Documentation / git.txton commit protocol: introduce protocol extension mechanisms (373d70e)
   1git(1)
   2======
   3
   4NAME
   5----
   6git - the stupid content tracker
   7
   8
   9SYNOPSIS
  10--------
  11[verse]
  12'git' [--version] [--help] [-C <path>] [-c <name>=<value>]
  13    [--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]
  14    [-p|--paginate|--no-pager] [--no-replace-objects] [--bare]
  15    [--git-dir=<path>] [--work-tree=<path>] [--namespace=<name>]
  16    [--super-prefix=<path>]
  17    <command> [<args>]
  18
  19DESCRIPTION
  20-----------
  21Git is a fast, scalable, distributed revision control system with an
  22unusually rich command set that provides both high-level operations
  23and full access to internals.
  24
  25See linkgit:gittutorial[7] to get started, then see
  26linkgit:giteveryday[7] for a useful minimum set of
  27commands.  The link:user-manual.html[Git User's Manual] has a more
  28in-depth introduction.
  29
  30After you mastered the basic concepts, you can come back to this
  31page to learn what commands Git offers.  You can learn more about
  32individual Git commands with "git help command".  linkgit:gitcli[7]
  33manual page gives you an overview of the command-line command syntax.
  34
  35A formatted and hyperlinked copy of the latest Git documentation
  36can be viewed at `https://git.github.io/htmldocs/git.html`.
  37
  38
  39OPTIONS
  40-------
  41--version::
  42        Prints the Git suite version that the 'git' program came from.
  43
  44--help::
  45        Prints the synopsis and a list of the most commonly used
  46        commands. If the option `--all` or `-a` is given then all
  47        available commands are printed. If a Git command is named this
  48        option will bring up the manual page for that command.
  49+
  50Other options are available to control how the manual page is
  51displayed. See linkgit:git-help[1] for more information,
  52because `git --help ...` is converted internally into `git
  53help ...`.
  54
  55-C <path>::
  56        Run as if git was started in '<path>' instead of the current working
  57        directory.  When multiple `-C` options are given, each subsequent
  58        non-absolute `-C <path>` is interpreted relative to the preceding `-C
  59        <path>`.
  60+
  61This option affects options that expect path name like `--git-dir` and
  62`--work-tree` in that their interpretations of the path names would be
  63made relative to the working directory caused by the `-C` option. For
  64example the following invocations are equivalent:
  65
  66    git --git-dir=a.git --work-tree=b -C c status
  67    git --git-dir=c/a.git --work-tree=c/b status
  68
  69-c <name>=<value>::
  70        Pass a configuration parameter to the command. The value
  71        given will override values from configuration files.
  72        The <name> is expected in the same format as listed by
  73        'git config' (subkeys separated by dots).
  74+
  75Note that omitting the `=` in `git -c foo.bar ...` is allowed and sets
  76`foo.bar` to the boolean true value (just like `[foo]bar` would in a
  77config file). Including the equals but with an empty value (like `git -c
  78foo.bar= ...`) sets `foo.bar` to the empty string which ` git config
  79--bool` will convert to `false`.
  80
  81--exec-path[=<path>]::
  82        Path to wherever your core Git programs are installed.
  83        This can also be controlled by setting the GIT_EXEC_PATH
  84        environment variable. If no path is given, 'git' will print
  85        the current setting and then exit.
  86
  87--html-path::
  88        Print the path, without trailing slash, where Git's HTML
  89        documentation is installed and exit.
  90
  91--man-path::
  92        Print the manpath (see `man(1)`) for the man pages for
  93        this version of Git and exit.
  94
  95--info-path::
  96        Print the path where the Info files documenting this
  97        version of Git are installed and exit.
  98
  99-p::
 100--paginate::
 101        Pipe all output into 'less' (or if set, $PAGER) if standard
 102        output is a terminal.  This overrides the `pager.<cmd>`
 103        configuration options (see the "Configuration Mechanism" section
 104        below).
 105
 106--no-pager::
 107        Do not pipe Git output into a pager.
 108
 109--git-dir=<path>::
 110        Set the path to the repository. This can also be controlled by
 111        setting the `GIT_DIR` environment variable. It can be an absolute
 112        path or relative path to current working directory.
 113
 114--work-tree=<path>::
 115        Set the path to the working tree. It can be an absolute path
 116        or a path relative to the current working directory.
 117        This can also be controlled by setting the GIT_WORK_TREE
 118        environment variable and the core.worktree configuration
 119        variable (see core.worktree in linkgit:git-config[1] for a
 120        more detailed discussion).
 121
 122--namespace=<path>::
 123        Set the Git namespace.  See linkgit:gitnamespaces[7] for more
 124        details.  Equivalent to setting the `GIT_NAMESPACE` environment
 125        variable.
 126
 127--super-prefix=<path>::
 128        Currently for internal use only.  Set a prefix which gives a path from
 129        above a repository down to its root.  One use is to give submodules
 130        context about the superproject that invoked it.
 131
 132--bare::
 133        Treat the repository as a bare repository.  If GIT_DIR
 134        environment is not set, it is set to the current working
 135        directory.
 136
 137--no-replace-objects::
 138        Do not use replacement refs to replace Git objects. See
 139        linkgit:git-replace[1] for more information.
 140
 141--literal-pathspecs::
 142        Treat pathspecs literally (i.e. no globbing, no pathspec magic).
 143        This is equivalent to setting the `GIT_LITERAL_PATHSPECS` environment
 144        variable to `1`.
 145
 146--glob-pathspecs::
 147        Add "glob" magic to all pathspec. This is equivalent to setting
 148        the `GIT_GLOB_PATHSPECS` environment variable to `1`. Disabling
 149        globbing on individual pathspecs can be done using pathspec
 150        magic ":(literal)"
 151
 152--noglob-pathspecs::
 153        Add "literal" magic to all pathspec. This is equivalent to setting
 154        the `GIT_NOGLOB_PATHSPECS` environment variable to `1`. Enabling
 155        globbing on individual pathspecs can be done using pathspec
 156        magic ":(glob)"
 157
 158--icase-pathspecs::
 159        Add "icase" magic to all pathspec. This is equivalent to setting
 160        the `GIT_ICASE_PATHSPECS` environment variable to `1`.
 161
 162GIT COMMANDS
 163------------
 164
 165We divide Git into high level ("porcelain") commands and low level
 166("plumbing") commands.
 167
 168High-level commands (porcelain)
 169-------------------------------
 170
 171We separate the porcelain commands into the main commands and some
 172ancillary user utilities.
 173
 174Main porcelain commands
 175~~~~~~~~~~~~~~~~~~~~~~~
 176
 177include::cmds-mainporcelain.txt[]
 178
 179Ancillary Commands
 180~~~~~~~~~~~~~~~~~~
 181Manipulators:
 182
 183include::cmds-ancillarymanipulators.txt[]
 184
 185Interrogators:
 186
 187include::cmds-ancillaryinterrogators.txt[]
 188
 189
 190Interacting with Others
 191~~~~~~~~~~~~~~~~~~~~~~~
 192
 193These commands are to interact with foreign SCM and with other
 194people via patch over e-mail.
 195
 196include::cmds-foreignscminterface.txt[]
 197
 198
 199Low-level commands (plumbing)
 200-----------------------------
 201
 202Although Git includes its
 203own porcelain layer, its low-level commands are sufficient to support
 204development of alternative porcelains.  Developers of such porcelains
 205might start by reading about linkgit:git-update-index[1] and
 206linkgit:git-read-tree[1].
 207
 208The interface (input, output, set of options and the semantics)
 209to these low-level commands are meant to be a lot more stable
 210than Porcelain level commands, because these commands are
 211primarily for scripted use.  The interface to Porcelain commands
 212on the other hand are subject to change in order to improve the
 213end user experience.
 214
 215The following description divides
 216the low-level commands into commands that manipulate objects (in
 217the repository, index, and working tree), commands that interrogate and
 218compare objects, and commands that move objects and references between
 219repositories.
 220
 221
 222Manipulation commands
 223~~~~~~~~~~~~~~~~~~~~~
 224
 225include::cmds-plumbingmanipulators.txt[]
 226
 227
 228Interrogation commands
 229~~~~~~~~~~~~~~~~~~~~~~
 230
 231include::cmds-plumbinginterrogators.txt[]
 232
 233In general, the interrogate commands do not touch the files in
 234the working tree.
 235
 236
 237Synching repositories
 238~~~~~~~~~~~~~~~~~~~~~
 239
 240include::cmds-synchingrepositories.txt[]
 241
 242The following are helper commands used by the above; end users
 243typically do not use them directly.
 244
 245include::cmds-synchelpers.txt[]
 246
 247
 248Internal helper commands
 249~~~~~~~~~~~~~~~~~~~~~~~~
 250
 251These are internal helper commands used by other commands; end
 252users typically do not use them directly.
 253
 254include::cmds-purehelpers.txt[]
 255
 256
 257Configuration Mechanism
 258-----------------------
 259
 260Git uses a simple text format to store customizations that are per
 261repository and are per user.  Such a configuration file may look
 262like this:
 263
 264------------
 265#
 266# A '#' or ';' character indicates a comment.
 267#
 268
 269; core variables
 270[core]
 271        ; Don't trust file modes
 272        filemode = false
 273
 274; user identity
 275[user]
 276        name = "Junio C Hamano"
 277        email = "gitster@pobox.com"
 278
 279------------
 280
 281Various commands read from the configuration file and adjust
 282their operation accordingly.  See linkgit:git-config[1] for a
 283list and more details about the configuration mechanism.
 284
 285
 286Identifier Terminology
 287----------------------
 288<object>::
 289        Indicates the object name for any type of object.
 290
 291<blob>::
 292        Indicates a blob object name.
 293
 294<tree>::
 295        Indicates a tree object name.
 296
 297<commit>::
 298        Indicates a commit object name.
 299
 300<tree-ish>::
 301        Indicates a tree, commit or tag object name.  A
 302        command that takes a <tree-ish> argument ultimately wants to
 303        operate on a <tree> object but automatically dereferences
 304        <commit> and <tag> objects that point at a <tree>.
 305
 306<commit-ish>::
 307        Indicates a commit or tag object name.  A
 308        command that takes a <commit-ish> argument ultimately wants to
 309        operate on a <commit> object but automatically dereferences
 310        <tag> objects that point at a <commit>.
 311
 312<type>::
 313        Indicates that an object type is required.
 314        Currently one of: `blob`, `tree`, `commit`, or `tag`.
 315
 316<file>::
 317        Indicates a filename - almost always relative to the
 318        root of the tree structure `GIT_INDEX_FILE` describes.
 319
 320Symbolic Identifiers
 321--------------------
 322Any Git command accepting any <object> can also use the following
 323symbolic notation:
 324
 325HEAD::
 326        indicates the head of the current branch.
 327
 328<tag>::
 329        a valid tag 'name'
 330        (i.e. a `refs/tags/<tag>` reference).
 331
 332<head>::
 333        a valid head 'name'
 334        (i.e. a `refs/heads/<head>` reference).
 335
 336For a more complete list of ways to spell object names, see
 337"SPECIFYING REVISIONS" section in linkgit:gitrevisions[7].
 338
 339
 340File/Directory Structure
 341------------------------
 342
 343Please see the linkgit:gitrepository-layout[5] document.
 344
 345Read linkgit:githooks[5] for more details about each hook.
 346
 347Higher level SCMs may provide and manage additional information in the
 348`$GIT_DIR`.
 349
 350
 351Terminology
 352-----------
 353Please see linkgit:gitglossary[7].
 354
 355
 356Environment Variables
 357---------------------
 358Various Git commands use the following environment variables:
 359
 360The Git Repository
 361~~~~~~~~~~~~~~~~~~
 362These environment variables apply to 'all' core Git commands. Nb: it
 363is worth noting that they may be used/overridden by SCMS sitting above
 364Git so take care if using a foreign front-end.
 365
 366`GIT_INDEX_FILE`::
 367        This environment allows the specification of an alternate
 368        index file. If not specified, the default of `$GIT_DIR/index`
 369        is used.
 370
 371`GIT_INDEX_VERSION`::
 372        This environment variable allows the specification of an index
 373        version for new repositories.  It won't affect existing index
 374        files.  By default index file version 2 or 3 is used. See
 375        linkgit:git-update-index[1] for more information.
 376
 377`GIT_OBJECT_DIRECTORY`::
 378        If the object storage directory is specified via this
 379        environment variable then the sha1 directories are created
 380        underneath - otherwise the default `$GIT_DIR/objects`
 381        directory is used.
 382
 383`GIT_ALTERNATE_OBJECT_DIRECTORIES`::
 384        Due to the immutable nature of Git objects, old objects can be
 385        archived into shared, read-only directories. This variable
 386        specifies a ":" separated (on Windows ";" separated) list
 387        of Git object directories which can be used to search for Git
 388        objects. New objects will not be written to these directories.
 389+
 390        Entries that begin with `"` (double-quote) will be interpreted
 391        as C-style quoted paths, removing leading and trailing
 392        double-quotes and respecting backslash escapes. E.g., the value
 393        `"path-with-\"-and-:-in-it":vanilla-path` has two paths:
 394        `path-with-"-and-:-in-it` and `vanilla-path`.
 395
 396`GIT_DIR`::
 397        If the `GIT_DIR` environment variable is set then it
 398        specifies a path to use instead of the default `.git`
 399        for the base of the repository.
 400        The `--git-dir` command-line option also sets this value.
 401
 402`GIT_WORK_TREE`::
 403        Set the path to the root of the working tree.
 404        This can also be controlled by the `--work-tree` command-line
 405        option and the core.worktree configuration variable.
 406
 407`GIT_NAMESPACE`::
 408        Set the Git namespace; see linkgit:gitnamespaces[7] for details.
 409        The `--namespace` command-line option also sets this value.
 410
 411`GIT_CEILING_DIRECTORIES`::
 412        This should be a colon-separated list of absolute paths.  If
 413        set, it is a list of directories that Git should not chdir up
 414        into while looking for a repository directory (useful for
 415        excluding slow-loading network directories).  It will not
 416        exclude the current working directory or a GIT_DIR set on the
 417        command line or in the environment.  Normally, Git has to read
 418        the entries in this list and resolve any symlink that
 419        might be present in order to compare them with the current
 420        directory.  However, if even this access is slow, you
 421        can add an empty entry to the list to tell Git that the
 422        subsequent entries are not symlinks and needn't be resolved;
 423        e.g.,
 424        `GIT_CEILING_DIRECTORIES=/maybe/symlink::/very/slow/non/symlink`.
 425
 426`GIT_DISCOVERY_ACROSS_FILESYSTEM`::
 427        When run in a directory that does not have ".git" repository
 428        directory, Git tries to find such a directory in the parent
 429        directories to find the top of the working tree, but by default it
 430        does not cross filesystem boundaries.  This environment variable
 431        can be set to true to tell Git not to stop at filesystem
 432        boundaries.  Like `GIT_CEILING_DIRECTORIES`, this will not affect
 433        an explicit repository directory set via `GIT_DIR` or on the
 434        command line.
 435
 436`GIT_COMMON_DIR`::
 437        If this variable is set to a path, non-worktree files that are
 438        normally in $GIT_DIR will be taken from this path
 439        instead. Worktree-specific files such as HEAD or index are
 440        taken from $GIT_DIR. See linkgit:gitrepository-layout[5] and
 441        linkgit:git-worktree[1] for
 442        details. This variable has lower precedence than other path
 443        variables such as GIT_INDEX_FILE, GIT_OBJECT_DIRECTORY...
 444
 445Git Commits
 446~~~~~~~~~~~
 447`GIT_AUTHOR_NAME`::
 448`GIT_AUTHOR_EMAIL`::
 449`GIT_AUTHOR_DATE`::
 450`GIT_COMMITTER_NAME`::
 451`GIT_COMMITTER_EMAIL`::
 452`GIT_COMMITTER_DATE`::
 453'EMAIL'::
 454        see linkgit:git-commit-tree[1]
 455
 456Git Diffs
 457~~~~~~~~~
 458`GIT_DIFF_OPTS`::
 459        Only valid setting is "--unified=??" or "-u??" to set the
 460        number of context lines shown when a unified diff is created.
 461        This takes precedence over any "-U" or "--unified" option
 462        value passed on the Git diff command line.
 463
 464`GIT_EXTERNAL_DIFF`::
 465        When the environment variable `GIT_EXTERNAL_DIFF` is set, the
 466        program named by it is called, instead of the diff invocation
 467        described above.  For a path that is added, removed, or modified,
 468        `GIT_EXTERNAL_DIFF` is called with 7 parameters:
 469
 470        path old-file old-hex old-mode new-file new-hex new-mode
 471+
 472where:
 473
 474        <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the
 475                         contents of <old|new>,
 476        <old|new>-hex:: are the 40-hexdigit SHA-1 hashes,
 477        <old|new>-mode:: are the octal representation of the file modes.
 478+
 479The file parameters can point at the user's working file
 480(e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
 481when a new file is added), or a temporary file (e.g. `old-file` in the
 482index).  `GIT_EXTERNAL_DIFF` should not worry about unlinking the
 483temporary file --- it is removed when `GIT_EXTERNAL_DIFF` exits.
 484+
 485For a path that is unmerged, `GIT_EXTERNAL_DIFF` is called with 1
 486parameter, <path>.
 487+
 488For each path `GIT_EXTERNAL_DIFF` is called, two environment variables,
 489`GIT_DIFF_PATH_COUNTER` and `GIT_DIFF_PATH_TOTAL` are set.
 490
 491`GIT_DIFF_PATH_COUNTER`::
 492        A 1-based counter incremented by one for every path.
 493
 494`GIT_DIFF_PATH_TOTAL`::
 495        The total number of paths.
 496
 497other
 498~~~~~
 499`GIT_MERGE_VERBOSITY`::
 500        A number controlling the amount of output shown by
 501        the recursive merge strategy.  Overrides merge.verbosity.
 502        See linkgit:git-merge[1]
 503
 504`GIT_PAGER`::
 505        This environment variable overrides `$PAGER`. If it is set
 506        to an empty string or to the value "cat", Git will not launch
 507        a pager.  See also the `core.pager` option in
 508        linkgit:git-config[1].
 509
 510`GIT_EDITOR`::
 511        This environment variable overrides `$EDITOR` and `$VISUAL`.
 512        It is used by several Git commands when, on interactive mode,
 513        an editor is to be launched. See also linkgit:git-var[1]
 514        and the `core.editor` option in linkgit:git-config[1].
 515
 516`GIT_SSH`::
 517`GIT_SSH_COMMAND`::
 518        If either of these environment variables is set then 'git fetch'
 519        and 'git push' will use the specified command instead of 'ssh'
 520        when they need to connect to a remote system.
 521        The command will be given exactly two or four arguments: the
 522        'username@host' (or just 'host') from the URL and the shell
 523        command to execute on that remote system, optionally preceded by
 524        `-p` (literally) and the 'port' from the URL when it specifies
 525        something other than the default SSH port.
 526+
 527`$GIT_SSH_COMMAND` takes precedence over `$GIT_SSH`, and is interpreted
 528by the shell, which allows additional arguments to be included.
 529`$GIT_SSH` on the other hand must be just the path to a program
 530(which can be a wrapper shell script, if additional arguments are
 531needed).
 532+
 533Usually it is easier to configure any desired options through your
 534personal `.ssh/config` file.  Please consult your ssh documentation
 535for further details.
 536
 537`GIT_SSH_VARIANT`::
 538        If this environment variable is set, it overrides Git's autodetection
 539        whether `GIT_SSH`/`GIT_SSH_COMMAND`/`core.sshCommand` refer to OpenSSH,
 540        plink or tortoiseplink. This variable overrides the config setting
 541        `ssh.variant` that serves the same purpose.
 542
 543`GIT_ASKPASS`::
 544        If this environment variable is set, then Git commands which need to
 545        acquire passwords or passphrases (e.g. for HTTP or IMAP authentication)
 546        will call this program with a suitable prompt as command-line argument
 547        and read the password from its STDOUT. See also the `core.askPass`
 548        option in linkgit:git-config[1].
 549
 550`GIT_TERMINAL_PROMPT`::
 551        If this environment variable is set to `0`, git will not prompt
 552        on the terminal (e.g., when asking for HTTP authentication).
 553
 554`GIT_CONFIG_NOSYSTEM`::
 555        Whether to skip reading settings from the system-wide
 556        `$(prefix)/etc/gitconfig` file.  This environment variable can
 557        be used along with `$HOME` and `$XDG_CONFIG_HOME` to create a
 558        predictable environment for a picky script, or you can set it
 559        temporarily to avoid using a buggy `/etc/gitconfig` file while
 560        waiting for someone with sufficient permissions to fix it.
 561
 562`GIT_FLUSH`::
 563        If this environment variable is set to "1", then commands such
 564        as 'git blame' (in incremental mode), 'git rev-list', 'git log',
 565        'git check-attr' and 'git check-ignore' will
 566        force a flush of the output stream after each record have been
 567        flushed. If this
 568        variable is set to "0", the output of these commands will be done
 569        using completely buffered I/O.   If this environment variable is
 570        not set, Git will choose buffered or record-oriented flushing
 571        based on whether stdout appears to be redirected to a file or not.
 572
 573`GIT_TRACE`::
 574        Enables general trace messages, e.g. alias expansion, built-in
 575        command execution and external command execution.
 576+
 577If this variable is set to "1", "2" or "true" (comparison
 578is case insensitive), trace messages will be printed to
 579stderr.
 580+
 581If the variable is set to an integer value greater than 2
 582and lower than 10 (strictly) then Git will interpret this
 583value as an open file descriptor and will try to write the
 584trace messages into this file descriptor.
 585+
 586Alternatively, if the variable is set to an absolute path
 587(starting with a '/' character), Git will interpret this
 588as a file path and will try to write the trace messages
 589into it.
 590+
 591Unsetting the variable, or setting it to empty, "0" or
 592"false" (case insensitive) disables trace messages.
 593
 594`GIT_TRACE_PACK_ACCESS`::
 595        Enables trace messages for all accesses to any packs. For each
 596        access, the pack file name and an offset in the pack is
 597        recorded. This may be helpful for troubleshooting some
 598        pack-related performance problems.
 599        See `GIT_TRACE` for available trace output options.
 600
 601`GIT_TRACE_PACKET`::
 602        Enables trace messages for all packets coming in or out of a
 603        given program. This can help with debugging object negotiation
 604        or other protocol issues. Tracing is turned off at a packet
 605        starting with "PACK" (but see `GIT_TRACE_PACKFILE` below).
 606        See `GIT_TRACE` for available trace output options.
 607
 608`GIT_TRACE_PACKFILE`::
 609        Enables tracing of packfiles sent or received by a
 610        given program. Unlike other trace output, this trace is
 611        verbatim: no headers, and no quoting of binary data. You almost
 612        certainly want to direct into a file (e.g.,
 613        `GIT_TRACE_PACKFILE=/tmp/my.pack`) rather than displaying it on
 614        the terminal or mixing it with other trace output.
 615+
 616Note that this is currently only implemented for the client side
 617of clones and fetches.
 618
 619`GIT_TRACE_PERFORMANCE`::
 620        Enables performance related trace messages, e.g. total execution
 621        time of each Git command.
 622        See `GIT_TRACE` for available trace output options.
 623
 624`GIT_TRACE_SETUP`::
 625        Enables trace messages printing the .git, working tree and current
 626        working directory after Git has completed its setup phase.
 627        See `GIT_TRACE` for available trace output options.
 628
 629`GIT_TRACE_SHALLOW`::
 630        Enables trace messages that can help debugging fetching /
 631        cloning of shallow repositories.
 632        See `GIT_TRACE` for available trace output options.
 633
 634`GIT_TRACE_CURL`::
 635        Enables a curl full trace dump of all incoming and outgoing data,
 636        including descriptive information, of the git transport protocol.
 637        This is similar to doing curl `--trace-ascii` on the command line.
 638        This option overrides setting the `GIT_CURL_VERBOSE` environment
 639        variable.
 640        See `GIT_TRACE` for available trace output options.
 641
 642`GIT_LITERAL_PATHSPECS`::
 643        Setting this variable to `1` will cause Git to treat all
 644        pathspecs literally, rather than as glob patterns. For example,
 645        running `GIT_LITERAL_PATHSPECS=1 git log -- '*.c'` will search
 646        for commits that touch the path `*.c`, not any paths that the
 647        glob `*.c` matches. You might want this if you are feeding
 648        literal paths to Git (e.g., paths previously given to you by
 649        `git ls-tree`, `--raw` diff output, etc).
 650
 651`GIT_GLOB_PATHSPECS`::
 652        Setting this variable to `1` will cause Git to treat all
 653        pathspecs as glob patterns (aka "glob" magic).
 654
 655`GIT_NOGLOB_PATHSPECS`::
 656        Setting this variable to `1` will cause Git to treat all
 657        pathspecs as literal (aka "literal" magic).
 658
 659`GIT_ICASE_PATHSPECS`::
 660        Setting this variable to `1` will cause Git to treat all
 661        pathspecs as case-insensitive.
 662
 663`GIT_REFLOG_ACTION`::
 664        When a ref is updated, reflog entries are created to keep
 665        track of the reason why the ref was updated (which is
 666        typically the name of the high-level command that updated
 667        the ref), in addition to the old and new values of the ref.
 668        A scripted Porcelain command can use set_reflog_action
 669        helper function in `git-sh-setup` to set its name to this
 670        variable when it is invoked as the top level command by the
 671        end user, to be recorded in the body of the reflog.
 672
 673`GIT_REF_PARANOIA`::
 674        If set to `1`, include broken or badly named refs when iterating
 675        over lists of refs. In a normal, non-corrupted repository, this
 676        does nothing. However, enabling it may help git to detect and
 677        abort some operations in the presence of broken refs. Git sets
 678        this variable automatically when performing destructive
 679        operations like linkgit:git-prune[1]. You should not need to set
 680        it yourself unless you want to be paranoid about making sure
 681        an operation has touched every ref (e.g., because you are
 682        cloning a repository to make a backup).
 683
 684`GIT_ALLOW_PROTOCOL`::
 685        If set to a colon-separated list of protocols, behave as if
 686        `protocol.allow` is set to `never`, and each of the listed
 687        protocols has `protocol.<name>.allow` set to `always`
 688        (overriding any existing configuration). In other words, any
 689        protocol not mentioned will be disallowed (i.e., this is a
 690        whitelist, not a blacklist). See the description of
 691        `protocol.allow` in linkgit:git-config[1] for more details.
 692
 693`GIT_PROTOCOL_FROM_USER`::
 694        Set to 0 to prevent protocols used by fetch/push/clone which are
 695        configured to the `user` state.  This is useful to restrict recursive
 696        submodule initialization from an untrusted repository or for programs
 697        which feed potentially-untrusted URLS to git commands.  See
 698        linkgit:git-config[1] for more details.
 699
 700`GIT_PROTOCOL`::
 701        For internal use only.  Used in handshaking the wire protocol.
 702        Contains a colon ':' separated list of keys with optional values
 703        'key[=value]'.  Presence of unknown keys and values must be
 704        ignored.
 705
 706Discussion[[Discussion]]
 707------------------------
 708
 709More detail on the following is available from the
 710link:user-manual.html#git-concepts[Git concepts chapter of the
 711user-manual] and linkgit:gitcore-tutorial[7].
 712
 713A Git project normally consists of a working directory with a ".git"
 714subdirectory at the top level.  The .git directory contains, among other
 715things, a compressed object database representing the complete history
 716of the project, an "index" file which links that history to the current
 717contents of the working tree, and named pointers into that history such
 718as tags and branch heads.
 719
 720The object database contains objects of three main types: blobs, which
 721hold file data; trees, which point to blobs and other trees to build up
 722directory hierarchies; and commits, which each reference a single tree
 723and some number of parent commits.
 724
 725The commit, equivalent to what other systems call a "changeset" or
 726"version", represents a step in the project's history, and each parent
 727represents an immediately preceding step.  Commits with more than one
 728parent represent merges of independent lines of development.
 729
 730All objects are named by the SHA-1 hash of their contents, normally
 731written as a string of 40 hex digits.  Such names are globally unique.
 732The entire history leading up to a commit can be vouched for by signing
 733just that commit.  A fourth object type, the tag, is provided for this
 734purpose.
 735
 736When first created, objects are stored in individual files, but for
 737efficiency may later be compressed together into "pack files".
 738
 739Named pointers called refs mark interesting points in history.  A ref
 740may contain the SHA-1 name of an object or the name of another ref.  Refs
 741with names beginning `ref/head/` contain the SHA-1 name of the most
 742recent commit (or "head") of a branch under development.  SHA-1 names of
 743tags of interest are stored under `ref/tags/`.  A special ref named
 744`HEAD` contains the name of the currently checked-out branch.
 745
 746The index file is initialized with a list of all paths and, for each
 747path, a blob object and a set of attributes.  The blob object represents
 748the contents of the file as of the head of the current branch.  The
 749attributes (last modified time, size, etc.) are taken from the
 750corresponding file in the working tree.  Subsequent changes to the
 751working tree can be found by comparing these attributes.  The index may
 752be updated with new content, and new commits may be created from the
 753content stored in the index.
 754
 755The index is also capable of storing multiple entries (called "stages")
 756for a given pathname.  These stages are used to hold the various
 757unmerged version of a file when a merge is in progress.
 758
 759FURTHER DOCUMENTATION
 760---------------------
 761
 762See the references in the "description" section to get started
 763using Git.  The following is probably more detail than necessary
 764for a first-time user.
 765
 766The link:user-manual.html#git-concepts[Git concepts chapter of the
 767user-manual] and linkgit:gitcore-tutorial[7] both provide
 768introductions to the underlying Git architecture.
 769
 770See linkgit:gitworkflows[7] for an overview of recommended workflows.
 771
 772See also the link:howto-index.html[howto] documents for some useful
 773examples.
 774
 775The internals are documented in the
 776link:technical/api-index.html[Git API documentation].
 777
 778Users migrating from CVS may also want to
 779read linkgit:gitcvs-migration[7].
 780
 781
 782Authors
 783-------
 784Git was started by Linus Torvalds, and is currently maintained by Junio
 785C Hamano. Numerous contributions have come from the Git mailing list
 786<git@vger.kernel.org>.  http://www.openhub.net/p/git/contributors/summary
 787gives you a more complete list of contributors.
 788
 789If you have a clone of git.git itself, the
 790output of linkgit:git-shortlog[1] and linkgit:git-blame[1] can show you
 791the authors for specific parts of the project.
 792
 793Reporting Bugs
 794--------------
 795
 796Report bugs to the Git mailing list <git@vger.kernel.org> where the
 797development and maintenance is primarily done.  You do not have to be
 798subscribed to the list to send a message there.
 799
 800SEE ALSO
 801--------
 802linkgit:gittutorial[7], linkgit:gittutorial-2[7],
 803linkgit:giteveryday[7], linkgit:gitcvs-migration[7],
 804linkgit:gitglossary[7], linkgit:gitcore-tutorial[7],
 805linkgit:gitcli[7], link:user-manual.html[The Git User's Manual],
 806linkgit:gitworkflows[7]
 807
 808GIT
 809---
 810Part of the linkgit:git[1] suite