycc, sendemail.smtpPass,
       sendemail.suppresscc, sendemail.suppressFrom, sendemail.to,
       sendemail.smtpDomain, sendemail.smtpServer, sendemail.smtpServerPort,
       sendemail.smtpServerOption, sendemail.smtpUser, sendemail.thread,
       sendemail.transferEncoding, sendemail.validate, sendemail.xmailer
           See ggiitt--sseenndd--eemmaaiill(1) for description.

       sendemail.signedoffcc (deprecated)
           Deprecated alias for sseennddeemmaaiill..ssiiggnneeddooffffbbyycccc.

       showbranch.default
           The default set of branches for ggiitt--sshhooww--bbrraanncchh(1). See ggiitt--sshhooww--
           bbrraanncchh(1).

       splitIndex.maxPercentChange
           When the split index feature is used, this specifies the percent of
           entries the split index can contain compared to the total number of
           entries in both the split index and the shared index before a new
           shared index is written. The value should be between 0 and 100. If
           the value is 0 then a new shared index is always written, if it is
           100 a new shared index is never written. By default the value is
           20, so a new shared index is written if the number of entries in
           the split index would be greater than 20 percent of the total
           number of entries. See ggiitt--uuppddaattee--iinnddeexx(1).

       splitIndex.sharedIndexExpire
           When the split index feature is used, shared index files that were
           not modified since the time this variable specifies will be removed
           when a new shared index file is created. The value "now" expires
           all entries immediately, and "never" suppresses expiration
           altogether. The default value is "2.weeks.ago". Note that a shared
           index file is considered modified (for the purpose of expiration)
           each time a new split-index file is either created based on it or
           read from it. See ggiitt--uuppddaattee--iinnddeexx(1).

       status.relativePaths
           By default, ggiitt--ssttaattuuss(1) shows paths relative to the current
           directory. Setting this variable to ffaallssee shows paths relative to
           the repository root (this was the default for Git prior to v1.5.4).

       status.short
           Set to true to enable --short by default in ggiitt--ssttaattuuss(1). The
           option --no-short takes precedence over this variable.

       status.branch
           Set to true to enable --branch by default in ggiitt--ssttaattuuss(1). The
           option --no-branch takes precedence over this variable.

       status.displayCommentPrefix
           If set to true, ggiitt--ssttaattuuss(1) will insert a comment prefix before
           each output line (starting with ccoorree..ccoommmmeennttCChhaarr, i.e.  ## by
           default). This was the behavior of ggiitt--ssttaattuuss(1) in Git 1.8.4 and
           previous. Defaults to false.

       status.showUntrackedFiles
           By default, ggiitt--ssttaattuuss(1) and ggiitt--ccoommmmiitt(1) show files which are
           not currently tracked by Git. Directories which contain only
           untracked files, are shown with the directory name only. Showing
           untracked files means that Git needs to lstat() all the files in
           the whole repository, which might be slow on some systems. So, this
           variable controls how the commands displays the untracked files.
           Possible values are:

           ·   nnoo - Show no untracked files.

           ·   nnoorrmmaall - Show untracked files and directories.

           ·   aallll - Show also individual files in untracked directories.

           If this variable is not specified, it defaults to _n_o_r_m_a_l. This
           variable can be overridden with the -u|--untracked-files option of
           ggiitt--ssttaattuuss(1) and ggiitt--ccoommmmiitt(1).

       status.submoduleSummary
           Defaults to false. If this is set to a non zero number or true
           (identical to -1 or an unlimited number), the submodule summary
           will be enabled and a summary of commits for modified submodules
           will be shown (see --summary-limit option of ggiitt--ssuubbmmoodduullee(1)).
           Please note that the summary output command will be suppressed for
           all submodules when ddiiffff..iiggnnoorreeSSuubbmmoodduulleess is set to _a_l_l or only for
           those submodules where ssuubbmmoodduullee..<<nnaammee>>..iiggnnoorree==aallll. The only
           exception to that rule is that status and commit will show staged
           submodule changes. To also view the summary for ignored submodules
           you can either use the --ignore-submodules=dirty command-line
           option or the _g_i_t _s_u_b_m_o_d_u_l_e _s_u_m_m_a_r_y command, which shows a similar
           output but does not honor these settings.

       stash.showPatch
           If this is set to true, the ggiitt ssttaasshh sshhooww command without an
           option will show the stash in patch form. Defaults to false. See
           description of _s_h_o_w command in ggiitt--ssttaasshh(1).

       stash.showStat
           If this is set to true, the ggiitt ssttaasshh sshhooww command without an
           option will show diffstat of the stash. Defaults to true. See
           description of _s_h_o_w command in ggiitt--ssttaasshh(1).

       submodule.<name>.url
           The URL for a submodule. This variable is copied from the
           .gitmodules file to the git config via _g_i_t _s_u_b_m_o_d_u_l_e _i_n_i_t. The user
           can change the configured URL before obtaining the submodule via
           _g_i_t _s_u_b_m_o_d_u_l_e _u_p_d_a_t_e. If neither submodule.<name>.active or
           submodule.active are set, the presence of this variable is used as
           a fallback to indicate whether the submodule is of interest to git
           commands. See ggiitt--ssuubbmmoodduullee(1) and ggiittmmoodduulleess(5) for details.

       submodule.<name>.update
           The default update procedure for a submodule. This variable is
           populated by ggiitt ssuubbmmoodduullee iinniitt from the ggiittmmoodduulleess(5) file. See
           description of _u_p_d_a_t_e command in ggiitt--ssuubbmmoodduullee(1).

       submodule.<name>.branch
           The remote branch name for a submodule, used by ggiitt ssuubbmmoodduullee
           uuppddaattee ----rreemmoottee. Set this option to override the value found in the
           ..ggiittmmoodduulleess file. See ggiitt--ssuubbmmoodduullee(1) and ggiittmmoodduulleess(5) for
           details.

       submodule.<name>.fetchRecurseSubmodules
           This option can be used to control recursive fetching of this
           submodule. It can be overridden by using the
           --[no-]recurse-submodules command-line option to "git fetch" and
           "git pull". This setting will override that from in the
           ggiittmmoodduulleess(5) file.

       submodule.<name>.ignore
           Defines under what circumstances "git status" and the diff family
           show a submodule as modified. When set to "all", it will never be
           considered modified (but it will nonetheless show up in the output
           of status and commit when it has been staged), "dirty" will ignore
           all changes to the submodules work tree and takes only differences
           between the HEAD of the submodule and the commit recorded in the
           superproject into account. "untracked" will additionally let
           submodules with modified tracked files in their work tree show up.
           Using "none" (the default when this option is not set) also shows
           submodules that have untracked files in their work tree as changed.
           This setting overrides any setting made in .gitmodules for this
           submodule, both settings can be overridden on the command line by
           using the "--ignore-submodules" option. The _g_i_t _s_u_b_m_o_d_u_l_e commands
           are not affected by this setting.

       submodule.<name>.active
           Boolean value indicating if the submodule is of interest to git
           commands. This config option takes precedence over the
           submodule.active config option.

       submodule.active
           A repeated field which contains a pathspec used to match against a
           submodule’s path to determine if the submodule is of interest to
           git commands.

       submodule.fetchJobs
           Specifies how many submodules are fetched/cloned at the same time.
           A positive integer allows up to that number of submodules fetched
           in parallel. A value of 0 will give some reasonable default. If
           unset, it defaults to 1.

       submodule.alternateLocation
           Specifies how the submodules obtain alternates when submodules are
           cloned. Possible values are nnoo, ssuuppeerrpprroojjeecctt. By default nnoo is
           assumed, which doesn’t add references. When the value is set to
           ssuuppeerrpprroojjeecctt the submodule to be cloned computes its alternates
           location relative to the superprojects alternate.

       submodule.alternateErrorStrategy
           Specifies how to treat errors with the alternates for a submodule
           as computed via ssuubbmmoodduullee..aalltteerrnnaatteeLLooccaattiioonn. Possible values are
           iiggnnoorree, iinnffoo, ddiiee. Default is ddiiee.

       tag.forceSignAnnotated
           A boolean to specify whether annotated tags created should be GPG
           signed. If ----aannnnoottaattee is specified on the command line, it takes
           precedence over this option.

       tag.sort
           This variable controls the sort ordering of tags when displayed by
           ggiitt--ttaagg(1). Without the "--sort=<value>" option provided, the value
           of this variable will be used as the default.

       tar.umask
           This variable can be used to restrict the permission bits of tar
           archive entries. The default is 0002, which turns off the world
           write bit. The special value "user" indicates that the archiving
           user’s umask will be used instead. See umask(2) and ggiitt--aarrcchhiivvee(1).

       transfer.fsckObjects
           When ffeettcchh..ffsscckkOObbjjeeccttss or rreecceeiivvee..ffsscckkOObbjjeeccttss are not set, the
           value of this variable is used instead. Defaults to false.

       transfer.hideRefs
           String(s) rreecceeiivvee--ppaacckk and uuppllooaadd--ppaacckk use to decide which refs to
           omit from their initial advertisements. Use more than one
           definition to specify multiple prefix strings. A ref that is under
           the hierarchies listed in the value of this variable is excluded,
           and is hidden when responding to ggiitt ppuusshh or ggiitt ffeettcchh. See
           rreecceeiivvee..hhiiddeeRReeffss and uuppllooaaddppaacckk..hhiiddeeRReeffss for program-specific
           versions of this config.

           You may also include a !!  in front of the ref name to negate the
           entry, explicitly exposing it, even if an earlier entry marked it
           as hidden. If you have multiple hideRefs values, later entries
           override earlier ones (and entries in more-specific config files
           override less-specific ones).

           If a namespace is in use, the namespace prefix is stripped from
           each reference before it is matched against ttrraannssffeerr..hhiiddeerreeffss
           patterns. For example, if rreeffss//hheeaaddss//mmaasstteerr is specified in
           ttrraannssffeerr..hhiiddeeRReeffss and the current namespace is ffoooo, then
           rreeffss//nnaammeessppaacceess//ffoooo//rreeffss//hheeaaddss//mmaasstteerr is omitted from the
           advertisements but rreeffss//hheeaaddss//mmaasstteerr and
           rreeffss//nnaammeessppaacceess//bbaarr//rreeffss//hheeaaddss//mmaasstteerr are still advertised as
           so-called "have" lines. In order to match refs before stripping,
           add a ^^ in front of the ref name. If you combine !!  and ^^, !!  must
           be specified first.

           Even if you hide refs, a client may still be able to steal the
           target objects via the techniques described in the "SECURITY"
           section of the ggiittnnaammeessppaacceess(7) man page; it’s best to keep private
           data in a separate repository.

       transfer.unpackLimit
           When ffeettcchh..uunnppaacckkLLiimmiitt or rreecceeiivvee..uunnppaacckkLLiimmiitt are not set, the
           value of this variable is used instead. The default value is 100.

       uploadarchive.allowUnreachable
           If true, allow clients to use ggiitt aarrcchhiivvee ----rreemmoottee to request any
           tree, whether reachable from the ref tips or not. See the
           discussion in the "SECURITY" section of ggiitt--uuppllooaadd--aarrcchhiivvee(1) for
           more details. Defaults to ffaallssee.

       uploadpack.hideRefs
           This variable is the same as ttrraannssffeerr..hhiiddeeRReeffss, but applies only to
           uuppllooaadd--ppaacckk (and so affects only fetches, not pushes). An attempt
           to fetch a hidden ref by ggiitt ffeettcchh will fail. See also
           uuppllooaaddppaacckk..aalllloowwTTiippSSHHAA11IInnWWaanntt.

       uploadpack.allowTipSHA1InWant
           When uuppllooaaddppaacckk..hhiiddeeRReeffss is in effect, allow uuppllooaadd--ppaacckk to accept
           a fetch request that asks for an object at the tip of a hidden ref
           (by default, such a request is rejected). See also
           uuppllooaaddppaacckk..hhiiddeeRReeffss. Even if this is false, a client may be able to
           steal objects via the techniques described in the "SECURITY"
           section of the ggiittnnaammeessppaacceess(7) man page; it’s best to keep private
           data in a separate repository.

       uploadpack.allowReachableSHA1InWant
           Allow uuppllooaadd--ppaacckk to accept a fetch request that asks for an object
           that is reachable from any ref tip. However, note that calculating
           object reachability is computationally expensive. Defaults to
           ffaallssee. Even if this is false, a client may be able to steal objects
           via the techniques described in the "SECURITY" section of the
           ggiittnnaammeessppaacceess(7) man page; it’s best to keep private data in a
           separate repository.

       uploadpack.allowAnySHA1InWant
           Allow uuppllooaadd--ppaacckk to accept a fetch request that asks for any
           object at all. Defaults to ffaallssee.

       uploadpack.keepAlive
           When uuppllooaadd--ppaacckk has started ppaacckk--oobbjjeeccttss, there may be a quiet
           period while ppaacckk--oobbjjeeccttss prepares the pack. Normally it would
           output progress information, but if ----qquuiieett was used for the fetch,
           ppaacckk--oobbjjeeccttss will output nothing at all until the pack data begins.
           Some clients and networks may consider the server to be hung and
           give up. Setting this option instructs uuppllooaadd--ppaacckk to send an empty
           keepalive packet every uuppllooaaddppaacckk..kkeeeeppAAlliivvee seconds. Setting this
           option to 0 disables keepalive packets entirely. The default is 5
           seconds.

       uploadpack.packObjectsHook
           If this option is set, when uuppllooaadd--ppaacckk would run ggiitt ppaacckk--oobbjjeeccttss
           to create a packfile for a client, it will run this shell command
           instead. The ppaacckk--oobbjjeeccttss command and arguments it _w_o_u_l_d have run
           (including the ggiitt ppaacckk--oobbjjeeccttss at the beginning) are appended to
           the shell command. The stdin and stdout of the hook are treated as
           if ppaacckk--oobbjjeeccttss itself was run. I.e., uuppllooaadd--ppaacckk will feed input
           intended for ppaacckk--oobbjjeeccttss to the hook, and expects a completed
           packfile on stdout.

           Note that this configuration variable is ignored if it is seen in
           the repository-level config (this is a safety measure against
           fetching from untrusted repositories).

       url.<base>.insteadOf
           Any URL that starts with this value will be rewritten to start,
           instead, with <base>. In cases where some site serves a large
           number of repositories, and serves them with multiple access
           methods, and some users need to use different access methods, this
           feature allows people to specify any of the equivalent URLs and
           have Git automatically rewrite the URL to the best alternative for
           the particular user, even for a never-before-seen repository on the
           site. When more than one insteadOf strings match a given URL, the
           longest match is used.

           Note that any protocol restrictions will be applied to the
           rewritten URL. If the rewrite changes the URL to use a custom
           protocol or remote helper, you may need to adjust the
           pprroottooccooll..**..aallllooww config to permit the request. In particular,
           protocols you expect to use for submodules must be set to aallwwaayyss
           rather than the default of uusseerr. See the description of
           pprroottooccooll..aallllooww above.

       url.<base>.pushInsteadOf
           Any URL that starts with this value will not be pushed to; instead,
           it will be rewritten to start with <base>, and the resulting URL
           will be pushed to. In cases where some site serves a large number
           of repositories, and serves them with multiple access methods, some
           of which do not allow push, this feature allows people to specify a
           pull-only URL and have Git automatically use an appropriate URL to
           push, even for a never-before-seen repository on the site. When
           more than one pushInsteadOf strings match a given URL, the longest
           match is used. If a remote has an explicit pushurl, Git will ignore
           this setting for that remote.

       user.email
           Your email address to be recorded in any newly created commits. Can
           be overridden by the GGIITT__AAUUTTHHOORR__EEMMAAIILL, GGIITT__CCOOMMMMIITTTTEERR__EEMMAAIILL, and
           EEMMAAIILL environment variables. See ggiitt--ccoommmmiitt--ttrreeee(1).

       user.name
           Your full name to be recorded in any newly created commits. Can be
           overridden by the GGIITT__AAUUTTHHOORR__NNAAMMEE and GGIITT__CCOOMMMMIITTTTEERR__NNAAMMEE
           environment variables. See ggiitt--ccoommmmiitt--ttrreeee(1).

       user.useConfigOnly
           Instruct Git to avoid trying to guess defaults for uusseerr..eemmaaiill and
           uusseerr..nnaammee, and instead retrieve the values only from the
           configuration. For example, if you have multiple email addresses
           and would like to use a different one for each repository, then
           with this configuration option set to ttrruuee in the global config
           along with a name, Git will prompt you to set up an email before
           making new commits in a newly cloned repository. Defaults to ffaallssee.

       user.signingKey
           If ggiitt--ttaagg(1) or ggiitt--ccoommmmiitt(1) is not selecting the key you want it
           to automatically when creating a signed tag or commit, you can
           override the default selection with this variable. This option is
           passed unchanged to gpg’s --local-user parameter, so you may
           specify a key using any method that gpg supports.

       versionsort.prereleaseSuffix (deprecated)
           Deprecated alias for vveerrssiioonnssoorrtt..ssuuffffiixx. Ignored if
           vveerrssiioonnssoorrtt..ssuuffffiixx is set.

       versionsort.suffix
           Even when version sort is used in ggiitt--ttaagg(1), tagnames with the
           same base version but different suffixes are still sorted
           lexicographically, resulting e.g. in prerelease tags appearing
           after the main release (e.g. "1.0-rc1" after "1.0"). This variable
           can be specified to determine the sorting order of tags with
           different suffixes.

           By specifying a single suffix in this variable, any tagname
           containing that suffix will appear before the corresponding main
           release. E.g. if the variable is set to "-rc", then all "1.0-rcX"
           tags will appear before "1.0". If specified multiple times, once
           per suffix, then the order of suffixes in the configuration will
           determine the sorting order of tagnames with those suffixes. E.g.
           if "-pre" appears before "-rc" in the configuration, then all
           "1.0-preX" tags will be listed before any "1.0-rcX" tags. The
           placement of the main release tag relative to tags with various
           suffixes can be determined by specifying the empty suffix among
           those other suffixes. E.g. if the suffixes "-rc", "", "-ck" and
           "-bfs" appear in the configuration in this order, then all
           "v4.8-rcX" tags are listed first, followed by "v4.8", then
           "v4.8-ckX" and finally "v4.8-bfsX".

           If more than one suffixes match the same tagname, then that tagname
           will be sorted according to the suffix which starts at the earliest
           position in the tagname. If more than one different matching
           suffixes start at that earliest position, then that tagname will be
           sorted according to the longest of those suffixes. The sorting
           order between different suffixes is undefined if they are in
           multiple config files.

       web.browser
           Specify a web browser that may be used by some commands. Currently
           only ggiitt--iinnssttaawweebb(1) and ggiitt--hheellpp(1) may use it.

GGIITT
       Part of the ggiitt(1) suite

Git 2.13.6                        09/24/2017                     GIT-CONFIG(1)
usage: git [--version] [--help] [-C <path>] [-c name=value]
           [--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]
           [-p | --paginate | --no-pager] [--no-replace-objects] [--bare]
           [--git-dir=<path>] [--work-tree=<path>] [--namespace=<name>]
           <command> [<args>]

These are common Git commands used in various situations:

start a working area (see also: git help tutorial)
   clone      Clone a repository into a new directory
   init       Create an empty Git repository or reinitialize an existing one

work on the current change (see also: git help everyday)
   add        Add file contents to the index
   mv         Move or rename a file, a directory, or a symlink
   reset      Reset current HEAD to the specified state
   rm         Remove files from the working tree and from the index

examine the history and state (see also: git help revisions)
   bisect     Use binary search to find the commit that introduced a bug
   grep       Print lines matching a pattern
   log        Show commit logs
   show       Show various types of objects
   status     Show the working tree status

grow, mark and tweak your common history
   branch     List, create, or delete branches
   checkout   Switch branches or restore working tree files
   commit     Record changes to the repository
   diff       Show changes between commits, commit and working tree, etc
   merge      Join two or more development histories together
   rebase     Reapply commits on top of another base tip
   tag        Create, list, delete or verify a tag object signed with GPG

collaborate (see also: git help workflows)
   fetch      Download objects and refs from another repository
   pull       Fetch from and integrate with another repository or a local branch
   push       Update remote refs along with associated objects

'git help -a' and 'git help -g' list available subcommands and some
concept guides. See 'git help <command>' or 'git help <concept>'
to read about a specific subcommand or concept.

You can get quick help on any git command with git CMD -h, or longer and more general help with help (same as man git-CMD). Just to show you there is extensive documentation available.

git as an object (file) store: blobs

Create a new object based on some data (e.g., file contents)

For now, let's just look at git as a database, or as a kind of key-value store, like S3 perhaps, except one that can never be changed after objects are created.

echo 'Hello World!' > f
git hash-object -t blob -w f
rm f

git-hash-object  - Compute object ID and optionally creates a blob from a file
980a0d5f19a64b4b30a87d4206aade58726b60e3

Unique identifier for this data: each distinct file gets its own hash ("content-addressable storage")

echo -e 'blob 13\0Hello World!' | sha1sum

980a0d5f19a64b4b30a87d4206aade58726b60e3  -

git cat-file -t 980a0d5f19a64b4b30a87d4206aade58726b60e3 # object type
git cat-file -s 980a # any unique prefix of hash         # object size
git cat-file -p 980a0d5                                  # contents
          file1=980a0d5f19a64b4b30a87d4206aade58726b60e3 # save for later

git-cat-file     - Provide content or type and size information for repository objects
blob
13
Hello World!

file2=$( echo 'Something completely different.' \
         | git hash-object -t blob -w --stdin )
echo $file2

1a0985327d433bdfc3ea3c2b0a0443b3545064ac

git cat-file -p $file2

Something completely different.

Where'd the data go?

find .git/objects -type f

.git/objects/98/0a0d5f19a64b4b30a87d4206aade58726b60e3
.git/objects/1a/0985327d433bdfc3ea3c2b0a0443b3545064ac

Collecting objects: trees (directories)

( echo -e 100644 blob $file1\\t"hello.txt" \
; echo -e 100644 blob $file2\\t"other.txt" \
) | git mktree

git-mktree       - Build a tree-object from ls-tree formatted text
011ed906a8c5b0c0c14c0cad0a69d3969251b71f

A directory with two files, references to their contents by hash

tree0=011ed906a8c5b0c0c14c0cad0a69d3969251b71f
git cat-file -t $tree0
git cat-file -p $tree0

tree
100644 blob 980a0d5f19a64b4b30a87d4206aade58726b60e3	hello.txt
100644 blob 1a0985327d433bdfc3ea3c2b0a0443b3545064ac	other.txt

This is again just a hash of the tree contents, so every unique directory gets a unique hash, and since these contents include the unique identifiers of the files as well, this extends to the file contents.

( echo -e 040000 tree $tree0\\t"stuff" \
; echo -e 100644 blob $file1\\t"README" \
) | git mktree

c3595f6745f977f2450eeeb5bd94ccd2e4fba498

Another directory, containing the first directory, nested

tree1=c3595f6745f977f2450eeeb5bd94ccd2e4fba498
git cat-file -p $tree1

100644 blob 980a0d5f19a64b4b30a87d4206aade58726b60e3	README
040000 tree 011ed906a8c5b0c0c14c0cad0a69d3969251b71f	stuff

Notice also that it sorted the directory by filename in order to normalize the contents.

git ls-tree -tr $tree1

git-ls-tree      - List the contents of a tree object
100644 blob 980a0d5f19a64b4b30a87d4206aade58726b60e3	README
040000 tree 011ed906a8c5b0c0c14c0cad0a69d3969251b71f	stuff
100644 blob 980a0d5f19a64b4b30a87d4206aade58726b60e3	stuff/hello.txt
100644 blob 1a0985327d433bdfc3ea3c2b0a0443b3545064ac	stuff/other.txt

Since the contents of this tree include the unique identifier for another tree, it becomes the unique identifier for this entire directory tree and all its contents.

A tree is "snapshot" of a directory

Just as a blob is a snapshot of a file

file3=$( echo 'New and improved.' \
         | git hash-object -t blob -w --stdin )
tree2=$( ( echo -e 100644 blob $file3\\t"README" \
         ; echo -e 040000 tree $tree0\\t"stuff" \
         ) | git mktree )
echo $tree2
git ls-tree -tr $tree2

674e727fabfeb840b5c4e36f2c33610dfb50458e
100644 blob f25e220dd7c5d3082f9754786f7fd6fcae6db473	README
040000 tree 011ed906a8c5b0c0c14c0cad0a69d3969251b71f	stuff
100644 blob 980a0d5f19a64b4b30a87d4206aade58726b60e3	stuff/hello.txt
100644 blob 1a0985327d433bdfc3ea3c2b0a0443b3545064ac	stuff/other.txt

The contents changed, so we get a new hash, but only the hash of the README file changed, the rest is the same.

Comparing trees

Comparing snapshots is what git's for

git diff-tree -p $tree1 $tree2

git-diff-tree    - Compares the content and mode of blobs found via two tree objects
diff --git a/README b/README
index 980a0d5..f25e220 100644
--- a/README
+++ b/README
@@ -1 +1 @@
-Hello World!
+New and improved.

Comparing trees is very efficient if there are only a small number of changes (why?).

We can now represent the full state of a directory (e.g., the repository), and could think of the repository as a kind of multi-zip file, where we can store lots of stuff and each hash lets us get a new directory. We could use this to record the tree hash each time we make a change. What we need next is a way of keeping track of all these trees and their relationships to each other (e.g., over time).

Extracting trees

git archive $tree2 | tar tvf -

git-archive      - Create an archive of files from a named tree
-rw-rw-r-- root/root        18 2017-10-17 11:02 README
drwxrwxr-x root/root         0 2017-10-17 11:02 stuff/
-rw-rw-r-- root/root        13 2017-10-17 11:02 stuff/hello.txt
-rw-rw-r-- root/root        32 2017-10-17 11:02 stuff/other.txt

Just to prove that the data is all there, we can ask git to convert a tree to a tar or zip file.

Versioning: commit (revision)

A commit is a tree and some metadata

commit1=$( git commit-tree -m "Add some text files to my tree" $tree1 )
echo $commit1

git-commit-tree  - Create a new commit object
2efdb20ab8b7d2e585ae0cd4209f9c4c525d94e1

git cat-file -p $commit1

tree c3595f6745f977f2450eeeb5bd94ccd2e4fba498
author Dylan Simon <dylan@dylex.net> 1497996000 -0400
committer Dylan Simon <dylan@dylex.net> 1497996000 -0400

Add some text files to my tree

A commit contains:

• Tree hash
• Author name, email, timestamp
• Committer name, email, timestamp (if someone else re-commits changes with annotations)
• Commit message: arbitrary text (with -m or in editor)

git config --get 'user.name' # ~/.gitconfig

Dylan Simon

• Parent commit(s), pointing to previous revision(s)

A commit is just an object like trees or blobs, and its hash is the unique identifier for its contents: the tree and metadata.

commit2=$( git commit-tree -p $commit1 -m "Improve README with new stuff" $tree2 )
echo $commit2

0b5bcf36d47bf5abc4ec35c72e9a2c0294d8d832

git cat-file -p $commit2

tree 674e727fabfeb840b5c4e36f2c33610dfb50458e
parent 2efdb20ab8b7d2e585ae0cd4209f9c4c525d94e1
author Dylan Simon <dylan@dylex.net> 1498158000 -0400
committer Dylan Simon <dylan@dylex.net> 1498158000 -0400

Improve README with new stuff

By walking back through the chain of parents to the root, you can see the previous states (history) of the repository

Commits do not represent "diffs": they represent a snapshot state of the files

But git can easily construct these diffs

Commits can have multiple parents, in the case of merges (but usually only 2)

Commit objects form a DAG (directed, acyclic graph)

Why acyclic?

Graph arrows point backwards in time

Examining commit objects

Reference objects indirectly

• COMMIT^: commit's (first) parent
• COMMIT~N: Nth ancestor
• COMMIT^{/TEXT}: most recent ancestor with TEXT in commit message
• COMMIT:PATH: tree or blob object for PATH within COMMIT

git show "$commit2^{/text files}:stuff/hello.txt"

git-show         - Show various types of objects
Hello World!

git log --graph $commit2

git-log          - Show commit logs
* commit 0b5bcf36d47bf5abc4ec35c72e9a2c0294d8d832
| Author: Dylan Simon <dylan@dylex.net>
| Date:   Thu Jun 22 15:00:00 2017
| 
|     Improve README with new stuff
| 
* commit 2efdb20ab8b7d2e585ae0cd4209f9c4c525d94e1
  Author: Dylan Simon <dylan@dylex.net>
  Date:   Tue Jun 20 18:00:00 2017
  
      Add some text files to my tree

`git log [START..]END`

start with END and display all parents (stopping before START; strictly, ancestors of END but not START)

`git log REV1...REV2`

all ancestors of REV1 xor REV2

`git log -- PATH ...`

only commits with changes under `PATH`

`git log -p`

include diffs for each commit (can add other `diff` options, too)

`git log --graph`

include the commit graph

Many more to filter/search/reformat commit display

gitk (or github)

git diff $commit1 $commit2

git-diff         - Show changes between commits, commit and working tree, etc
diff --git a/README b/README
index 980a0d5..f25e220 100644
--- a/README
+++ b/README
@@ -1 +1 @@
-Hello World!
+New and improved.

`git diff COMMIT1 COMMIT2 [-- PATH ...]`

show changes between two commits, restricted to changes under `PATH`

`git diff --stat`

summarize changes, one line per file (useful with `log`)

`git diff --word-diff`

show edits to individual words instead of lines

Many other standard diff options (-a, -b, -U5, ...)

What about renames?

Git doesn't know anything about renames... but it can guess

`git diff -M[p]`

detect renames (as files at least *p*0% similar)

`git diff -C[p]`

detect copies as well

Commits by name: refs (branches...)

Finally, something that can change

Commits are static, immutable objects, so we need some way to represent the changing state of a repository.

git update-ref refs/heads/master $commit1
git show-ref

git-update-ref   - Update the object name stored in a ref safely
git-show-ref     - List references in a local repository
2efdb20ab8b7d2e585ae0cd4209f9c4c525d94e1 refs/heads/master

git update-ref refs/heads/master $commit2
cat .git/refs/heads/master

0b5bcf36d47bf5abc4ec35c72e9a2c0294d8d832

By convention (and because all the higher-level git commands expect it), branch names start with refs/heads/ (which can thus be omitted), but can be any valid file name after that, like dylan/refactor or release/2.x.

git show master

commit 0b5bcf36d47bf5abc4ec35c72e9a2c0294d8d832 (HEAD -> master)
Author: Dylan Simon <dylan@dylex.net>
Date:   Thu Jun 22 15:00:00 2017

    Improve README with new stuff

diff --git a/README b/README
index 980a0d5..f25e220 100644
--- a/README
+++ b/README
@@ -1 +1 @@
-Hello World!
+New and improved.

git update-ref refs/heads/dylan/refactor master
git show-ref

0b5bcf36d47bf5abc4ec35c72e9a2c0294d8d832 refs/heads/dylan/refactor
0b5bcf36d47bf5abc4ec35c72e9a2c0294d8d832 refs/heads/master

... And tags

References can also represent tags, under refs/tags/ by convention. Unlike branch references, you usually don't move tags after they're created.

git tag -m "Presented at SciCon 2017-06-27" scicon17 master
git show-ref

git-tag          - Create, list, delete or verify a tag object signed with GPG
0b5bcf36d47bf5abc4ec35c72e9a2c0294d8d832 refs/heads/dylan/refactor
0b5bcf36d47bf5abc4ec35c72e9a2c0294d8d832 refs/heads/master
aa6742b68e7ea09070071d514e2030683f4ffd57 refs/tags/scicon17

Tags are also a type of object, the last kind we'll see, containing just a name, annotation (message), and commit hash. Notice that refering references, like commits, is flexible, so you can leave off refs/ and another part (tags/, heads/, or remotes/).

git cat-file -p tags/scicon17

object 0b5bcf36d47bf5abc4ec35c72e9a2c0294d8d832
type commit
tag scicon17
tagger Dylan Simon <dylan@dylex.net> 1498575600 -0400

Presented at SciCon 2017-06-27

Revision: any way to refer to a commit object (branch, tag, hash, ^, ...)

Isn't this wasteful?

echo $commit2 | git pack-objects --revs pack
ls -l pack-*

git-pack-objects - Create a packed archive of objects
Counting objects: 8, done.
Delta compression using up to 24 threads.
Compressing objects: 100% (5/5), done.
9c5a911abad74b62a7fefb630c71f6b30859a9dc
Writing objects: 100% (8/8), done.
Total 8 (delta 0), reused 0 (delta 0)
-r--r--r-- 1 dylan dylan 1296 Oct 17 11:02 pack-9c5a911abad74b62a7fefb630c71f6b30859a9dc.idx
-r--r--r-- 1 dylan dylan  661 Oct 17 11:02 pack-9c5a911abad74b62a7fefb630c71f6b30859a9dc.pack

These packs are compressed, and yes this uses delta compression, meaning it is storing things like diffs. However, it's important to remember that these diffs don't necessarily have anything to do with your commits, but are just based on efficient compression and file similarity.

Linux kernel:

• raw source: 700MB
• commits: 600k (since 2005)

• git repo: 1.3GB

  "Don't worry about it."

Caveat

git is designed for text files

Can handle any file in theory (github limit: 100MB), but poor for binary files

If you start putting GB-size binary data files in your git repo, you'll probably be unhappy. Things can get a little slow, but mainly remember that git will keep a copy of the object, doubling your disk usage.

Best practice is not to store generated content in git (and to add such files to .gitignore instead).

Part 2: Local Workflows

Convenient commit construction

You now know pretty much everything about how git actually works -- enough to be dangerous but not particularly useful. These commands can be rather impractical, so the rest is just higher-level ways of interacting with git more efficiently.

Between filesystem and trees: index ("cache")

Moving files between git and your local working tree (disk)

The index, stored in .git/index as a mini object-store for a single tree (or a few), is a staging location between the files on disk and the main git object store. Sometimes referred to as "cache" (in the more traditional sense of the word: a place to keep things, rather than the computer memory sense).

git read-tree $tree1
file .git/index
git ls-files

git-read-tree    - Reads tree information into the index
.git/index: Git index, version 2, 3 entries
git-ls-files     - Show information about files in the index and the working tree
README
stuff/hello.txt
stuff/other.txt

This copies an existing tree object into the index, whence we can get it to your working directory.

git checkout-index -a
ls -R

git-checkout-index - Copy files from the index to the working tree
.:
README  stuff

./stuff:
hello.txt  other.txt

Working with the index is one of the most important parts of day-to-day git.

From files to index: staging

Staging changes to the index, from local changes made on disk

echo 'New and improved.' > README
git diff

diff --git a/README b/README
index 980a0d5..f25e220 100644
--- a/README
+++ b/README
@@ -1 +1 @@
-Hello World!
+New and improved.

git add README

git-add          - Add file contents to the index

add just updates the index to match whatever's on disk, for the files you give it.

git write-tree
echo $tree2

git-write-tree   - Create a tree object from the current index
674e727fabfeb840b5c4e36f2c33610dfb50458e
674e727fabfeb840b5c4e36f2c33610dfb50458e

Notice this is the same tree as the one we created earlier, because it has the same contents.

git rm stuff/other.txt
git ls-files

git-rm           - Remove files from the working tree and from the index
rm 'stuff/other.txt'
README
stuff/hello.txt

git mv README README.md
ls

git-mv           - Move or rename a file, a directory, or a symlink
README.md  stuff

quick reference: updating the index

`git add -u [FILE|DIR] ...`

update *existing* index files from disk (update+remove entries)

`git add FILE|DIR ...`

update index files from disk (update+add entries)

`git add -A [FILE|DIR] ...`

update index to match disk (update+add+remove entries)

`git add -p ...`

*interactively* ask what to "stage" to index

`git mv SRC DST`

rename file/dir on disk and in index

git rm [-r] [-f] FILE|DIR

remove file (dir) from disk and index (even if local changes!)

`git rm --cached ...`

remove from index only (but not disk)

From index to files

Checking out the index to overwrite local changes

We saw above that checkout-index can copy files from the index to the disk, but there are also simpler options.

echo 'maybe not...' >> README.md
git diff

diff --git a/README.md b/README.md
index f25e220..63a9b90 100644
--- a/README.md
+++ b/README.md
@@ -1 +1,2 @@
 New and improved.
+maybe not...

git checkout -- README.md
git diff

git-checkout     - Switch branches or restore working tree files

quick reference: discarding changes

`git checkout -- FILE|DIR ...`

overwrite files on disk from index

`git checkout -p`

interactively ask what to "discard" from disk

checkout does other things before the --

Your current branch: HEAD

git symbolic-ref HEAD # show HEAD ref
cat .git/HEAD

git-symbolic-ref - Read, modify and delete symbolic refs
refs/heads/master
ref: refs/heads/master

A symbolic ref is a reference to another ref, kind of like a symbolic link or "pointer pointer". HEAD is a pointer to the current branch (name).

git checkout dylan/refactor # also shows brief status of local 
git symbolic-ref HEAD
git branch

D	README
A	README.md
D	stuff/other.txt
Switched to branch 'dylan/refactor'
refs/heads/dylan/refactor
git-branch       - List, create, or delete branches
* dylan/refactor
  master

quick reference: branches

`git checkout REV`

switch to a branch or "detached" revision (change HEAD)

git branch NEWBRANCH [REV]

git checkout -b NEWBRANCH [REV]

create (and switch to) new branch at REV (`HEAD`)

`git checkout -m`

switch to branch and bring along un-committed changes on disk

`git checkout REV -- PATH ...`

overwrite files on disk from revision (but don't switch branches)

`git branch -va`

list all branches and latest commit

`git branch -m OLDBRANCH NEWBRANCH`

`git branch -d OLDBRANCH`

rename or delete branch

From index to HEAD: committing

Adding commits to your current branch from the index

git commit -m "Mark down 'README'; no more other.txt"

git-commit       - Record changes to the repository
[dylan/refactor e4212ad] Mark down 'README'; no more other.txt
 2 files changed, 1 deletion(-)
 rename README => README.md (100%)
 delete mode 100644 stuff/other.txt

git branch -va

* dylan/refactor e4212ad Mark down 'README'; no more other.txt
  master         0b5bcf3 Improve README with new stuff

git log --stat -2

commit e4212ad336cbaf2c4a5b454af07a484b1b09b83b (HEAD -> dylan/refactor)
Author: Dylan Simon <dylan@dylex.net>
Date:   Fri Jun 30 13:00:00 2017

    Mark down 'README'; no more other.txt

 README => README.md | 0
 stuff/other.txt     | 1 -
 2 files changed, 1 deletion(-)

commit 0b5bcf36d47bf5abc4ec35c72e9a2c0294d8d832 (tag: scicon17, master)
Author: Dylan Simon <dylan@dylex.net>
Date:   Thu Jun 22 15:00:00 2017

    Improve README with new stuff

 README | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

quick reference: commit

`git commit -a`

do `git add -u` and then commit (also `-p`)

git commit -m MSG1 [-m MSG2 ...]

(multi-paragraph) commit message (instead of invoking editor)

`git commit -v`

invoke editor and show full diff to write commit message

`git commit -- PATH...`

commit all changes to files on disk (bypass index)

commit message guidelines

• Use present tense in brief summary: "Fix crash with large N", "Cleanup temp files after run"
• Include more details about motivation, results after summary
• Address your future self

Keeping track: status

echo "New stuff" > stuff/more.txt
git add stuff/more.txt
echo "More to read" >> README.md
git status # HEAD vs. index and index vs. disk

git-status       - Show the working tree status
On branch dylan/refactor
Changes to be committed:
  (use "git reset HEAD <file>..." to unstage)

	new file:   stuff/more.txt

Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git checkout -- <file>..." to discard changes in working directory)

	modified:   README.md

One last diff quick reference

`git diff REV1..[REV2] [-- PATH ...]`

REV1 vs. REV2 (HEAD)

`git diff [-- PATH ...]`

disk vs. index

`git diff REV [-- PATH ...]`

disk vs. REV

`git diff --cached [REV] [-- PATH ...]`

index vs. REV (HEAD)

git status is one of the most useful commands you can just run all the time. The top part is the difference between your current HEAD and index (things you can commit); the bottom is the difference beetween your index and the disk (things you can add).

(Un-)doing all the things: reset

Un-staging: undoing add, rm (repo to index)

`git reset [REV] -- PATH ...`

sets the index file entries match those from revision (HEAD)

`git reset -p`

ask interactively which changes to reset

Dash-dash pattern: separates revisions from paths, can be omitted if unambiguous

git reset -- stuff/more.txt

Unstaged changes after reset:
M	README.md

Index manipulation summary

↙	disk	index	repo
disk		`checkout`
index	`add`		`reset`
repo	`commit`

Un-comitting: changing which commit your branch points to

Changing where the current branch points

`git reset --soft REV`

point the current branch to REV, but nothing else (same files on disk, index)

`git reset --soft HEAD^`

undo the last `git commit` but keep my current changes, let my try again

`git commit --amend`

replace the current commit with the index, keeping the commit message

`git reset [--mixed] REV`

point current branch to REV, and also set index to match (but not disk)

(If you want to keep your changes but re-add them on a different commit)

`git reset --hard [REV]`

throw away everything (index+disk) and point current branch to REV

(HEAD: throw away all my work since last commit)

`reset` counts as "rewriting history" (like `rebase`): don't do this on branches shared with others

This is different than checkout which just changes HEAD itself (no indirection).

There are other ways to rewrite history as well, specifically git rebase...

Combining changes on commits/branches: merging

git status
git branch -va

On branch dylan/refactor
Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git checkout -- <file>..." to discard changes in working directory)

	modified:   README.md

Untracked files:
  (use "git add <file>..." to include in what will be committed)

	stuff/more.txt

no changes added to commit (use "git add" and/or "git commit -a")
* dylan/refactor e4212ad Mark down 'README'; no more other.txt
  master         0b5bcf3 Improve README with new stuff

git checkout -m master
git status

M	README
Switched to branch 'master'
On branch master
Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git checkout -- <file>..." to discard changes in working directory)

	modified:   README

Untracked files:
  (use "git add <file>..." to include in what will be committed)

	stuff/more.txt

no changes added to commit (use "git add" and/or "git commit -a")

git diff

diff --git a/README b/README
index f25e220..7074c76 100644
--- a/README
+++ b/README
@@ -1 +1,2 @@
 New and improved.
+More to read

git add .
git commit -m "Add more and more"

[master dc7e13a] Add more and more
 2 files changed, 2 insertions(+)
 create mode 100644 stuff/more.txt

git show-branch

git-show-branch  - Show branches and their commits
! [dylan/refactor] Mark down 'README'; no more other.txt
 * [master] Add more and more
--
 * [master] Add more and more
+  [dylan/refactor] Mark down 'README'; no more other.txt
+* [master^] Improve README with new stuff

git merge dylan/refactor

git-merge        - Join two or more development histories together
Removing stuff/other.txt
Merge made by the 'recursive' strategy.
 README => README.md | 0
 stuff/other.txt     | 1 -
 2 files changed, 1 deletion(-)
 rename README => README.md (100%)
 delete mode 100644 stuff/other.txt

git log --graph -4

*   commit f449e53c83fd0de9a94c36b271ce4a7c675ea92f (HEAD -> master)
|\  Merge: dc7e13a e4212ad
| | Author: Dylan Simon <dylan@dylex.net>
| | Date:   Fri Jun 30 14:00:00 2017
| | 
| |     Merge branch 'dylan/refactor'
| | 
| * commit e4212ad336cbaf2c4a5b454af07a484b1b09b83b (dylan/refactor)
| | Author: Dylan Simon <dylan@dylex.net>
| | Date:   Fri Jun 30 13:00:00 2017
| | 
| |     Mark down 'README'; no more other.txt
| | 
* | commit dc7e13a6ad09aca550d5179dcce8f82bc44255a9
|/  Author: Dylan Simon <dylan@dylex.net>
|   Date:   Fri Jun 30 14:00:00 2017
|   
|       Add more and more
| 
* commit 0b5bcf36d47bf5abc4ec35c72e9a2c0294d8d832 (tag: scicon17)
| Author: Dylan Simon <dylan@dylex.net>
| Date:   Thu Jun 22 15:00:00 2017
| 
|     Improve README with new stuff

Dealing with merge conflicts

If the two branches cannot be combined cleanly (conflicting changes)...

• Manually edit files with conflict markers and git add result
• git mergetool: interactively resolve conflicts based on both sets of changes

Commits derived from other commits

Add a "reversed" commit: revert

git revert e4212ad

git-revert       - Revert some existing commits
[master 3fd3795] Revert "Mark down 'README'; no more other.txt"
 2 files changed, 1 insertion(+)
 rename README.md => README (100%)
 create mode 100644 stuff/other.txt

Graft a "forward" commit: cherry-pick

If I wanted to un-revert that change, I could just git revert it again. Alternatively, I could re-apply the original commit, which is more common when wanting to take a few commits from someone else's branch, without merging the whole branch.

git cherry-pick e4212ad

git-cherry-pick  - Apply the changes introduced by some existing commits
[master 5482448] Mark down 'README'; no more other.txt
 Date: Fri Jun 30 13:00:00 2017 -0400
 2 files changed, 1 deletion(-)
 rename README => README.md (100%)
 delete mode 100644 stuff/other.txt

git log -2

commit 5482448f59a5f7ea2e488a9f1f077e5d0d3cfe37 (HEAD -> master)
Author: Dylan Simon <dylan@dylex.net>
Date:   Fri Jun 30 13:00:00 2017

    Mark down 'README'; no more other.txt

commit 3fd3795a58b28d39b4ae8b0cec8f70e26c6eaaf4
Author: Dylan Simon <dylan@dylex.net>
Date:   Fri Jun 30 14:00:00 2017

    Revert "Mark down 'README'; no more other.txt"
    
    This reverts commit e4212ad336cbaf2c4a5b454af07a484b1b09b83b.

Wrapping things up: cleaning and stashing

touch output.txt
git status

On branch master
Untracked files:
  (use "git add <file>..." to include in what will be committed)

	output.txt

nothing added to commit but untracked files present (use "git add" to track)

git clean -f

git-clean        - Remove untracked files from the working tree
Removing output.txt

echo "further reading" >> README.md
git status

On branch master
Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git checkout -- <file>..." to discard changes in working directory)

	modified:   README.md

no changes added to commit (use "git add" and/or "git commit -a")

If you have some local chages, but you want to do something else for a minute (e.g., pull new changes, try something else, etc.), rather than copying your changes to a temp file, or creating a whole new branch (which is also perfectly reasonable, but a few extra steps), there is a stack of light-weight commits you can push and pop from.

git stash #push
git stash list

git-stash        - Stash the changes in a dirty working directory away
Saved working directory and index state WIP on master: 5482448 Mark down 'README'; no more other.txt
stash@{0}: WIP on master: 5482448 Mark down 'README'; no more other.txt

git stash pop

On branch master
Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git checkout -- <file>..." to discard changes in working directory)

	modified:   README.md

no changes added to commit (use "git add" and/or "git commit -a")
Dropped refs/stash@{0} (2a4c13ea91689e4e2258ca24715088c9c52ef411)

Rewriting history: rebase

• git rebase [COMMIT]: attempt to linearize history (flatten merges) on top of COMMIT (upstream branch)
• git rebase -i [COMMIT]: use a text editor to reorder or combine commits since COMMIT
• Any rebased commits have different hashes -- git won't realize they're the same
• Only rebase (or reset) unshared commits (or with agreement from everyone else)

Rebase is a powerful way of changing the shape or order of history (that is, the parents in the commit graph) while trying to preserve the same effects. However, since it changes parents, it changes the resulting commit hashes, so the result will be incompatible with the un-rebased commits.

git merge master, then git rebase master

Browsing history

cat README.md
git blame -- README.md

New and improved.
More to read
further reading
git-blame        - Show what revision and author last modified each line of a file
0b5bcf36 README    (Dylan Simon       2017-06-22 15:00:00 -0400 1) New and improved.
dc7e13a6 README    (Dylan Simon       2017-06-30 14:00:00 -0400 2) More to read
00000000 README.md (Not Committed Yet 2017-10-17 11:02:20 -0400 3) further reading

git checkout -- README.md

Making git ignore files

Generated output, temporary files, etc.

echo '/output.*' > .gitignore
git add .gitignore
git commit -m 'Ignore all output files in top dir'
touch output.txt
git status

[master 7dfd4e5] Ignore all output files in top dir
 1 file changed, 1 insertion(+)
 create mode 100644 .gitignore
On branch master
nothing to commit, working tree clean

Ignore patterns:

• /*.out: only in this directory
• *.out: anywhere in this directory or below
• *.out/: only directories (not files)
• !this.out: cancel ignore

Ignore file lists:

• .gitignore: in repository, for every instance of this repo
• ~/.config/git/ignore: for you only, in all your git repos
• .git/info/include: for you only, in this repo

git clean -fx

Removing output.txt

Part 3: Remote Collaboration

Playing well with others

So far we've just talked about one git repository. The conceptual extention to moving data between multiple repositories is quite simple, but does involve a number of new commands.

remote repositories

file path, sshable host ([user@]host:/path), or URL (git: or https:)

git remote add ghdylex git://github.com/dylex/git-structure-tutorial
git remote -v

git-remote       - Manage set of tracked repositories
ghdylex	git://github.com/dylex/git-structure-tutorial (fetch)
ghdylex	git://github.com/dylex/git-structure-tutorial (push)

Each repository has a set of "remotes", each associating a name with a URL. Or really two URLs: one to fetch (download) and one to push (upload).

git fetch ghdylex # or: git remote update

git-fetch        - Download objects and refs from another repository
remote: Counting objects: 150, done.
remote: Compressing objects: 100% (71/71), done.
remote: Total 150 (delta 68), reused 140 (delta 58), pack-reused 0
Receiving objects: 100% (150/150), 1.01 MiB | 14.30 MiB/s, done.
Resolving deltas: 100% (68/68), done.
From git://github.com/dylex/git-structure-tutorial
 * [new branch]      example    -> ghdylex/example
 * [new branch]      gh-pages   -> ghdylex/gh-pages
 * [new branch]      master     -> ghdylex/master

fetch: download each remote refs/heads/BRANCH to refs/remotes/REMOTE/BRANCH tracking branch

git branch -va

  dylan/refactor           e4212ad Mark down 'README'; no more other.txt
* master                   7dfd4e5 Ignore all output files in top dir
  remotes/ghdylex/example  f79c7b3 Add a period.
  remotes/ghdylex/gh-pages 2baf8b1 Update generated slides from 22e48c0
  remotes/ghdylex/master   22e48c0 Add section on rebase

git merge ghdylex/example

Merge made by the 'recursive' strategy.
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

git pull ghdylex example

git-pull         - Fetch from and integrate with another repository or a local branch
From git://github.com/dylex/git-structure-tutorial
 * branch            example    -> FETCH_HEAD
Already up-to-date.

git fetch ; git merge is such a common workflow that one command can do both

Uploading: push

! git push ghdylex master

git-push         - Update remote refs along with associated objects
fatal: remote error: 
  You can't push to git://github.com/dylex/git-structure-tutorial.git
  Use https://github.com/dylex/git-structure-tutorial.git

quick reference: remote send/receive

`git fetch -p`, `--prune`

also delete `refs/remotes/*` missing on remote

`git push REMOTE [SRCREF:]BRANCH`

update the remote `refs/heads/BRANCH` to `SRCREF`

`git push -u ...`

set the default for *pull* and *push* on current branch (see config)

`git checkout|branch -t BRANCH`

set default *pull* tracking source (default for *checkout* when no local branch)

`git push --force ...`

like remote *reset*, can remove commits (don't do this! why not?)

`git push REMOTE :BRANCH`

delete remote branch

Unlike branches, tags (even though they are both just references) are assumed to be immutable, so fetch --tags just puts them under refs/tags, not refs/remotes.

git log --graph

*   commit 7098d57271ab38aea12fa2381b85e91c29f98789 (HEAD -> master)
|\  Merge: 7dfd4e5 f79c7b3
| | Author: Dylan Simon <dylan@dylex.net>
| | Date:   Fri Jun 30 14:00:00 2017
| | 
| |     Merge remote-tracking branch 'ghdylex/example'
| | 
| * commit f79c7b3fbb14f1664adeec9e5a6a36b023b5c171 (ghdylex/example)
| | Author: Dylan Simon <dylan@dylex.net>
| | Date:   Mon Oct 16 14:13:31 2017
| | 
| |     Add a period.
| | 
* | commit 7dfd4e5f1c0d4aaf481326f5f3edbb008bcabf12
|/  Author: Dylan Simon <dylan@dylex.net>
|   Date:   Fri Jun 30 14:00:00 2017
|   
|       Ignore all output files in top dir
| 
* commit 5482448f59a5f7ea2e488a9f1f077e5d0d3cfe37
| Author: Dylan Simon <dylan@dylex.net>
| Date:   Fri Jun 30 13:00:00 2017
| 
|     Mark down 'README'; no more other.txt
| 
* commit 3fd3795a58b28d39b4ae8b0cec8f70e26c6eaaf4
| Author: Dylan Simon <dylan@dylex.net>
| Date:   Fri Jun 30 14:00:00 2017
| 
|     Revert "Mark down 'README'; no more other.txt"
|     
|     This reverts commit e4212ad336cbaf2c4a5b454af07a484b1b09b83b.
|   
*   commit f449e53c83fd0de9a94c36b271ce4a7c675ea92f
|\  Merge: dc7e13a e4212ad
| | Author: Dylan Simon <dylan@dylex.net>
| | Date:   Fri Jun 30 14:00:00 2017
| | 
| |     Merge branch 'dylan/refactor'
| | 
| * commit e4212ad336cbaf2c4a5b454af07a484b1b09b83b (dylan/refactor)
| | Author: Dylan Simon <dylan@dylex.net>
| | Date:   Fri Jun 30 13:00:00 2017
| | 
| |     Mark down 'README'; no more other.txt
| | 
* | commit dc7e13a6ad09aca550d5179dcce8f82bc44255a9
|/  Author: Dylan Simon <dylan@dylex.net>
|   Date:   Fri Jun 30 14:00:00 2017
|   
|       Add more and more
| 
* commit 0b5bcf36d47bf5abc4ec35c72e9a2c0294d8d832 (tag: scicon17)
| Author: Dylan Simon <dylan@dylex.net>
| Date:   Thu Jun 22 15:00:00 2017
| 
|     Improve README with new stuff
| 
* commit 2efdb20ab8b7d2e585ae0cd4209f9c4c525d94e1
  Author: Dylan Simon <dylan@dylex.net>
  Date:   Tue Jun 20 18:00:00 2017
  
      Add some text files to my tree

Back to the beginning: clone

git clone git://github.com/dylex/git-structure-tutorial

git-clone        - Clone a repository into a new directory
Cloning into 'git-structure-tutorial'...
remote: Counting objects: 171, done.
remote: Compressing objects: 100% (45/45), done.
remote: Total 171 (delta 39), reused 76 (delta 31), pack-reused 85
Receiving objects: 100% (171/171), 1.16 MiB | 16.93 MiB/s, done.
Resolving deltas: 100% (67/67), done.

git -C git-structure-tutorial branch -va

* master                  22e48c0 Add section on rebase
  remotes/origin/HEAD     -> origin/master
  remotes/origin/example  f79c7b3 Add a period.
  remotes/origin/gh-pages 2baf8b1 Update generated slides from 22e48c0
  remotes/origin/master   22e48c0 Add section on rebase

clone is equivalent to:

• git init DIR (default to repo basename, set with git clone URL DIR)
• git remote add origin URL (-o REMOTE sets name)
• git fetch REMOTE
• git checkout master (-b BRANCH sets branch) or git checkout -b BRANCH -t REMOTE/BRANCH

Practical workflow

• git pull
• edit edit, git status, edit edit
• git commit -a
• git push
• repeat

Future topics

• github
  • github.com/flatironinstitute (contact SCC to join)
  • gh-pages (user/repo gh-pages branch published as user.github.io/repo)
  • issues, pull requests, workflows
  • permissions
  • web hooks
• branching/tagging strategies
• code structure
• documentation
• continuous integration

Nelson Elhage & Anders Kaseorg's Understanding Git

git help core-tutorial

GITCORE-TUTORIAL(7)               Git Manual               GITCORE-TUTORIAL(7)

NNAAMMEE
       gitcore-tutorial - A Git core tutorial for developers

SSYYNNOOPPSSIISS
       git *

DDEESSCCRRIIPPTTIIOONN
       This tutorial explains how to use the "core" Git commands to set up and
       work with a Git repository.

       If you just need to use Git as a revision control system you may prefer
       to start with "A Tutorial Introduction to Git" (ggiittttuuttoorriiaall(7)) or tthhee
       GGiitt UUsseerr MMaannuuaall[1].

       However, an understanding of these low-level tools can be helpful if
       you want to understand Git’s internals.

       The core Git is often called "plumbing", with the prettier user
       interfaces on top of it called "porcelain". You may not want to use the
       plumbing directly very often, but it can be good to know what the
       plumbing does when the porcelain isn’t flushing.

       Back when this document was originally written, many porcelain commands
       were shell scripts. For simplicity, it still uses them as examples to
       illustrate how plumbing is fit together to form the porcelain commands.
       The source tree includes some of these scripts in contrib/examples/ for
       reference. Although these are not implemented as shell scripts anymore,
       the description of what the plumbing layer commands do is still valid.

           NNoottee
           Deeper technical details are often marked as Notes, which you can
           skip on your first reading.

CCRREEAATTIINNGG AA GGIITT RREEPPOOSSIITTOORRYY
       Creating a new Git repository couldn’t be easier: all Git repositories
       start out empty, and the only thing you need to do is find yourself a
       subdirectory that you want to use as a working tree - either an empty
       one for a totally new project, or an existing working tree that you
       want to import into Git.

       For our first example, we’re going to start a totally new repository
       from scratch, with no pre-existing files, and we’ll call it
       _g_i_t_-_t_u_t_o_r_i_a_l. To start up, create a subdirectory for it, change into
       that subdirectory, and initialize the Git infrastructure with _g_i_t _i_n_i_t:

           $ mkdir git-tutorial
           $ cd git-tutorial
           $ git init

       to which Git will reply

           Initialized empty Git repository in .git/

       which is just Git’s way of saying that you haven’t been doing anything
       strange, and that it will have created a local ..ggiitt directory setup for
       your new project. You will now have a ..ggiitt directory, and you can
       inspect that with _l_s. For your new empty project, it should show you
       three entries, among other things:

       ·   a file called HHEEAADD, that has rreeff:: rreeffss//hheeaaddss//mmaasstteerr in it. This is
           similar to a symbolic link and points at rreeffss//hheeaaddss//mmaasstteerr relative
           to the HHEEAADD file.

           Don’t worry about the fact that the file that the HHEEAADD link points
           to doesn’t even exist yet — you haven’t created the commit that
           will start your HHEEAADD development branch yet.

       ·   a subdirectory called oobbjjeeccttss, which will contain all the objects
           of your project. You should never have any real reason to look at
           the objects directly, but you might want to know that these objects
           are what contains all the real _d_a_t_a in your repository.

       ·   a subdirectory called rreeffss, which contains references to objects.

       In particular, the rreeffss subdirectory will contain two other
       subdirectories, named hheeaaddss and ttaaggss respectively. They do exactly what
       their names imply: they contain references to any number of different
       _h_e_a_d_s of development (aka _b_r_a_n_c_h_e_s), and to any _t_a_g_s that you have
       created to name specific versions in your repository.

       One note: the special mmaasstteerr head is the default branch, which is why
       the ..ggiitt//HHEEAADD file was created points to it even if it doesn’t yet
       exist. Basically, the HHEEAADD link is supposed to always point to the
       branch you are working on right now, and you always start out expecting
       to work on the mmaasstteerr branch.

       However, this is only a convention, and you can name your branches
       anything you want, and don’t have to ever even _h_a_v_e a mmaasstteerr branch. A
       number of the Git tools will assume that ..ggiitt//HHEEAADD is valid, though.

           NNoottee
           An _o_b_j_e_c_t is identified by its 160-bit SHA-1 hash, aka _o_b_j_e_c_t _n_a_m_e,
           and a reference to an object is always the 40-byte hex
           representation of that SHA-1 name. The files in the rreeffss
           subdirectory are expected to contain these hex references (usually
           with a final \\nn at the end), and you should thus expect to see a
           number of 41-byte files containing these references in these rreeffss
           subdirectories when you actually start populating your tree.

           NNoottee
           An advanced user may want to take a look at ggiittrreeppoossiittoorryy--llaayyoouutt(5)
           after finishing this tutorial.

       You have now created your first Git repository. Of course, since it’s
       empty, that’s not very useful, so let’s start populating it with data.

PPOOPPUULLAATTIINNGG AA GGIITT RREEPPOOSSIITTOORRYY
       We’ll keep this simple and stupid, so we’ll start off with populating a
       few trivial files just to get a feel for it.

       Start off with just creating any random files that you want to maintain
       in your Git repository. We’ll start off with a few bad examples, just
       to get a feel for how this works:

           $ echo "Hello World" >hello
           $ echo "Silly example" >example

       you have now created two files in your working tree (aka _w_o_r_k_i_n_g
       _d_i_r_e_c_t_o_r_y), but to actually check in your hard work, you will have to
       go through two steps:

       ·   fill in the _i_n_d_e_x file (aka _c_a_c_h_e) with the information about your
           working tree state.

       ·   commit that index file as an object.

       The first step is trivial: when you want to tell Git about any changes
       to your working tree, you use the _g_i_t _u_p_d_a_t_e_-_i_n_d_e_x program. That
       program normally just takes a list of filenames you want to update, but
       to avoid trivial mistakes, it refuses to add new entries to the index
       (or remove existing ones) unless you explicitly tell it that you’re
       adding a new entry with the ----aadddd flag (or removing an entry with the
       ----rreemmoovvee) flag.

       So to populate the index with the two files you just created, you can
       do

           $ git update-index --add hello example

       and you have now told Git to track those two files.

       In fact, as you did that, if you now look into your object directory,
       you’ll notice that Git will have added two new objects to the object
       database. If you did exactly the steps above, you should now be able to
       do

           $ ls .git/objects/??/*

       and see two files:

           .git/objects/55/7db03de997c86a4a028e1ebd3a1ceb225be238
           .git/objects/f2/4c74a2e500f5ee1332c86b94199f52b1d1d962

       which correspond with the objects with names of 555577ddbb...... and ff2244cc77......
       respectively.

       If you want to, you can use _g_i_t _c_a_t_-_f_i_l_e to look at those objects, but
       you’ll have to use the object name, not the filename of the object:

           $ git cat-file -t 557db03de997c86a4a028e1ebd3a1ceb225be238

       where the --tt tells _g_i_t _c_a_t_-_f_i_l_e to tell you what the "type" of the
       object is. Git will tell you that you have a "blob" object (i.e., just
       a regular file), and you can see the contents with

           $ git cat-file blob 557db03

       which will print out "Hello World". The object 555577ddbb0033 is nothing more
       than the contents of your file hheelllloo.

           NNoottee
           Don’t confuse that object with the file hheelllloo itself. The object is
           literally just those specific ccoonntteennttss of the file, and however
           much you later change the contents in file hheelllloo, the object we
           just looked at will never change. Objects are immutable.

           NNoottee
           The second example demonstrates that you can abbreviate the object
           name to only the first several hexadecimal digits in most places.

       Anyway, as we mentioned previously, you normally never actually take a
       look at the objects themselves, and typing long 40-character hex names
       is not something you’d normally want to do. The above digression was
       just to show that _g_i_t _u_p_d_a_t_e_-_i_n_d_e_x did something magical, and actually
       saved away the contents of your files into the Git object database.

       Updating the index did something else too: it created a ..ggiitt//iinnddeexx
       file. This is the index that describes your current working tree, and
       something you should be very aware of. Again, you normally never worry
       about the index file itself, but you should be aware of the fact that
       you have not actually really "checked in" your files into Git so far,
       you’ve only ttoolldd Git about them.

       However, since Git knows about them, you can now start using some of
       the most basic Git commands to manipulate the files or look at their
       status.

       In particular, let’s not even check in the two files into Git yet,
       we’ll start off by adding another line to hheelllloo first:

           $ echo "It's a new day for git" >>hello

       and you can now, since you told Git about the previous state of hheelllloo,
       ask Git what has changed in the tree compared to your old index, using
       the _g_i_t _d_i_f_f_-_f_i_l_e_s command:

           $ git diff-files

       Oops. That wasn’t very readable. It just spit out its own internal
       version of a _d_i_f_f, but that internal version really just tells you that
       it has noticed that "hello" has been modified, and that the old object
       contents it had have been replaced with something else.

       To make it readable, we can tell _g_i_t _d_i_f_f_-_f_i_l_e_s to output the
       differences as a patch, using the --pp flag:

           $ git diff-files -p
           diff --git a/hello b/hello
           index 557db03..263414f 100644
           --- a/hello
           +++ b/hello
           @@ -1 +1,2 @@
            Hello World
           +It's a new day for git

       i.e. the diff of the change we caused by adding another line to hheelllloo.

       In other words, _g_i_t _d_i_f_f_-_f_i_l_e_s always shows us the difference between
       what is recorded in the index, and what is currently in the working
       tree. That’s very useful.

       A common shorthand for ggiitt ddiiffff--ffiilleess --pp is to just write ggiitt ddiiffff,
       which will do the same thing.

           $ git diff
           diff --git a/hello b/hello
           index 557db03..263414f 100644
           --- a/hello
           +++ b/hello
           @@ -1 +1,2 @@
            Hello World
           +It's a new day for git

CCOOMMMMIITTTTIINNGG GGIITT SSTTAATTEE
       Now, we want to go to the next stage in Git, which is to take the files
       that Git knows about in the index, and commit them as a real tree. We
       do that in two phases: creating a _t_r_e_e object, and committing that _t_r_e_e
       object as a _c_o_m_m_i_t object together with an explanation of what the tree
       was all about, along with information of how we came to that state.

       Creating a tree object is trivial, and is done with _g_i_t _w_r_i_t_e_-_t_r_e_e.
       There are no options or other input: ggiitt wwrriittee--ttrreeee will take the
       current index state, and write an object that describes that whole
       index. In other words, we’re now tying together all the different
       filenames with their contents (and their permissions), and we’re
       creating the equivalent of a Git "directory" object:

           $ git write-tree

       and this will just output the name of the resulting tree, in this case
       (if you have done exactly as I’ve described) it should be

           8988da15d077d4829fc51d8544c097def6644dbb

       which is another incomprehensible object name. Again, if you want to,
       you can use ggiitt ccaatt--ffiillee --tt 88998888dd...... to see that this time the object
       is not a "blob" object, but a "tree" object (you can also use ggiitt
       ccaatt--ffiillee to actually output the raw object contents, but you’ll see
       mainly a binary mess, so that’s less interesting).

       However — normally you’d never use _g_i_t _w_r_i_t_e_-_t_r_e_e on its own, because
       normally you always commit a tree into a commit object using the _g_i_t
       _c_o_m_m_i_t_-_t_r_e_e command. In fact, it’s easier to not actually use _g_i_t
       _w_r_i_t_e_-_t_r_e_e on its own at all, but to just pass its result in as an
       argument to _g_i_t _c_o_m_m_i_t_-_t_r_e_e.

       _g_i_t _c_o_m_m_i_t_-_t_r_e_e normally takes several arguments — it wants to know
       what the _p_a_r_e_n_t of a commit was, but since this is the first commit
       ever in this new repository, and it has no parents, we only need to
       pass in the object name of the tree. However, _g_i_t _c_o_m_m_i_t_-_t_r_e_e also
       wants to get a commit message on its standard input, and it will write
       out the resulting object name for the commit to its standard output.

       And this is where we create the ..ggiitt//rreeffss//hheeaaddss//mmaasstteerr file which is
       pointed at by HHEEAADD. This file is supposed to contain the reference to
       the top-of-tree of the master branch, and since that’s exactly what _g_i_t
       _c_o_m_m_i_t_-_t_r_e_e spits out, we can do this all with a sequence of simple
       shell commands:

           $ tree=$(git write-tree)
           $ commit=$(echo 'Initial commit' | git commit-tree $tree)
           $ git update-ref HEAD $commit

       In this case this creates a totally new commit that is not related to
       anything else. Normally you do this only oonnccee for a project ever, and
       all later commits will be parented on top of an earlier commit.

       Again, normally you’d never actually do this by hand. There is a
       helpful script called ggiitt ccoommmmiitt that will do all of this for you. So
       you could have just written ggiitt ccoommmmiitt instead, and it would have done
       the above magic scripting for you.

MMAAKKIINNGG AA CCHHAANNGGEE
       Remember how we did the _g_i_t _u_p_d_a_t_e_-_i_n_d_e_x on file hheelllloo and then we
       changed hheelllloo afterward, and could compare the new state of hheelllloo with
       the state we saved in the index file?

       Further, remember how I said that _g_i_t _w_r_i_t_e_-_t_r_e_e writes the contents of
       the iinnddeexx file to the tree, and thus what we just committed was in fact
       the oorriiggiinnaall contents of the file hheelllloo, not the new ones. We did that
       on purpose, to show the difference between the index state, and the
       state in the working tree, and how they don’t have to match, even when
       we commit things.

       As before, if we do ggiitt ddiiffff--ffiilleess --pp in our git-tutorial project,
       we’ll still see the same difference we saw last time: the index file
       hasn’t changed by the act of committing anything. However, now that we
       have committed something, we can also learn to use a new command: _g_i_t
       _d_i_f_f_-_i_n_d_e_x.

       Unlike _g_i_t _d_i_f_f_-_f_i_l_e_s, which showed the difference between the index
       file and the working tree, _g_i_t _d_i_f_f_-_i_n_d_e_x shows the differences between
       a committed ttrreeee and either the index file or the working tree. In
       other words, _g_i_t _d_i_f_f_-_i_n_d_e_x wants a tree to be diffed against, and
       before we did the commit, we couldn’t do that, because we didn’t have
       anything to diff against.

       But now we can do

           $ git diff-index -p HEAD

       (where --pp has the same meaning as it did in _g_i_t _d_i_f_f_-_f_i_l_e_s), and it
       will show us the same difference, but for a totally different reason.
       Now we’re comparing the working tree not against the index file, but
       against the tree we just wrote. It just so happens that those two are
       obviously the same, so we get the same result.

       Again, because this is a common operation, you can also just shorthand
       it with

           $ git diff HEAD

       which ends up doing the above for you.

       In other words, _g_i_t _d_i_f_f_-_i_n_d_e_x normally compares a tree against the
       working tree, but when given the ----ccaacchheedd flag, it is told to instead
       compare against just the index cache contents, and ignore the current
       working tree state entirely. Since we just wrote the index file to
       HEAD, doing ggiitt ddiiffff--iinnddeexx ----ccaacchheedd --pp HHEEAADD should thus return an empty
       set of differences, and that’s exactly what it does.

           NNoottee
           _g_i_t _d_i_f_f_-_i_n_d_e_x really always uses the index for its comparisons,
           and saying that it compares a tree against the working tree is thus
           not strictly accurate. In particular, the list of files to compare
           (the "meta-data") aallwwaayyss comes from the index file, regardless of
           whether the ----ccaacchheedd flag is used or not. The ----ccaacchheedd flag really
           only determines whether the file ccoonntteennttss to be compared come from
           the working tree or not.

           This is not hard to understand, as soon as you realize that Git
           simply never knows (or cares) about files that it is not told about
           explicitly. Git will never go llooookkiinngg for files to compare, it
           expects you to tell it what the files are, and that’s what the
           index is there for.

       However, our next step is to commit the cchhaannggee we did, and again, to
       understand what’s going on, keep in mind the difference between
       "working tree contents", "index file" and "committed tree". We have
       changes in the working tree that we want to commit, and we always have
       to work through the index file, so the first thing we need to do is to
       update the index cache:

           $ git update-index hello

       (note how we didn’t need the ----aadddd flag this time, since Git knew about
       the file already).

       Note what happens to the different _g_i_t _d_i_f_f_-_* versions here. After
       we’ve updated hheelllloo in the index, ggiitt ddiiffff--ffiilleess --pp now shows no
       differences, but ggiitt ddiiffff--iinnddeexx --pp HHEEAADD still ddooeess show that the
       current state is different from the state we committed. In fact, now
       _g_i_t _d_i_f_f_-_i_n_d_e_x shows the same difference whether we use the ----ccaacchheedd
       flag or not, since now the index is coherent with the working tree.

       Now, since we’ve updated hheelllloo in the index, we can commit the new
       version. We could do it by writing the tree by hand again, and
       committing the tree (this time we’d have to use the --pp HHEEAADD flag to
       tell commit that the HEAD was the ppaarreenntt of the new commit, and that
       this wasn’t an initial commit any more), but you’ve done that once
       already, so let’s just use the helpful script this time:

           $ git commit

       which starts an editor for you to write the commit message and tells
       you a bit about what you have done.

       Write whatever message you want, and all the lines that start with _#
       will be pruned out, and the rest will be used as the commit message for
       the change. If you decide you don’t want to commit anything after all
       at this point (you can continue to edit things and update the index),
       you can just leave an empty message. Otherwise ggiitt ccoommmmiitt will commit
       the change for you.

       You’ve now made your first real Git commit. And if you’re interested in
       looking at what ggiitt ccoommmmiitt really does, feel free to investigate: it’s
       a few very simple shell scripts to generate the helpful (?) commit
       message headers, and a few one-liners that actually do the commit
       itself (_g_i_t _c_o_m_m_i_t).

IINNSSPPEECCTTIINNGG CCHHAANNGGEESS
       While creating changes is useful, it’s even more useful if you can tell
       later what changed. The most useful command for this is another of the
       _d_i_f_f family, namely _g_i_t _d_i_f_f_-_t_r_e_e.

       _g_i_t _d_i_f_f_-_t_r_e_e can be given two arbitrary trees, and it will tell you
       the differences between them. Perhaps even more commonly, though, you
       can give it just a single commit object, and it will figure out the
       parent of that commit itself, and show the difference directly. Thus,
       to get the same diff that we’ve already seen several times, we can now
       do

           $ git diff-tree -p HEAD

       (again, --pp means to show the difference as a human-readable patch), and
       it will show what the last commit (in HHEEAADD) actually changed.

           NNoottee
           Here is an ASCII art by Jon Loeliger that illustrates how various
           _d_i_f_f_-_* commands compare things.

                           diff-tree
                            +----+
                            |    |
                            |    |
                            V    V
                         +-----------+
                         | Object DB |
                         |  Backing  |
                         |   Store   |
                         +-----------+
                           ^    ^
                           |    |
                           |    |  diff-index --cached
                           |    |
               diff-index  |    V
                           |  +-----------+
                           |  |   Index   |
                           |  |  "cache"  |
                           |  +-----------+
                           |    ^
                           |    |
                           |    |  diff-files
                           |    |
                           V    V
                         +-----------+
                         |  Working  |
                         | Directory |
                         +-----------+

       More interestingly, you can also give _g_i_t _d_i_f_f_-_t_r_e_e the ----pprreettttyy flag,
       which tells it to also show the commit message and author and date of
       the commit, and you can tell it to show a whole series of diffs.
       Alternatively, you can tell it to be "silent", and not show the diffs
       at all, but just show the actual commit message.

       In fact, together with the _g_i_t _r_e_v_-_l_i_s_t program (which generates a list
       of revisions), _g_i_t _d_i_f_f_-_t_r_e_e ends up being a veritable fount of
       changes. You can emulate ggiitt lloogg, ggiitt lloogg --pp, etc. with a trivial
       script that pipes the output of ggiitt rreevv--lliisstt to ggiitt ddiiffff--ttrreeee ----ssttddiinn,
       which was exactly how early versions of ggiitt lloogg were implemented.

TTAAGGGGIINNGG AA VVEERRSSIIOONN
       In Git, there are two kinds of tags, a "light" one, and an "annotated
       tag".

       A "light" tag is technically nothing more than a branch, except we put
       it in the ..ggiitt//rreeffss//ttaaggss// subdirectory instead of calling it a hheeaadd. So
       the simplest form of tag involves nothing more than

           $ git tag my-first-tag

       which just writes the current HHEEAADD into the ..ggiitt//rreeffss//ttaaggss//mmyy--ffiirrsstt--ttaagg
       file, after which point you can then use this symbolic name for that
       particular state. You can, for example, do

           $ git diff my-first-tag

       to diff your current state against that tag which at this point will
       obviously be an empty diff, but if you continue to develop and commit
       stuff, you can use your tag as an "anchor-point" to see what has
       changed since you tagged it.

       An "annotated tag" is actually a real Git object, and contains not only
       a pointer to the state you want to tag, but also a small tag name and
       message, along with optionally a PGP signature that says that yes, you
       really did that tag. You create these annotated tags with either the --aa
       or --ss flag to _g_i_t _t_a_g:

           $ git tag -s <tagname>

       which will sign the current HHEEAADD (but you can also give it another
       argument that specifies the thing to tag, e.g., you could have tagged
       the current mmyybbrraanncchh point by using ggiitt ttaagg <<ttaaggnnaammee>> mmyybbrraanncchh).

       You normally only do signed tags for major releases or things like
       that, while the light-weight tags are useful for any marking you want
       to do — any time you decide that you want to remember a certain point,
       just create a private tag for it, and you have a nice symbolic name for
       the state at that point.

CCOOPPYYIINNGG RREEPPOOSSIITTOORRIIEESS
       Git repositories are normally totally self-sufficient and relocatable.
       Unlike CVS, for example, there is no separate notion of "repository"
       and "working tree". A Git repository normally iiss the working tree, with
       the local Git information hidden in the ..ggiitt subdirectory. There is
       nothing else. What you see is what you got.

           NNoottee
           You can tell Git to split the Git internal information from the
           directory that it tracks, but we’ll ignore that for now: it’s not
           how normal projects work, and it’s really only meant for special
           uses. So the mental model of "the Git information is always tied
           directly to the working tree that it describes" may not be
           technically 100% accurate, but it’s a good model for all normal
           use.

       This has two implications:

       ·   if you grow bored with the tutorial repository you created (or
           you’ve made a mistake and want to start all over), you can just do
           simple

               $ rm -rf git-tutorial

           and it will be gone. There’s no external repository, and there’s no
           history outside the project you created.

       ·   if you want to move or duplicate a Git repository, you can do so.
           There is _g_i_t _c_l_o_n_e command, but if all you want to do is just to
           create a copy of your repository (with all the full history that
           went along with it), you can do so with a regular ccpp --aa
           ggiitt--ttuuttoorriiaall nneeww--ggiitt--ttuuttoorriiaall.

           Note that when you’ve moved or copied a Git repository, your Git
           index file (which caches various information, notably some of the
           "stat" information for the files involved) will likely need to be
           refreshed. So after you do a ccpp --aa to create a new copy, you’ll
           want to do

               $ git update-index --refresh

           in the new repository to make sure that the index file is
           up-to-date.

       Note that the second point is true even across machines. You can
       duplicate a remote Git repository with aannyy regular copy mechanism, be
       it _s_c_p, _r_s_y_n_c or _w_g_e_t.

       When copying a remote repository, you’ll want to at a minimum update
       the index cache when you do this, and especially with other peoples'
       repositories you often want to make sure that the index cache is in
       some known state (you don’t know wwhhaatt they’ve done and not yet checked
       in), so usually you’ll precede the _g_i_t _u_p_d_a_t_e_-_i_n_d_e_x with a

           $ git read-tree --reset HEAD
           $ git update-index --refresh

       which will force a total index re-build from the tree pointed to by
       HHEEAADD. It resets the index contents to HHEEAADD, and then the _g_i_t
       _u_p_d_a_t_e_-_i_n_d_e_x makes sure to match up all index entries with the
       checked-out files. If the original repository had uncommitted changes
       in its working tree, ggiitt uuppddaattee--iinnddeexx ----rreeffrreesshh notices them and tells
       you they need to be updated.

       The above can also be written as simply

           $ git reset

       and in fact a lot of the common Git command combinations can be
       scripted with the ggiitt xxyyzz interfaces. You can learn things by just
       looking at what the various git scripts do. For example, ggiitt rreesseett used
       to be the above two lines implemented in _g_i_t _r_e_s_e_t, but some things
       like _g_i_t _s_t_a_t_u_s and _g_i_t _c_o_m_m_i_t are slightly more complex scripts around
       the basic Git commands.

       Many (most?) public remote repositories will not contain any of the
       checked out files or even an index file, and will oonnllyy contain the
       actual core Git files. Such a repository usually doesn’t even have the
       ..ggiitt subdirectory, but has all the Git files directly in the
       repository.

       To create your own local live copy of such a "raw" Git repository,
       you’d first create your own subdirectory for the project, and then copy
       the raw repository contents into the ..ggiitt directory. For example, to
       create your own copy of the Git repository, you’d do the following

           $ mkdir my-git
           $ cd my-git
           $ rsync -rL rsync://rsync.kernel.org/pub/scm/git/git.git/ .git

       followed by

           $ git read-tree HEAD

       to populate the index. However, now you have populated the index, and
       you have all the Git internal files, but you will notice that you don’t
       actually have any of the working tree files to work on. To get those,
       you’d check them out with

           $ git checkout-index -u -a

       where the --uu flag means that you want the checkout to keep the index
       up-to-date (so that you don’t have to refresh it afterward), and the --aa
       flag means "check out all files" (if you have a stale copy or an older
       version of a checked out tree you may also need to add the --ff flag
       first, to tell _g_i_t _c_h_e_c_k_o_u_t_-_i_n_d_e_x to ffoorrccee overwriting of any old
       files).

       Again, this can all be simplified with

           $ git clone git://git.kernel.org/pub/scm/git/git.git/ my-git
           $ cd my-git
           $ git checkout

       which will end up doing all of the above for you.

       You have now successfully copied somebody else’s (mine) remote
       repository, and checked it out.

CCRREEAATTIINNGG AA NNEEWW BBRRAANNCCHH
       Branches in Git are really nothing more than pointers into the Git
       object database from within the ..ggiitt//rreeffss// subdirectory, and as we
       already discussed, the HHEEAADD branch is nothing but a symlink to one of
       these object pointers.

       You can at any time create a new branch by just picking an arbitrary
       point in the project history, and just writing the SHA-1 name of that
       object into a file under ..ggiitt//rreeffss//hheeaaddss//. You can use any filename you
       want (and indeed, subdirectories), but the convention is that the
       "normal" branch is called mmaasstteerr. That’s just a convention, though, and
       nothing enforces it.

       To show that as an example, let’s go back to the git-tutorial
       repository we used earlier, and create a branch in it. You do that by
       simply just saying that you want to check out a new branch:

           $ git checkout -b mybranch

       will create a new branch based at the current HHEEAADD position, and switch
       to it.

           NNoottee
           If you make the decision to start your new branch at some other
           point in the history than the current HHEEAADD, you can do so by just
           telling _g_i_t _c_h_e_c_k_o_u_t what the base of the checkout would be. In
           other words, if you have an earlier tag or branch, you’d just do

               $ git checkout -b mybranch earlier-commit

           and it would create the new branch mmyybbrraanncchh at the earlier commit,
           and check out the state at that time.

       You can always just jump back to your original mmaasstteerr branch by doing

           $ git checkout master

       (or any other branch-name, for that matter) and if you forget which
       branch you happen to be on, a simple

           $ cat .git/HEAD

       will tell you where it’s pointing. To get the list of branches you
       have, you can say

           $ git branch

       which used to be nothing more than a simple script around llss
       ..ggiitt//rreeffss//hheeaaddss. There will be an asterisk in front of the branch you
       are currently on.

       Sometimes you may wish to create a new branch _w_i_t_h_o_u_t actually checking
       it out and switching to it. If so, just use the command

           $ git branch <branchname> [startingpoint]

       which will simply _c_r_e_a_t_e the branch, but will not do anything further.
       You can then later — once you decide that you want to actually develop
       on that branch — switch to that branch with a regular _g_i_t _c_h_e_c_k_o_u_t with
       the branchname as the argument.

MMEERRGGIINNGG TTWWOO BBRRAANNCCHHEESS
       One of the ideas of having a branch is that you do some (possibly
       experimental) work in it, and eventually merge it back to the main
       branch. So assuming you created the above mmyybbrraanncchh that started out
       being the same as the original mmaasstteerr branch, let’s make sure we’re in
       that branch, and do some work there.

           $ git checkout mybranch
           $ echo "Work, work, work" >>hello
           $ git commit -m "Some work." -i hello

       Here, we just added another line to hheelllloo, and we used a shorthand for
       doing both ggiitt uuppddaattee--iinnddeexx hheelllloo and ggiitt ccoommmmiitt by just giving the
       filename directly to ggiitt ccoommmmiitt, with an --ii flag (it tells Git to
       _i_n_c_l_u_d_e that file in addition to what you have done to the index file
       so far when making the commit). The --mm flag is to give the commit log
       message from the command line.

       Now, to make it a bit more interesting, let’s assume that somebody else
       does some work in the original branch, and simulate that by going back
       to the master branch, and editing the same file differently there:

           $ git checkout master

       Here, take a moment to look at the contents of hheelllloo, and notice how
       they don’t contain the work we just did in mmyybbrraanncchh — because that work
       hasn’t happened in the mmaasstteerr branch at all. Then do

           $ echo "Play, play, play" >>hello
           $ echo "Lots of fun" >>example
           $ git commit -m "Some fun." -i hello example

       since the master branch is obviously in a much better mood.

       Now, you’ve got two branches, and you decide that you want to merge the
       work done. Before we do that, let’s introduce a cool graphical tool
       that helps you view what’s going on:

           $ gitk --all

       will show you graphically both of your branches (that’s what the ----aallll
       means: normally it will just show you your current HHEEAADD) and their
       histories. You can also see exactly how they came to be from a common
       source.

       Anyway, let’s exit _g_i_t_k (^^QQ or the File menu), and decide that we want
       to merge the work we did on the mmyybbrraanncchh branch into the mmaasstteerr branch
       (which is currently our HHEEAADD too). To do that, there’s a nice script
       called _g_i_t _m_e_r_g_e, which wants to know which branches you want to
       resolve and what the merge is all about:

           $ git merge -m "Merge work in mybranch" mybranch

       where the first argument is going to be used as the commit message if
       the merge can be resolved automatically.

       Now, in this case we’ve intentionally created a situation where the
       merge will need to be fixed up by hand, though, so Git will do as much
       of it as it can automatically (which in this case is just merge the
       eexxaammppllee file, which had no differences in the mmyybbrraanncchh branch), and
       say:

                   Auto-merging hello
                   CONFLICT (content): Merge conflict in hello
                   Automatic merge failed; fix conflicts and then commit the result.

       It tells you that it did an "Automatic merge", which failed due to
       conflicts in hheelllloo.

       Not to worry. It left the (trivial) conflict in hheelllloo in the same form
       you should already be well used to if you’ve ever used CVS, so let’s
       just open hheelllloo in our editor (whatever that may be), and fix it up
       somehow. I’d suggest just making it so that hheelllloo contains all four
       lines:

           Hello World
           It's a new day for git
           Play, play, play
           Work, work, work

       and once you’re happy with your manual merge, just do a

           $ git commit -i hello

       which will very loudly warn you that you’re now committing a merge
       (which is correct, so never mind), and you can write a small merge
       message about your adventures in _g_i_t _m_e_r_g_e-land.

       After you’re done, start up ggiittkk ----aallll to see graphically what the
       history looks like. Notice that mmyybbrraanncchh still exists, and you can
       switch to it, and continue to work with it if you want to. The mmyybbrraanncchh
       branch will not contain the merge, but next time you merge it from the
       mmaasstteerr branch, Git will know how you merged it, so you’ll not have to
       do _t_h_a_t merge again.

       Another useful tool, especially if you do not always work in X-Window
       environment, is ggiitt sshhooww--bbrraanncchh.

           $ git show-branch --topo-order --more=1 master mybranch
           * [master] Merge work in mybranch
            ! [mybranch] Some work.
           --
           -  [master] Merge work in mybranch
           *+ [mybranch] Some work.
           *  [master^] Some fun.

       The first two lines indicate that it is showing the two branches with
       the titles of their top-of-the-tree commits, you are currently on
       mmaasstteerr branch (notice the asterisk ** character), and the first column
       for the later output lines is used to show commits contained in the
       mmaasstteerr branch, and the second column for the mmyybbrraanncchh branch. Three
       commits are shown along with their titles. All of them have non blank
       characters in the first column (** shows an ordinary commit on the
       current branch, -- is a merge commit), which means they are now part of
       the mmaasstteerr branch. Only the "Some work" commit has the plus ++ character
       in the second column, because mmyybbrraanncchh has not been merged to
       incorporate these commits from the master branch. The string inside
       brackets before the commit log message is a short name you can use to
       name the commit. In the above example, _m_a_s_t_e_r and _m_y_b_r_a_n_c_h are branch
       heads. _m_a_s_t_e_r_^ is the first parent of _m_a_s_t_e_r branch head. Please see
       ggiittrreevviissiioonnss(7) if you want to see more complex cases.

           NNoottee
           Without the _-_-_m_o_r_e_=_1 option, _g_i_t _s_h_o_w_-_b_r_a_n_c_h would not output the
           _[_m_a_s_t_e_r_^_] commit, as _[_m_y_b_r_a_n_c_h_] commit is a common ancestor of both
           _m_a_s_t_e_r and _m_y_b_r_a_n_c_h tips. Please see ggiitt--sshhooww--bbrraanncchh(1) for
           details.

           NNoottee
           If there were more commits on the _m_a_s_t_e_r branch after the merge,
           the merge commit itself would not be shown by _g_i_t _s_h_o_w_-_b_r_a_n_c_h by
           default. You would need to provide ----ssppaarrssee option to make the
           merge commit visible in this case.

       Now, let’s pretend you are the one who did all the work in mmyybbrraanncchh,
       and the fruit of your hard work has finally been merged to the mmaasstteerr
       branch. Let’s go back to mmyybbrraanncchh, and run _g_i_t _m_e_r_g_e to get the
       "upstream changes" back to your branch.

           $ git checkout mybranch
           $ git merge -m "Merge upstream changes." master

       This outputs something like this (the actual commit object names would
       be different)

           Updating from ae3a2da... to a80b4aa....
           Fast-forward (no commit created; -m option ignored)
            example | 1 +
            hello   | 1 +
            2 files changed, 2 insertions(+)

       Because your branch did not contain anything more than what had already
       been merged into the mmaasstteerr branch, the merge operation did not
       actually do a merge. Instead, it just updated the top of the tree of
       your branch to that of the mmaasstteerr branch. This is often called
       _f_a_s_t_-_f_o_r_w_a_r_d merge.

       You can run ggiittkk ----aallll again to see how the commit ancestry looks like,
       or run _s_h_o_w_-_b_r_a_n_c_h, which tells you this.

           $ git show-branch master mybranch
           ! [master] Merge work in mybranch
            * [mybranch] Merge work in mybranch
           --
           -- [master] Merge work in mybranch

MMEERRGGIINNGG EEXXTTEERRNNAALL WWOORRKK
       It’s usually much more common that you merge with somebody else than
       merging with your own branches, so it’s worth pointing out that Git
       makes that very easy too, and in fact, it’s not that different from
       doing a _g_i_t _m_e_r_g_e. In fact, a remote merge ends up being nothing more
       than "fetch the work from a remote repository into a temporary tag"
       followed by a _g_i_t _m_e_r_g_e.

       Fetching from a remote repository is done by, unsurprisingly, _g_i_t
       _f_e_t_c_h:

           $ git fetch <remote-repository>

       One of the following transports can be used to name the repository to
       download from:

       SSH
           rreemmoottee..mmaacchhiinnee:://ppaatthh//ttoo//rreeppoo..ggiitt// or

           sssshh::////rreemmoottee..mmaacchhiinnee//ppaatthh//ttoo//rreeppoo..ggiitt//

           This transport can be used for both uploading and downloading, and
           requires you to have a log-in privilege over sssshh to the remote
           machine. It finds out the set of objects the other side lacks by
           exchanging the head commits both ends have and transfers (close to)
           minimum set of objects. It is by far the most efficient way to
           exchange Git objects between repositories.

       Local directory
           //ppaatthh//ttoo//rreeppoo..ggiitt//

           This transport is the same as SSH transport but uses _s_h to run both
           ends on the local machine instead of running other end on the
           remote machine via _s_s_h.

       Git Native
           ggiitt::////rreemmoottee..mmaacchhiinnee//ppaatthh//ttoo//rreeppoo..ggiitt//

           This transport was designed for anonymous downloading. Like SSH
           transport, it finds out the set of objects the downstream side
           lacks and transfers (close to) minimum set of objects.

       HTTP(S)
           hhttttpp::////rreemmoottee..mmaacchhiinnee//ppaatthh//ttoo//rreeppoo..ggiitt//

           Downloader from http and https URL first obtains the topmost commit
           object name from the remote site by looking at the specified
           refname under rreeppoo..ggiitt//rreeffss// directory, and then tries to obtain
           the commit object by downloading from rreeppoo..ggiitt//oobbjjeeccttss//xxxx//xxxxxx......
           using the object name of that commit object. Then it reads the
           commit object to find out its parent commits and the associate tree
           object; it repeats this process until it gets all the necessary
           objects. Because of this behavior, they are sometimes also called
           _c_o_m_m_i_t _w_a_l_k_e_r_s.

           The _c_o_m_m_i_t _w_a_l_k_e_r_s are sometimes also called _d_u_m_b _t_r_a_n_s_p_o_r_t_s,
           because they do not require any Git aware smart server like Git
           Native transport does. Any stock HTTP server that does not even
           support directory index would suffice. But you must prepare your
           repository with _g_i_t _u_p_d_a_t_e_-_s_e_r_v_e_r_-_i_n_f_o to help dumb transport
           downloaders.

       Once you fetch from the remote repository, you mmeerrggee that with your
       current branch.

       However — it’s such a common thing to ffeettcchh and then immediately mmeerrggee,
       that it’s called ggiitt ppuullll, and you can simply do

           $ git pull <remote-repository>

       and optionally give a branch-name for the remote end as a second
       argument.

           NNoottee
           You could do without using any branches at all, by keeping as many
           local repositories as you would like to have branches, and merging
           between them with _g_i_t _p_u_l_l, just like you merge between branches.
           The advantage of this approach is that it lets you keep a set of
           files for each bbrraanncchh checked out and you may find it easier to
           switch back and forth if you juggle multiple lines of development
           simultaneously. Of course, you will pay the price of more disk
           usage to hold multiple working trees, but disk space is cheap these
           days.

       It is likely that you will be pulling from the same remote repository
       from time to time. As a short hand, you can store the remote repository
       URL in the local repository’s config file like this:

           $ git config remote.linus.url http://www.kernel.org/pub/scm/git/git.git/

       and use the "linus" keyword with _g_i_t _p_u_l_l instead of the full URL.

       Examples.

        1. ggiitt ppuullll lliinnuuss

        2. ggiitt ppuullll lliinnuuss ttaagg vv00..9999..11

       the above are equivalent to:

        1. ggiitt ppuullll hhttttpp::////wwwwww..kkeerrnneell..oorrgg//ppuubb//ssccmm//ggiitt//ggiitt..ggiitt// HHEEAADD

        2. ggiitt ppuullll hhttttpp::////wwwwww..kkeerrnneell..oorrgg//ppuubb//ssccmm//ggiitt//ggiitt..ggiitt// ttaagg vv00..9999..11

HHOOWW DDOOEESS TTHHEE MMEERRGGEE WWOORRKK??
       We said this tutorial shows what plumbing does to help you cope with
       the porcelain that isn’t flushing, but we so far did not talk about how
       the merge really works. If you are following this tutorial the first
       time, I’d suggest to skip to "Publishing your work" section and come
       back here later.

       OK, still with me? To give us an example to look at, let’s go back to
       the earlier repository with "hello" and "example" file, and bring
       ourselves back to the pre-merge state:

           $ git show-branch --more=2 master mybranch
           ! [master] Merge work in mybranch
            * [mybranch] Merge work in mybranch
           --
           -- [master] Merge work in mybranch
           +* [master^2] Some work.
           +* [master^] Some fun.

       Remember, before running _g_i_t _m_e_r_g_e, our mmaasstteerr head was at "Some fun."
       commit, while our mmyybbrraanncchh head was at "Some work." commit.

           $ git checkout mybranch
           $ git reset --hard master^2
           $ git checkout master
           $ git reset --hard master^

       After rewinding, the commit structure should look like this:

           $ git show-branch
           * [master] Some fun.
            ! [mybranch] Some work.
           --
           *  [master] Some fun.
            + [mybranch] Some work.
           *+ [master^] Initial commit

       Now we are ready to experiment with the merge by hand.

       ggiitt mmeerrggee command, when merging two branches, uses 3-way merge
       algorithm. First, it finds the common ancestor between them. The
       command it uses is _g_i_t _m_e_r_g_e_-_b_a_s_e:

           $ mb=$(git merge-base HEAD mybranch)

       The command writes the commit object name of the common ancestor to the
       standard output, so we captured its output to a variable, because we
       will be using it in the next step. By the way, the common ancestor
       commit is the "Initial commit" commit in this case. You can tell it by:

           $ git name-rev --name-only --tags $mb
           my-first-tag

       After finding out a common ancestor commit, the second step is this:

           $ git read-tree -m -u $mb HEAD mybranch

       This is the same _g_i_t _r_e_a_d_-_t_r_e_e command we have already seen, but it
       takes three trees, unlike previous examples. This reads the contents of
       each tree into different _s_t_a_g_e in the index file (the first tree goes
       to stage 1, the second to stage 2, etc.). After reading three trees
       into three stages, the paths that are the same in all three stages are
       _c_o_l_l_a_p_s_e_d into stage 0. Also paths that are the same in two of three
       stages are collapsed into stage 0, taking the SHA-1 from either stage 2
       or stage 3, whichever is different from stage 1 (i.e. only one side
       changed from the common ancestor).

       After _c_o_l_l_a_p_s_i_n_g operation, paths that are different in three trees are
       left in non-zero stages. At this point, you can inspect the index file
       with this command:

           $ git ls-files --stage
           100644 7f8b141b65fdcee47321e399a2598a235a032422 0       example
           100644 557db03de997c86a4a028e1ebd3a1ceb225be238 1       hello
           100644 ba42a2a96e3027f3333e13ede4ccf4498c3ae942 2       hello
           100644 cc44c73eb783565da5831b4d820c962954019b69 3       hello

       In our example of only two files, we did not have unchanged files so
       only _e_x_a_m_p_l_e resulted in collapsing. But in real-life large projects,
       when only a small number of files change in one commit, this _c_o_l_l_a_p_s_i_n_g
       tends to trivially merge most of the paths fairly quickly, leaving only
       a handful of real changes in non-zero stages.

       To look at only non-zero stages, use ----uunnmmeerrggeedd flag:

           $ git ls-files --unmerged
           100644 557db03de997c86a4a028e1ebd3a1ceb225be238 1       hello
           100644 ba42a2a96e3027f3333e13ede4ccf4498c3ae942 2       hello
           100644 cc44c73eb783565da5831b4d820c962954019b69 3       hello

       The next step of merging is to merge these three versions of the file,
       using 3-way merge. This is done by giving _g_i_t _m_e_r_g_e_-_o_n_e_-_f_i_l_e command as
       one of the arguments to _g_i_t _m_e_r_g_e_-_i_n_d_e_x command:

           $ git merge-index git-merge-one-file hello
           Auto-merging hello
           ERROR: Merge conflict in hello
           fatal: merge program failed

       _g_i_t _m_e_r_g_e_-_o_n_e_-_f_i_l_e script is called with parameters to describe those
       three versions, and is responsible to leave the merge results in the
       working tree. It is a fairly straightforward shell script, and
       eventually calls _m_e_r_g_e program from RCS suite to perform a file-level
       3-way merge. In this case, _m_e_r_g_e detects conflicts, and the merge
       result with conflict marks is left in the working tree.. This can be
       seen if you run llss--ffiilleess ----ssttaaggee again at this point:

           $ git ls-files --stage
           100644 7f8b141b65fdcee47321e399a2598a235a032422 0       example
           100644 557db03de997c86a4a028e1ebd3a1ceb225be238 1       hello
           100644 ba42a2a96e3027f3333e13ede4ccf4498c3ae942 2       hello
           100644 cc44c73eb783565da5831b4d820c962954019b69 3       hello

       This is the state of the index file and the working file after _g_i_t
       _m_e_r_g_e returns control back to you, leaving the conflicting merge for
       you to resolve. Notice that the path hheelllloo is still unmerged, and what
       you see with _g_i_t _d_i_f_f at this point is differences since stage 2 (i.e.
       your version).

PPUUBBLLIISSHHIINNGG YYOOUURR WWOORRKK
       So, we can use somebody else’s work from a remote repository, but how
       can yyoouu prepare a repository to let other people pull from it?

       You do your real work in your working tree that has your primary
       repository hanging under it as its ..ggiitt subdirectory. You ccoouulldd make
       that repository accessible remotely and ask people to pull from it, but
       in practice that is not the way things are usually done. A recommended
       way is to have a public repository, make it reachable by other people,
       and when the changes you made in your primary working tree are in good
       shape, update the public repository from it. This is often called
       _p_u_s_h_i_n_g.

           NNoottee
           This public repository could further be mirrored, and that is how
           Git repositories at kkeerrnneell..oorrgg are managed.

       Publishing the changes from your local (private) repository to your
       remote (public) repository requires a write privilege on the remote
       machine. You need to have an SSH account there to run a single command,
       _g_i_t_-_r_e_c_e_i_v_e_-_p_a_c_k.

       First, you need to create an empty repository on the remote machine
       that will house your public repository. This empty repository will be
       populated and be kept up-to-date by pushing into it later. Obviously,
       this repository creation needs to be done only once.

           NNoottee
           _g_i_t _p_u_s_h uses a pair of commands, _g_i_t _s_e_n_d_-_p_a_c_k on your local
           machine, and _g_i_t_-_r_e_c_e_i_v_e_-_p_a_c_k on the remote machine. The
           communication between the two over the network internally uses an
           SSH connection.

       Your private repository’s Git directory is usually ..ggiitt, but your
       public repository is often named after the project name, i.e.
       <<pprroojjeecctt>>..ggiitt. Let’s create such a public repository for project
       mmyy--ggiitt. After logging into the remote machine, create an empty
       directory:

           $ mkdir my-git.git

       Then, make that directory into a Git repository by running _g_i_t _i_n_i_t,
       but this time, since its name is not the usual ..ggiitt, we do things
       slightly differently:

           $ GIT_DIR=my-git.git git init

       Make sure this directory is available for others you want your changes
       to be pulled via the transport of your choice. Also you need to make
       sure that you have the _g_i_t_-_r_e_c_e_i_v_e_-_p_a_c_k program on the $$PPAATTHH.

           NNoottee
           Many installations of sshd do not invoke your shell as the login
           shell when you directly run programs; what this means is that if
           your login shell is _b_a_s_h, only ..bbaasshhrrcc is read and not
           ..bbaasshh__pprrooffiillee. As a workaround, make sure ..bbaasshhrrcc sets up $$PPAATTHH so
           that you can run _g_i_t_-_r_e_c_e_i_v_e_-_p_a_c_k program.

           NNoottee
           If you plan to publish this repository to be accessed over http,
           you should do mmvv mmyy--ggiitt..ggiitt//hhooookkss//ppoosstt--uuppddaattee..ssaammppllee
           mmyy--ggiitt..ggiitt//hhooookkss//ppoosstt--uuppddaattee at this point. This makes sure that
           every time you push into this repository, ggiitt uuppddaattee--sseerrvveerr--iinnffoo is
           run.

       Your "public repository" is now ready to accept your changes. Come back
       to the machine you have your private repository. From there, run this
       command:

           $ git push <public-host>:/path/to/my-git.git master

       This synchronizes your public repository to match the named branch head
       (i.e. mmaasstteerr in this case) and objects reachable from them in your
       current repository.

       As a real example, this is how I update my public Git repository.
       Kernel.org mirror network takes care of the propagation to other
       publicly visible machines:

           $ git push master.kernel.org:/pub/scm/git/git.git/

PPAACCKKIINNGG YYOOUURR RREEPPOOSSIITTOORRYY
       Earlier, we saw that one file under ..ggiitt//oobbjjeeccttss//????// directory is
       stored for each Git object you create. This representation is efficient
       to create atomically and safely, but not so convenient to transport
       over the network. Since Git objects are immutable once they are
       created, there is a way to optimize the storage by "packing them
       together". The command

           $ git repack

       will do it for you. If you followed the tutorial examples, you would
       have accumulated about 17 objects in ..ggiitt//oobbjjeeccttss//????// directories by
       now. _g_i_t _r_e_p_a_c_k tells you how many objects it packed, and stores the
       packed file in the ..ggiitt//oobbjjeeccttss//ppaacckk directory.

           NNoottee
           You will see two files, ppaacckk--**..ppaacckk and ppaacckk--**..iiddxx, in
           ..ggiitt//oobbjjeeccttss//ppaacckk directory. They are closely related to each
           other, and if you ever copy them by hand to a different repository
           for whatever reason, you should make sure you copy them together.
           The former holds all the data from the objects in the pack, and the
           latter holds the index for random access.

       If you are paranoid, running _g_i_t _v_e_r_i_f_y_-_p_a_c_k command would detect if
       you have a corrupt pack, but do not worry too much. Our programs are
       always perfect ;-).

       Once you have packed objects, you do not need to leave the unpacked
       objects that are contained in the pack file anymore.

           $ git prune-packed

       would remove them for you.

       You can try running ffiinndd ..ggiitt//oobbjjeeccttss --ttyyppee ff before and after you run
       ggiitt pprruunnee--ppaacckkeedd if you are curious. Also ggiitt ccoouunntt--oobbjjeeccttss would tell
       you how many unpacked objects are in your repository and how much space
       they are consuming.

           NNoottee
           ggiitt ppuullll is slightly cumbersome for HTTP transport, as a packed
           repository may contain relatively few objects in a relatively large
           pack. If you expect many HTTP pulls from your public repository you
           might want to repack & prune often, or never.

       If you run ggiitt rreeppaacckk again at this point, it will say "Nothing new to
       pack.". Once you continue your development and accumulate the changes,
       running ggiitt rreeppaacckk again will create a new pack, that contains objects
       created since you packed your repository the last time. We recommend
       that you pack your project soon after the initial import (unless you
       are starting your project from scratch), and then run ggiitt rreeppaacckk every
       once in a while, depending on how active your project is.

       When a repository is synchronized via ggiitt ppuusshh and ggiitt ppuullll objects
       packed in the source repository are usually stored unpacked in the
       destination. While this allows you to use different packing strategies
       on both ends, it also means you may need to repack both repositories
       every once in a while.

WWOORRKKIINNGG WWIITTHH OOTTHHEERRSS
       Although Git is a truly distributed system, it is often convenient to
       organize your project with an informal hierarchy of developers. Linux
       kernel development is run this way. There is a nice illustration (page
       17, "Merges to Mainline") in RRaannddyy DDuunnllaapp’’ss pprreesseennttaattiioonn[2].

       It should be stressed that this hierarchy is purely iinnffoorrmmaall. There is
       nothing fundamental in Git that enforces the "chain of patch flow" this
       hierarchy implies. You do not have to pull from only one remote
       repository.

       A recommended workflow for a "project lead" goes like this:

        1. Prepare your primary repository on your local machine. Your work is
           done there.

        2. Prepare a public repository accessible to others.

           If other people are pulling from your repository over dumb
           transport protocols (HTTP), you need to keep this repository _d_u_m_b
           _t_r_a_n_s_p_o_r_t _f_r_i_e_n_d_l_y. After ggiitt iinniitt,
           $$GGIITT__DDIIRR//hhooookkss//ppoosstt--uuppddaattee..ssaammppllee copied from the standard
           templates would contain a call to _g_i_t _u_p_d_a_t_e_-_s_e_r_v_e_r_-_i_n_f_o but you
           need to manually enable the hook with mmvv ppoosstt--uuppddaattee..ssaammppllee
           ppoosstt--uuppddaattee. This makes sure _g_i_t _u_p_d_a_t_e_-_s_e_r_v_e_r_-_i_n_f_o keeps the
           necessary files up-to-date.

        3. Push into the public repository from your primary repository.

        4. _g_i_t _r_e_p_a_c_k the public repository. This establishes a big pack that
           contains the initial set of objects as the baseline, and possibly
           _g_i_t _p_r_u_n_e if the transport used for pulling from your repository
           supports packed repositories.

        5. Keep working in your primary repository. Your changes include
           modifications of your own, patches you receive via e-mails, and
           merges resulting from pulling the "public" repositories of your
           "subsystem maintainers".

           You can repack this private repository whenever you feel like.

        6. Push your changes to the public repository, and announce it to the
           public.

        7. Every once in a while, _g_i_t _r_e_p_a_c_k the public repository. Go back to
           step 5. and continue working.

       A recommended work cycle for a "subsystem maintainer" who works on that
       project and has an own "public repository" goes like this:

        1. Prepare your work repository, by running _g_i_t _c_l_o_n_e on the public
           repository of the "project lead". The URL used for the initial
           cloning is stored in the remote.origin.url configuration variable.

        2. Prepare a public repository accessible to others, just like the
           "project lead" person does.

        3. Copy over the packed files from "project lead" public repository to
           your public repository, unless the "project lead" repository lives
           on the same machine as yours. In the latter case, you can use
           oobbjjeeccttss//iinnffoo//aalltteerrnnaatteess file to point at the repository you are
           borrowing from.

        4. Push into the public repository from your primary repository. Run
           _g_i_t _r_e_p_a_c_k, and possibly _g_i_t _p_r_u_n_e if the transport used for
           pulling from your repository supports packed repositories.

        5. Keep working in your primary repository. Your changes include
           modifications of your own, patches you receive via e-mails, and
           merges resulting from pulling the "public" repositories of your
           "project lead" and possibly your "sub-subsystem maintainers".

           You can repack this private repository whenever you feel like.

        6. Push your changes to your public repository, and ask your "project
           lead" and possibly your "sub-subsystem maintainers" to pull from
           it.

        7. Every once in a while, _g_i_t _r_e_p_a_c_k the public repository. Go back to
           step 5. and continue working.

       A recommended work cycle for an "individual developer" who does not
       have a "public" repository is somewhat different. It goes like this:

        1. Prepare your work repository, by _g_i_t _c_l_o_n_e the public repository of
           the "project lead" (or a "subsystem maintainer", if you work on a
           subsystem). The URL used for the initial cloning is stored in the
           remote.origin.url configuration variable.

        2. Do your work in your repository on _m_a_s_t_e_r branch.

        3. Run ggiitt ffeettcchh oorriiggiinn from the public repository of your upstream
           every once in a while. This does only the first half of ggiitt ppuullll
           but does not merge. The head of the public repository is stored in
           ..ggiitt//rreeffss//rreemmootteess//oorriiggiinn//mmaasstteerr.

        4. Use ggiitt cchheerrrryy oorriiggiinn to see which ones of your patches were
           accepted, and/or use ggiitt rreebbaassee oorriiggiinn to port your unmerged
           changes forward to the updated upstream.

        5. Use ggiitt ffoorrmmaatt--ppaattcchh oorriiggiinn to prepare patches for e-mail
           submission to your upstream and send it out. Go back to step 2. and
           continue.

WWOORRKKIINNGG WWIITTHH OOTTHHEERRSS,, SSHHAARREEDD RREEPPOOSSIITTOORRYY SSTTYYLLEE
       If you are coming from a CVS background, the style of cooperation
       suggested in the previous section may be new to you. You do not have to
       worry. Git supports the "shared public repository" style of cooperation
       you are probably more familiar with as well.

       See ggiittccvvss--mmiiggrraattiioonn(7) for the details.

BBUUNNDDLLIINNGG YYOOUURR WWOORRKK TTOOGGEETTHHEERR
       It is likely that you will be working on more than one thing at a time.
       It is easy to manage those more-or-less independent tasks using
       branches with Git.

       We have already seen how branches work previously, with "fun and work"
       example using two branches. The idea is the same if there are more than
       two branches. Let’s say you started out from "master" head, and have
       some new code in the "master" branch, and two independent fixes in the
       "commit-fix" and "diff-fix" branches:

           $ git show-branch
           ! [commit-fix] Fix commit message normalization.
            ! [diff-fix] Fix rename detection.
             * [master] Release candidate #1
           ---
            +  [diff-fix] Fix rename detection.
            +  [diff-fix~1] Better common substring algorithm.
           +   [commit-fix] Fix commit message normalization.
             * [master] Release candidate #1
           ++* [diff-fix~2] Pretty-print messages.

       Both fixes are tested well, and at this point, you want to merge in
       both of them. You could merge in _d_i_f_f_-_f_i_x first and then _c_o_m_m_i_t_-_f_i_x
       next, like this:

           $ git merge -m "Merge fix in diff-fix" diff-fix
           $ git merge -m "Merge fix in commit-fix" commit-fix

       Which would result in:

           $ git show-branch
           ! [commit-fix] Fix commit message normalization.
            ! [diff-fix] Fix rename detection.
             * [master] Merge fix in commit-fix
           ---
             - [master] Merge fix in commit-fix
           + * [commit-fix] Fix commit message normalization.
             - [master~1] Merge fix in diff-fix
            +* [diff-fix] Fix rename detection.
            +* [diff-fix~1] Better common substring algorithm.
             * [master~2] Release candidate #1
           ++* [master~3] Pretty-print messages.

       However, there is no particular reason to merge in one branch first and
       the other next, when what you have are a set of truly independent
       changes (if the order mattered, then they are not independent by
       definition). You could instead merge those two branches into the
       current branch at once. First let’s undo what we just did and start
       over. We would want to get the master branch before these two merges by
       resetting it to _m_a_s_t_e_r_~_2:

           $ git reset --hard master~2

       You can make sure ggiitt sshhooww--bbrraanncchh matches the state before those two
       _g_i_t _m_e_r_g_e you just did. Then, instead of running two _g_i_t _m_e_r_g_e commands
       in a row, you would merge these two branch heads (this is known as
       _m_a_k_i_n_g _a_n _O_c_t_o_p_u_s):

           $ git merge commit-fix diff-fix
           $ git show-branch
           ! [commit-fix] Fix commit message normalization.
            ! [diff-fix] Fix rename detection.
             * [master] Octopus merge of branches 'diff-fix' and 'commit-fix'
           ---
             - [master] Octopus merge of branches 'diff-fix' and 'commit-fix'
           + * [commit-fix] Fix commit message normalization.
            +* [diff-fix] Fix rename detection.
            +* [diff-fix~1] Better common substring algorithm.
             * [master~1] Release candidate #1
           ++* [master~2] Pretty-print messages.

       Note that you should not do Octopus just because you can. An octopus is
       a valid thing to do and often makes it easier to view the commit
       history if you are merging more than two independent changes at the
       same time. However, if you have merge conflicts with any of the
       branches you are merging in and need to hand resolve, that is an
       indication that the development happened in those branches were not
       independent after all, and you should merge two at a time, documenting
       how you resolved the conflicts, and the reason why you preferred
       changes made in one side over the other. Otherwise it would make the
       project history harder to follow, not easier.

SSEEEE AALLSSOO
       ggiittttuuttoorriiaall(7), ggiittttuuttoorriiaall--22(7), ggiittccvvss--mmiiggrraattiioonn(7), ggiitt--hheellpp(1),
       ggiitteevveerryyddaayy(7), TThhee GGiitt UUsseerr’’ss MMaannuuaall[1]

GGIITT
       Part of the ggiitt(1) suite

NNOOTTEESS
        1. the Git User Manual
           git-htmldocs/user-manual.html

        2. Randy Dunlap’s presentation
           https://web.archive.org/web/20120915203609/http://www.xenotime.net/linux/mentor/linux-mentoring-2006.pdf

Git 2.13.6                        09/24/2017               GITCORE-TUTORIAL(7)

git help glossary

GITGLOSSARY(7)                    Git Manual                    GITGLOSSARY(7)

NNAAMMEE
       gitglossary - A Git Glossary

SSYYNNOOPPSSIISS
       *

DDEESSCCRRIIPPTTIIOONN
       alternate object database
           Via the alternates mechanism, a repository can inherit part of its
           object database from another object database, which is called an
           "alternate".

       bare repository
           A bare repository is normally an appropriately named directory with
           a ..ggiitt suffix that does not have a locally checked-out copy of any
           of the files under revision control. That is, all of the Git
           administrative and control files that would normally be present in
           the hidden ..ggiitt sub-directory are directly present in the
           rreeppoossiittoorryy..ggiitt directory instead, and no other files are present
           and checked out. Usually publishers of public repositories make
           bare repositories available.

       blob object
           Untyped object, e.g. the contents of a file.

       branch
           A "branch" is an active line of development. The most recent commit
           on a branch is referred to as the tip of that branch. The tip of
           the branch is referenced by a branch head, which moves forward as
           additional development is done on the branch. A single Git
           repository can track an arbitrary number of branches, but your
           working tree is associated with just one of them (the "current" or
           "checked out" branch), and HEAD points to that branch.

       cache
           Obsolete for: index.

       chain
           A list of objects, where each object in the list contains a
           reference to its successor (for example, the successor of a commit
           could be one of its parents).

       changeset
           BitKeeper/cvsps speak for "commit". Since Git does not store
           changes, but states, it really does not make sense to use the term
           "changesets" with Git.

       checkout
           The action of updating all or part of the working tree with a tree
           object or blob from the object database, and updating the index and
           HEAD if the whole working tree has been pointed at a new branch.

       cherry-picking
           In SCM jargon, "cherry pick" means to choose a subset of changes
           out of a series of changes (typically commits) and record them as a
           new series of changes on top of a different codebase. In Git, this
           is performed by the "git cherry-pick" command to extract the change
           introduced by an existing commit and to record it based on the tip
           of the current branch as a new commit.

       clean
           A working tree is clean, if it corresponds to the revision
           referenced by the current head. Also see "dirty".

       commit
           As a noun: A single point in the Git history; the entire history of
           a project is represented as a set of interrelated commits. The word
           "commit" is often used by Git in the same places other revision
           control systems use the words "revision" or "version". Also used as
           a short hand for commit object.

           As a verb: The action of storing a new snapshot of the project’s
           state in the Git history, by creating a new commit representing the
           current state of the index and advancing HEAD to point at the new
           commit.

       commit object
           An object which contains the information about a particular
           revision, such as parents, committer, author, date and the tree
           object which corresponds to the top directory of the stored
           revision.

       commit-ish (also committish)
           A commit object or an object that can be recursively dereferenced
           to a commit object. The following are all commit-ishes: a commit
           object, a tag object that points to a commit object, a tag object
           that points to a tag object that points to a commit object, etc.

       core Git
           Fundamental data structures and utilities of Git. Exposes only
           limited source code management tools.

       DAG
           Directed acyclic graph. The commit objects form a directed acyclic
           graph, because they have parents (directed), and the graph of
           commit objects is acyclic (there is no chain which begins and ends
           with the same object).

       dangling object
           An unreachable object which is not reachable even from other
           unreachable objects; a dangling object has no references to it from
           any reference or object in the repository.

       detached HEAD
           Normally the HEAD stores the name of a branch, and commands that
           operate on the history HEAD represents operate on the history
           leading to the tip of the branch the HEAD points at. However, Git
           also allows you to check out an arbitrary commit that isn’t
           necessarily the tip of any particular branch. The HEAD in such a
           state is called "detached".

           Note that commands that operate on the history of the current
           branch (e.g.  ggiitt ccoommmmiitt to build a new history on top of it) still
           work while the HEAD is detached. They update the HEAD to point at
           the tip of the updated history without affecting any branch.
           Commands that update or inquire information _a_b_o_u_t the current
           branch (e.g.  ggiitt bbrraanncchh ----sseett--uuppssttrreeaamm--ttoo that sets what
           remote-tracking branch the current branch integrates with)
           obviously do not work, as there is no (real) current branch to ask
           about in this state.

       directory
           The list you get with "ls" :-)

       dirty
           A working tree is said to be "dirty" if it contains modifications
           which have not been committed to the current branch.

       evil merge
           An evil merge is a merge that introduces changes that do not appear
           in any parent.

       fast-forward
           A fast-forward is a special type of merge where you have a revision
           and you are "merging" another branch's changes that happen to be a
           descendant of what you have. In such a case, you do not make a new
           mergecommit but instead just update to his revision. This will
           happen frequently on a remote-tracking branch of a remote
           repository.

       fetch
           Fetching a branch means to get the branch’s head ref from a remote
           repository, to find out which objects are missing from the local
           object database, and to get them, too. See also ggiitt--ffeettcchh(1).

       file system
           Linus Torvalds originally designed Git to be a user space file
           system, i.e. the infrastructure to hold files and directories. That
           ensured the efficiency and speed of Git.

       Git archive
           Synonym for repository (for arch people).

       gitfile
           A plain file ..ggiitt at the root of a working tree that points at the
           directory that is the real repository.

       grafts
           Grafts enables two otherwise different lines of development to be
           joined together by recording fake ancestry information for commits.
           This way you can make Git pretend the set of parents a commit has
           is different from what was recorded when the commit was created.
           Configured via the ..ggiitt//iinnffoo//ggrraaffttss file.

           Note that the grafts mechanism is outdated and can lead to problems
           transferring objects between repositories; see ggiitt--rreeppllaaccee(1) for a
           more flexible and robust system to do the same thing.

       hash
           In Git’s context, synonym for object name.

       head
           A named reference to the commit at the tip of a branch. Heads are
           stored in a file in $$GGIITT__DDIIRR//rreeffss//hheeaaddss// directory, except when
           using packed refs. (See ggiitt--ppaacckk--rreeffss(1).)

       HEAD
           The current branch. In more detail: Your working tree is normally
           derived from the state of the tree referred to by HEAD. HEAD is a
           reference to one of the heads in your repository, except when using
           a detached HEAD, in which case it directly references an arbitrary
           commit.

       head ref
           A synonym for head.

       hook
           During the normal execution of several Git commands, call-outs are
           made to optional scripts that allow a developer to add
           functionality or checking. Typically, the hooks allow for a command
           to be pre-verified and potentially aborted, and allow for a
           post-notification after the operation is done. The hook scripts are
           found in the $$GGIITT__DDIIRR//hhooookkss// directory, and are enabled by simply
           removing the ..ssaammppllee suffix from the filename. In earlier versions
           of Git you had to make them executable.

       index
           A collection of files with stat information, whose contents are
           stored as objects. The index is a stored version of your working
           tree. Truth be told, it can also contain a second, and even a third
           version of a working tree, which are used when merging.

       index entry
           The information regarding a particular file, stored in the index.
           An index entry can be unmerged, if a merge was started, but not yet
           finished (i.e. if the index contains multiple versions of that
           file).

       master
           The default development branch. Whenever you create a Git
           repository, a branch named "master" is created, and becomes the
           active branch. In most cases, this contains the local development,
           though that is purely by convention and is not required.

       merge
           As a verb: To bring the contents of another branch (possibly from
           an external repository) into the current branch. In the case where
           the merged-in branch is from a different repository, this is done
           by first fetching the remote branch and then merging the result
           into the current branch. This combination of fetch and merge
           operations is called a pull. Merging is performed by an automatic
           process that identifies changes made since the branches diverged,
           and then applies all those changes together. In cases where changes
           conflict, manual intervention may be required to complete the
           merge.

           As a noun: unless it is a fast-forward, a successful merge results
           in the creation of a new commit representing the result of the
           merge, and having as parents the tips of the merged branches. This
           commit is referred to as a "merge commit", or sometimes just a
           "merge".

       object
           The unit of storage in Git. It is uniquely identified by the SHA-1
           of its contents. Consequently, an object can not be changed.

       object database
           Stores a set of "objects", and an individual object is identified
           by its object name. The objects usually live in $$GGIITT__DDIIRR//oobbjjeeccttss//.

       object identifier
           Synonym for object name.

       object name
           The unique identifier of an object. The object name is usually
           represented by a 40 character hexadecimal string. Also colloquially
           called SHA-1.

       object type
           One of the identifiers "commit", "tree", "tag" or "blob" describing
           the type of an object.

       octopus
           To merge more than two branches.

       origin
           The default upstream repository. Most projects have at least one
           upstream project which they track. By default _o_r_i_g_i_n is used for
           that purpose. New upstream updates will be fetched into remote-
           tracking branches named origin/name-of-upstream-branch, which you
           can see using ggiitt bbrraanncchh --rr.

       pack
           A set of objects which have been compressed into one file (to save
           space or to transmit them efficiently).

       pack index
           The list of identifiers, and other information, of the objects in a
           pack, to assist in efficiently accessing the contents of a pack.

       pathspec
           Pattern used to limit paths in Git commands.

           Pathspecs are used on the command line of "git ls-files", "git
           ls-tree", "git add", "git grep", "git diff", "git checkout", and
           many other commands to limit the scope of operations to some subset
           of the tree or worktree. See the documentation of each command for
           whether paths are relative to the current directory or toplevel.
           The pathspec syntax is as follows:

           ·   any path matches itself

           ·   the pathspec up to the last slash represents a directory
               prefix. The scope of that pathspec is limited to that subtree.

           ·   the rest of the pathspec is a pattern for the remainder of the
               pathname. Paths relative to the directory prefix will be
               matched against that pattern using fnmatch(3); in particular, _*
               and _?_c_a_n match directory separators.

           For example, Documentation/*.jpg will match all .jpg files in the
           Documentation subtree, including
           Documentation/chapter_1/figure_1.jpg.

           A pathspec that begins with a colon :: has special meaning. In the
           short form, the leading colon :: is followed by zero or more "magic
           signature" letters (which optionally is terminated by another colon
           ::), and the remainder is the pattern to match against the path. The
           "magic signature" consists of ASCII symbols that are neither
           alphanumeric, glob, regex special characters nor colon. The
           optional colon that terminates the "magic signature" can be omitted
           if the pattern begins with a character that does not belong to
           "magic signature" symbol set and is not a colon.

           In the long form, the leading colon :: is followed by a open
           parenthesis ((, a comma-separated list of zero or more "magic
           words", and a close parentheses )), and the remainder is the pattern
           to match against the path.

           A pathspec with only a colon means "there is no pathspec". This
           form should not be combined with other pathspec.

           top
               The magic word ttoopp (magic signature: //) makes the pattern match
               from the root of the working tree, even when you are running
               the command from inside a subdirectory.

           literal
               Wildcards in the pattern such as ** or ??  are treated as literal
               characters.

           icase
               Case insensitive match.

           glob
               Git treats the pattern as a shell glob suitable for consumption
               by fnmatch(3) with the FNM_PATHNAME flag: wildcards in the
               pattern will not match a / in the pathname. For example,
               "Documentation/*.html" matches "Documentation/git.html" but not
               "Documentation/ppc/ppc.html" or
               "tools/perf/Documentation/perf.html".

               Two consecutive asterisks ("****") in patterns matched against
               full pathname may have special meaning:

               ·   A leading "****" followed by a slash means match in all
                   directories. For example, "****//ffoooo" matches file or
                   directory "ffoooo" anywhere, the same as pattern "ffoooo".
                   "****//ffoooo//bbaarr" matches file or directory "bbaarr" anywhere that
                   is directly under directory "ffoooo".

               ·   A trailing "//****" matches everything inside. For example,
                   "aabbcc//****" matches all files inside directory "abc", relative
                   to the location of the ..ggiittiiggnnoorree file, with infinite
                   depth.

               ·   A slash followed by two consecutive asterisks then a slash
                   matches zero or more directories. For example, "aa//****//bb"
                   matches "aa//bb", "aa//xx//bb", "aa//xx//yy//bb" and so on.

               ·   Other consecutive asterisks are considered invalid.

                   Glob magic is incompatible with literal magic.

           attr
               After aattttrr:: comes a space separated list of "attribute
               requirements", all of which must be met in order for the path
               to be considered a match; this is in addition to the usual
               non-magic pathspec pattern matching. See ggiittaattttrriibbuutteess(5).

               Each of the attribute requirements for the path takes one of
               these forms:

               ·   "AATTTTRR" requires that the attribute AATTTTRR be set.

               ·   "--AATTTTRR" requires that the attribute AATTTTRR be unset.

               ·   "AATTTTRR==VVAALLUUEE" requires that the attribute AATTTTRR be set to the
                   string VVAALLUUEE.

               ·   "!!AATTTTRR" requires that the attribute AATTTTRR be unspecified.

           exclude
               After a path matches any non-exclude pathspec, it will be run
               through all exclude pathspec (magic signature: !!  or its
               synonym ^^). If it matches, the path is ignored. When there is
               no non-exclude pathspec, the exclusion is applied to the result
               set as if invoked without any pathspec.

       parent
           A commit object contains a (possibly empty) list of the logical
           predecessor(s) in the line of development, i.e. its parents.

       pickaxe
           The term pickaxe refers to an option to the diffcore routines that
           help select changes that add or delete a given text string. With
           the ----ppiicckkaaxxee--aallll option, it can be used to view the full changeset
           that introduced or removed, say, a particular line of text. See
           ggiitt--ddiiffff(1).

       plumbing
           Cute name for core Git.

       porcelain
           Cute name for programs and program suites depending on core Git,
           presenting a high level access to core Git. Porcelains expose more
           of a SCM interface than the plumbing.

       per-worktree ref
           Refs that are per-worktree, rather than global. This is presently
           only HEAD and any refs that start with rreeffss//bbiisseecctt//, but might
           later include other unusual refs.

       pseudoref
           Pseudorefs are a class of files under $$GGIITT__DDIIRR which behave like
           refs for the purposes of rev-parse, but which are treated specially
           by git. Pseudorefs both have names that are all-caps, and always
           start with a line consisting of a SHA-1 followed by whitespace. So,
           HEAD is not a pseudoref, because it is sometimes a symbolic ref.
           They might optionally contain some additional data.  MMEERRGGEE__HHEEAADD and
           CCHHEERRRRYY__PPIICCKK__HHEEAADD are examples. Unlike per-worktree refs, these
           files cannot be symbolic refs, and never have reflogs. They also
           cannot be updated through the normal ref update machinery. Instead,
           they are updated by directly writing to the files. However, they
           can be read as if they were refs, so ggiitt rreevv--ppaarrssee MMEERRGGEE__HHEEAADD will
           work.

       pull
           Pulling a branch means to fetch it and merge it. See also ggiitt--
           ppuullll(1).

       push
           Pushing a branch means to get the branch’s head ref from a remote
           repository, find out if it is a direct ancestor to the branch’s
           local head ref, and in that case, putting all objects, which are
           reachable from the local head ref, and which are missing from the
           remote repository, into the remote object database, and updating
           the remote head ref. If the remote head is not an ancestor to the
           local head, the push fails.

       reachable
           All of the ancestors of a given commit are said to be "reachable"
           from that commit. More generally, one object is reachable from
           another if we can reach the one from the other by a chain that
           follows tags to whatever they tag, commits to their parents or
           trees, and trees to the trees or blobs that they contain.

       rebase
           To reapply a series of changes from a branch to a different base,
           and reset the head of that branch to the result.

       ref
           A name that begins with rreeffss// (e.g.  rreeffss//hheeaaddss//mmaasstteerr) that points
           to an object name or another ref (the latter is called a symbolic
           ref). For convenience, a ref can sometimes be abbreviated when used
           as an argument to a Git command; see ggiittrreevviissiioonnss(7) for details.
           Refs are stored in the repository.

           The ref namespace is hierarchical. Different subhierarchies are
           used for different purposes (e.g. the rreeffss//hheeaaddss// hierarchy is used
           to represent local branches).

           There are a few special-purpose refs that do not begin with rreeffss//.
           The most notable example is HHEEAADD.

       reflog
           A reflog shows the local "history" of a ref. In other words, it can
           tell you what the 3rd last revision in _t_h_i_s repository was, and
           what was the current state in _t_h_i_s repository, yesterday 9:14pm.
           See ggiitt--rreefflloogg(1) for details.

       refspec
           A "refspec" is used by fetch and push to describe the mapping
           between remote ref and local ref.

       remote repository
           A repository which is used to track the same project but resides
           somewhere else. To communicate with remotes, see fetch or push.

       remote-tracking branch
           A ref that is used to follow changes from another repository. It
           typically looks like _r_e_f_s_/_r_e_m_o_t_e_s_/_f_o_o_/_b_a_r (indicating that it
           tracks a branch named _b_a_r in a remote named _f_o_o), and matches the
           right-hand-side of a configured fetch refspec. A remote-tracking
           branch should not contain direct modifications or have local
           commits made to it.

       repository
           A collection of refs together with an object database containing
           all objects which are reachable from the refs, possibly accompanied
           by meta data from one or more porcelains. A repository can share an
           object database with other repositories via alternates mechanism.

       resolve
           The action of fixing up manually what a failed automatic merge left
           behind.

       revision
           Synonym for commit (the noun).

       rewind
           To throw away part of the development, i.e. to assign the head to
           an earlier revision.

       SCM
           Source code management (tool).

       SHA-1
           "Secure Hash Algorithm 1"; a cryptographic hash function. In the
           context of Git used as a synonym for object name.

       shallow clone
           Mostly a synonym to shallow repository but the phrase makes it more
           explicit that it was created by running ggiitt cclloonnee ----ddeepptthh==......
           command.

       shallow repository
           A shallow repository has an incomplete history some of whose
           commits have parents cauterized away (in other words, Git is told
           to pretend that these commits do not have the parents, even though
           they are recorded in the commit object). This is sometimes useful
           when you are interested only in the recent history of a project
           even though the real history recorded in the upstream is much
           larger. A shallow repository is created by giving the ----ddeepptthh
           option to ggiitt--cclloonnee(1), and its history can be later deepened with
           ggiitt--ffeettcchh(1).

       submodule
           A repository that holds the history of a separate project inside
           another repository (the latter of which is called superproject).

       superproject
           A repository that references repositories of other projects in its
           working tree as submodules. The superproject knows about the names
           of (but does not hold copies of) commit objects of the contained
           submodules.

       symref
           Symbolic reference: instead of containing the SHA-1 id itself, it
           is of the format _r_e_f_: _r_e_f_s_/_s_o_m_e_/_t_h_i_n_g and when referenced, it
           recursively dereferences to this reference.  _H_E_A_D is a prime
           example of a symref. Symbolic references are manipulated with the
           ggiitt--ssyymmbboolliicc--rreeff(1) command.

       tag
           A ref under rreeffss//ttaaggss// namespace that points to an object of an
           arbitrary type (typically a tag points to either a tag or a commit
           object). In contrast to a head, a tag is not updated by the ccoommmmiitt
           command. A Git tag has nothing to do with a Lisp tag (which would
           be called an object type in Git’s context). A tag is most typically
           used to mark a particular point in the commit ancestry chain.

       tag object
           An object containing a ref pointing to another object, which can
           contain a message just like a commit object. It can also contain a
           (PGP) signature, in which case it is called a "signed tag object".

       topic branch
           A regular Git branch that is used by a developer to identify a
           conceptual line of development. Since branches are very easy and
           inexpensive, it is often desirable to have several small branches
           that each contain very well defined concepts or small incremental
           yet related changes.

       tree
           Either a working tree, or a tree object together with the dependent
           blob and tree objects (i.e. a stored representation of a working
           tree).

       tree object
           An object containing a list of file names and modes along with refs
           to the associated blob and/or tree objects. A tree is equivalent to
           a directory.

       tree-ish (also treeish)
           A tree object or an object that can be recursively dereferenced to
           a tree object. Dereferencing a commit object yields the tree object
           corresponding to the revision's top directory. The following are
           all tree-ishes: a commit-ish, a tree object, a tag object that
           points to a tree object, a tag object that points to a tag object
           that points to a tree object, etc.

       unmerged index
           An index which contains unmerged index entries.

       unreachable object
           An object which is not reachable from a branch, tag, or any other
           reference.

       upstream branch
           The default branch that is merged into the branch in question (or
           the branch in question is rebased onto). It is configured via
           branch.<name>.remote and branch.<name>.merge. If the upstream
           branch of _A is _o_r_i_g_i_n_/_B sometimes we say "_A is tracking _o_r_i_g_i_n_/_B".

       working tree
           The tree of actual checked out files. The working tree normally
           contains the contents of the HEAD commit’s tree, plus any local
           changes that you have made but not yet committed.

SSEEEE AALLSSOO
       ggiittttuuttoorriiaall(7), ggiittttuuttoorriiaall--22(7), ggiittccvvss--mmiiggrraattiioonn(7), ggiitteevveerryyddaayy(7),
       TThhee GGiitt UUsseerr’’ss MMaannuuaall[1]

GGIITT
       Part of the ggiitt(1) suite

NNOOTTEESS
        1. The Git User’s Manual
           git-htmldocs/user-manual.html

Git 2.13.6                        09/24/2017                    GITGLOSSARY(7)