Documentation / git.txton commit CodingGuidelines: Add a section on writing documentation (c455bd8)
   1git(1)
   2======
   3
   4NAME
   5----
   6git - the stupid content tracker
   7
   8
   9SYNOPSIS
  10--------
  11[verse]
  12'git' [--version] [--exec-path[=<path>]] [--html-path]
  13    [-p|--paginate|--no-pager] [--no-replace-objects]
  14    [--bare] [--git-dir=<path>] [--work-tree=<path>]
  15    [-c <name>=<value>]
  16    [--help] <command> [<args>]
  17
  18DESCRIPTION
  19-----------
  20Git is a fast, scalable, distributed revision control system with an
  21unusually rich command set that provides both high-level operations
  22and full access to internals.
  23
  24See linkgit:gittutorial[7] to get started, then see
  25link:everyday.html[Everyday Git] for a useful minimum set of commands, and
  26"man git-commandname" for documentation of each command.  CVS users may
  27also want to read linkgit:gitcvs-migration[7].  See
  28the link:user-manual.html[Git User's Manual] for a more in-depth
  29introduction.
  30
  31The '<command>' is either a name of a Git command (see below) or an alias
  32as defined in the configuration file (see linkgit:git-config[1]).
  33
  34Formatted and hyperlinked version of the latest git
  35documentation can be viewed at
  36`http://www.kernel.org/pub/software/scm/git/docs/`.
  37
  38ifdef::stalenotes[]
  39[NOTE]
  40============
  41
  42You are reading the documentation for the latest (possibly
  43unreleased) version of git, that is available from 'master'
  44branch of the `git.git` repository.
  45Documentation for older releases are available here:
  46
  47* link:v1.7.3.2/git.html[documentation for release 1.7.3.2]
  48
  49* release notes for
  50  link:RelNotes/1.7.3.2.txt[1.7.3.2],
  51  link:RelNotes/1.7.3.1.txt[1.7.3.1],
  52  link:RelNotes/1.7.3.txt[1.7.3].
  53
  54* link:v1.7.2.3/git.html[documentation for release 1.7.2.3]
  55
  56* release notes for
  57  link:RelNotes/1.7.2.3.txt[1.7.2.3],
  58  link:RelNotes/1.7.2.2.txt[1.7.2.2],
  59  link:RelNotes/1.7.2.1.txt[1.7.2.1],
  60  link:RelNotes/1.7.2.txt[1.7.2].
  61
  62* link:v1.7.1.2/git.html[documentation for release 1.7.1.2]
  63
  64* release notes for
  65  link:RelNotes/1.7.1.2.txt[1.7.1.2],
  66  link:RelNotes/1.7.1.1.txt[1.7.1.1],
  67  link:RelNotes/1.7.1.txt[1.7.1].
  68
  69* link:v1.7.0.7/git.html[documentation for release 1.7.0.7]
  70
  71* release notes for
  72  link:RelNotes/1.7.0.7.txt[1.7.0.7],
  73  link:RelNotes/1.7.0.6.txt[1.7.0.6],
  74  link:RelNotes/1.7.0.5.txt[1.7.0.5],
  75  link:RelNotes/1.7.0.4.txt[1.7.0.4],
  76  link:RelNotes/1.7.0.3.txt[1.7.0.3],
  77  link:RelNotes/1.7.0.2.txt[1.7.0.2],
  78  link:RelNotes/1.7.0.1.txt[1.7.0.1],
  79  link:RelNotes/1.7.0.txt[1.7.0].
  80
  81* link:v1.6.6.2/git.html[documentation for release 1.6.6.2]
  82
  83* release notes for
  84  link:RelNotes/1.6.6.2.txt[1.6.6.2],
  85  link:RelNotes/1.6.6.1.txt[1.6.6.1],
  86  link:RelNotes/1.6.6.txt[1.6.6].
  87
  88* link:v1.6.5.8/git.html[documentation for release 1.6.5.8]
  89
  90* release notes for
  91  link:RelNotes/1.6.5.8.txt[1.6.5.8],
  92  link:RelNotes/1.6.5.7.txt[1.6.5.7],
  93  link:RelNotes/1.6.5.6.txt[1.6.5.6],
  94  link:RelNotes/1.6.5.5.txt[1.6.5.5],
  95  link:RelNotes/1.6.5.4.txt[1.6.5.4],
  96  link:RelNotes/1.6.5.3.txt[1.6.5.3],
  97  link:RelNotes/1.6.5.2.txt[1.6.5.2],
  98  link:RelNotes/1.6.5.1.txt[1.6.5.1],
  99  link:RelNotes/1.6.5.txt[1.6.5].
 100
 101* link:v1.6.4.4/git.html[documentation for release 1.6.4.4]
 102
 103* release notes for
 104  link:RelNotes/1.6.4.4.txt[1.6.4.4],
 105  link:RelNotes/1.6.4.3.txt[1.6.4.3],
 106  link:RelNotes/1.6.4.2.txt[1.6.4.2],
 107  link:RelNotes/1.6.4.1.txt[1.6.4.1],
 108  link:RelNotes/1.6.4.txt[1.6.4].
 109
 110* link:v1.6.3.4/git.html[documentation for release 1.6.3.4]
 111
 112* release notes for
 113  link:RelNotes/1.6.3.4.txt[1.6.3.4],
 114  link:RelNotes/1.6.3.3.txt[1.6.3.3],
 115  link:RelNotes/1.6.3.2.txt[1.6.3.2],
 116  link:RelNotes/1.6.3.1.txt[1.6.3.1],
 117  link:RelNotes/1.6.3.txt[1.6.3].
 118
 119* release notes for
 120  link:RelNotes/1.6.2.5.txt[1.6.2.5],
 121  link:RelNotes/1.6.2.4.txt[1.6.2.4],
 122  link:RelNotes/1.6.2.3.txt[1.6.2.3],
 123  link:RelNotes/1.6.2.2.txt[1.6.2.2],
 124  link:RelNotes/1.6.2.1.txt[1.6.2.1],
 125  link:RelNotes/1.6.2.txt[1.6.2].
 126
 127* link:v1.6.1.3/git.html[documentation for release 1.6.1.3]
 128
 129* release notes for
 130  link:RelNotes/1.6.1.3.txt[1.6.1.3],
 131  link:RelNotes/1.6.1.2.txt[1.6.1.2],
 132  link:RelNotes/1.6.1.1.txt[1.6.1.1],
 133  link:RelNotes/1.6.1.txt[1.6.1].
 134
 135* link:v1.6.0.6/git.html[documentation for release 1.6.0.6]
 136
 137* release notes for
 138  link:RelNotes/1.6.0.6.txt[1.6.0.6],
 139  link:RelNotes/1.6.0.5.txt[1.6.0.5],
 140  link:RelNotes/1.6.0.4.txt[1.6.0.4],
 141  link:RelNotes/1.6.0.3.txt[1.6.0.3],
 142  link:RelNotes/1.6.0.2.txt[1.6.0.2],
 143  link:RelNotes/1.6.0.1.txt[1.6.0.1],
 144  link:RelNotes/1.6.0.txt[1.6.0].
 145
 146* link:v1.5.6.6/git.html[documentation for release 1.5.6.6]
 147
 148* release notes for
 149  link:RelNotes/1.5.6.6.txt[1.5.6.6],
 150  link:RelNotes/1.5.6.5.txt[1.5.6.5],
 151  link:RelNotes/1.5.6.4.txt[1.5.6.4],
 152  link:RelNotes/1.5.6.3.txt[1.5.6.3],
 153  link:RelNotes/1.5.6.2.txt[1.5.6.2],
 154  link:RelNotes/1.5.6.1.txt[1.5.6.1],
 155  link:RelNotes/1.5.6.txt[1.5.6].
 156
 157* link:v1.5.5.6/git.html[documentation for release 1.5.5.6]
 158
 159* release notes for
 160  link:RelNotes/1.5.5.6.txt[1.5.5.6],
 161  link:RelNotes/1.5.5.5.txt[1.5.5.5],
 162  link:RelNotes/1.5.5.4.txt[1.5.5.4],
 163  link:RelNotes/1.5.5.3.txt[1.5.5.3],
 164  link:RelNotes/1.5.5.2.txt[1.5.5.2],
 165  link:RelNotes/1.5.5.1.txt[1.5.5.1],
 166  link:RelNotes/1.5.5.txt[1.5.5].
 167
 168* link:v1.5.4.7/git.html[documentation for release 1.5.4.7]
 169
 170* release notes for
 171  link:RelNotes/1.5.4.7.txt[1.5.4.7],
 172  link:RelNotes/1.5.4.6.txt[1.5.4.6],
 173  link:RelNotes/1.5.4.5.txt[1.5.4.5],
 174  link:RelNotes/1.5.4.4.txt[1.5.4.4],
 175  link:RelNotes/1.5.4.3.txt[1.5.4.3],
 176  link:RelNotes/1.5.4.2.txt[1.5.4.2],
 177  link:RelNotes/1.5.4.1.txt[1.5.4.1],
 178  link:RelNotes/1.5.4.txt[1.5.4].
 179
 180* link:v1.5.3.8/git.html[documentation for release 1.5.3.8]
 181
 182* release notes for
 183  link:RelNotes/1.5.3.8.txt[1.5.3.8],
 184  link:RelNotes/1.5.3.7.txt[1.5.3.7],
 185  link:RelNotes/1.5.3.6.txt[1.5.3.6],
 186  link:RelNotes/1.5.3.5.txt[1.5.3.5],
 187  link:RelNotes/1.5.3.4.txt[1.5.3.4],
 188  link:RelNotes/1.5.3.3.txt[1.5.3.3],
 189  link:RelNotes/1.5.3.2.txt[1.5.3.2],
 190  link:RelNotes/1.5.3.1.txt[1.5.3.1],
 191  link:RelNotes/1.5.3.txt[1.5.3].
 192
 193* link:v1.5.2.5/git.html[documentation for release 1.5.2.5]
 194
 195* release notes for
 196  link:RelNotes/1.5.2.5.txt[1.5.2.5],
 197  link:RelNotes/1.5.2.4.txt[1.5.2.4],
 198  link:RelNotes/1.5.2.3.txt[1.5.2.3],
 199  link:RelNotes/1.5.2.2.txt[1.5.2.2],
 200  link:RelNotes/1.5.2.1.txt[1.5.2.1],
 201  link:RelNotes/1.5.2.txt[1.5.2].
 202
 203* link:v1.5.1.6/git.html[documentation for release 1.5.1.6]
 204
 205* release notes for
 206  link:RelNotes/1.5.1.6.txt[1.5.1.6],
 207  link:RelNotes/1.5.1.5.txt[1.5.1.5],
 208  link:RelNotes/1.5.1.4.txt[1.5.1.4],
 209  link:RelNotes/1.5.1.3.txt[1.5.1.3],
 210  link:RelNotes/1.5.1.2.txt[1.5.1.2],
 211  link:RelNotes/1.5.1.1.txt[1.5.1.1],
 212  link:RelNotes/1.5.1.txt[1.5.1].
 213
 214* link:v1.5.0.7/git.html[documentation for release 1.5.0.7]
 215
 216* release notes for
 217  link:RelNotes/1.5.0.7.txt[1.5.0.7],
 218  link:RelNotes/1.5.0.6.txt[1.5.0.6],
 219  link:RelNotes/1.5.0.5.txt[1.5.0.5],
 220  link:RelNotes/1.5.0.3.txt[1.5.0.3],
 221  link:RelNotes/1.5.0.2.txt[1.5.0.2],
 222  link:RelNotes/1.5.0.1.txt[1.5.0.1],
 223  link:RelNotes/1.5.0.txt[1.5.0].
 224
 225* documentation for release link:v1.4.4.4/git.html[1.4.4.4],
 226  link:v1.3.3/git.html[1.3.3],
 227  link:v1.2.6/git.html[1.2.6],
 228  link:v1.0.13/git.html[1.0.13].
 229
 230============
 231
 232endif::stalenotes[]
 233
 234OPTIONS
 235-------
 236--version::
 237        Prints the git suite version that the 'git' program came from.
 238
 239--help::
 240        Prints the synopsis and a list of the most commonly used
 241        commands. If the option '--all' or '-a' is given then all
 242        available commands are printed. If a git command is named this
 243        option will bring up the manual page for that command.
 244+
 245Other options are available to control how the manual page is
 246displayed. See linkgit:git-help[1] for more information,
 247because `git --help ...` is converted internally into `git
 248help ...`.
 249
 250-c <name>=<value>::
 251        Pass a configuration parameter to the command. The value
 252        given will override values from configuration files.
 253        The <name> is expected in the same format as listed by
 254        'git config' (subkeys separated by dots).
 255
 256--exec-path[=<path>]::
 257        Path to wherever your core git programs are installed.
 258        This can also be controlled by setting the GIT_EXEC_PATH
 259        environment variable. If no path is given, 'git' will print
 260        the current setting and then exit.
 261
 262--html-path::
 263        Print the path to wherever your git HTML documentation is installed
 264        and exit.
 265
 266-p::
 267--paginate::
 268        Pipe all output into 'less' (or if set, $PAGER) if standard
 269        output is a terminal.  This overrides the `pager.<cmd>`
 270        configuration options (see the "Configuration Mechanism" section
 271        below).
 272
 273--no-pager::
 274        Do not pipe git output into a pager.
 275
 276--git-dir=<path>::
 277        Set the path to the repository. This can also be controlled by
 278        setting the GIT_DIR environment variable. It can be an absolute
 279        path or relative path to current working directory.
 280
 281--work-tree=<path>::
 282        Set the path to the working tree.  The value will not be
 283        used in combination with repositories found automatically in
 284        a .git directory (i.e. $GIT_DIR is not set).
 285        This can also be controlled by setting the GIT_WORK_TREE
 286        environment variable and the core.worktree configuration
 287        variable. It can be an absolute path or relative path to
 288        the directory specified by --git-dir or GIT_DIR.
 289        Note: If --git-dir or GIT_DIR are specified but none of
 290        --work-tree, GIT_WORK_TREE and core.worktree is specified,
 291        the current working directory is regarded as the top directory
 292        of your working tree.
 293
 294--bare::
 295        Treat the repository as a bare repository.  If GIT_DIR
 296        environment is not set, it is set to the current working
 297        directory.
 298
 299--no-replace-objects::
 300        Do not use replacement refs to replace git objects. See
 301        linkgit:git-replace[1] for more information.
 302
 303
 304FURTHER DOCUMENTATION
 305---------------------
 306
 307See the references above to get started using git.  The following is
 308probably more detail than necessary for a first-time user.
 309
 310The link:user-manual.html#git-concepts[git concepts chapter of the
 311user-manual] and linkgit:gitcore-tutorial[7] both provide
 312introductions to the underlying git architecture.
 313
 314See linkgit:gitworkflows[7] for an overview of recommended workflows.
 315
 316See also the link:howto-index.html[howto] documents for some useful
 317examples.
 318
 319The internals are documented in the
 320link:technical/api-index.html[GIT API documentation].
 321
 322GIT COMMANDS
 323------------
 324
 325We divide git into high level ("porcelain") commands and low level
 326("plumbing") commands.
 327
 328High-level commands (porcelain)
 329-------------------------------
 330
 331We separate the porcelain commands into the main commands and some
 332ancillary user utilities.
 333
 334Main porcelain commands
 335~~~~~~~~~~~~~~~~~~~~~~~
 336
 337include::cmds-mainporcelain.txt[]
 338
 339Ancillary Commands
 340~~~~~~~~~~~~~~~~~~
 341Manipulators:
 342
 343include::cmds-ancillarymanipulators.txt[]
 344
 345Interrogators:
 346
 347include::cmds-ancillaryinterrogators.txt[]
 348
 349
 350Interacting with Others
 351~~~~~~~~~~~~~~~~~~~~~~~
 352
 353These commands are to interact with foreign SCM and with other
 354people via patch over e-mail.
 355
 356include::cmds-foreignscminterface.txt[]
 357
 358
 359Low-level commands (plumbing)
 360-----------------------------
 361
 362Although git includes its
 363own porcelain layer, its low-level commands are sufficient to support
 364development of alternative porcelains.  Developers of such porcelains
 365might start by reading about linkgit:git-update-index[1] and
 366linkgit:git-read-tree[1].
 367
 368The interface (input, output, set of options and the semantics)
 369to these low-level commands are meant to be a lot more stable
 370than Porcelain level commands, because these commands are
 371primarily for scripted use.  The interface to Porcelain commands
 372on the other hand are subject to change in order to improve the
 373end user experience.
 374
 375The following description divides
 376the low-level commands into commands that manipulate objects (in
 377the repository, index, and working tree), commands that interrogate and
 378compare objects, and commands that move objects and references between
 379repositories.
 380
 381
 382Manipulation commands
 383~~~~~~~~~~~~~~~~~~~~~
 384
 385include::cmds-plumbingmanipulators.txt[]
 386
 387
 388Interrogation commands
 389~~~~~~~~~~~~~~~~~~~~~~
 390
 391include::cmds-plumbinginterrogators.txt[]
 392
 393In general, the interrogate commands do not touch the files in
 394the working tree.
 395
 396
 397Synching repositories
 398~~~~~~~~~~~~~~~~~~~~~
 399
 400include::cmds-synchingrepositories.txt[]
 401
 402The following are helper commands used by the above; end users
 403typically do not use them directly.
 404
 405include::cmds-synchelpers.txt[]
 406
 407
 408Internal helper commands
 409~~~~~~~~~~~~~~~~~~~~~~~~
 410
 411These are internal helper commands used by other commands; end
 412users typically do not use them directly.
 413
 414include::cmds-purehelpers.txt[]
 415
 416
 417Configuration Mechanism
 418-----------------------
 419
 420Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file
 421is used to hold per-repository configuration options.  It is a
 422simple text file modeled after `.ini` format familiar to some
 423people.  Here is an example:
 424
 425------------
 426#
 427# A '#' or ';' character indicates a comment.
 428#
 429
 430; core variables
 431[core]
 432        ; Don't trust file modes
 433        filemode = false
 434
 435; user identity
 436[user]
 437        name = "Junio C Hamano"
 438        email = "junkio@twinsun.com"
 439
 440------------
 441
 442Various commands read from the configuration file and adjust
 443their operation accordingly.  See linkgit:git-config[1] for a
 444list.
 445
 446
 447Identifier Terminology
 448----------------------
 449<object>::
 450        Indicates the object name for any type of object.
 451
 452<blob>::
 453        Indicates a blob object name.
 454
 455<tree>::
 456        Indicates a tree object name.
 457
 458<commit>::
 459        Indicates a commit object name.
 460
 461<tree-ish>::
 462        Indicates a tree, commit or tag object name.  A
 463        command that takes a <tree-ish> argument ultimately wants to
 464        operate on a <tree> object but automatically dereferences
 465        <commit> and <tag> objects that point at a <tree>.
 466
 467<commit-ish>::
 468        Indicates a commit or tag object name.  A
 469        command that takes a <commit-ish> argument ultimately wants to
 470        operate on a <commit> object but automatically dereferences
 471        <tag> objects that point at a <commit>.
 472
 473<type>::
 474        Indicates that an object type is required.
 475        Currently one of: `blob`, `tree`, `commit`, or `tag`.
 476
 477<file>::
 478        Indicates a filename - almost always relative to the
 479        root of the tree structure `GIT_INDEX_FILE` describes.
 480
 481Symbolic Identifiers
 482--------------------
 483Any git command accepting any <object> can also use the following
 484symbolic notation:
 485
 486HEAD::
 487        indicates the head of the current branch (i.e. the
 488        contents of `$GIT_DIR/HEAD`).
 489
 490<tag>::
 491        a valid tag 'name'
 492        (i.e. the contents of `$GIT_DIR/refs/tags/<tag>`).
 493
 494<head>::
 495        a valid head 'name'
 496        (i.e. the contents of `$GIT_DIR/refs/heads/<head>`).
 497
 498For a more complete list of ways to spell object names, see
 499"SPECIFYING REVISIONS" section in linkgit:gitrevisions[7].
 500
 501
 502File/Directory Structure
 503------------------------
 504
 505Please see the linkgit:gitrepository-layout[5] document.
 506
 507Read linkgit:githooks[5] for more details about each hook.
 508
 509Higher level SCMs may provide and manage additional information in the
 510`$GIT_DIR`.
 511
 512
 513Terminology
 514-----------
 515Please see linkgit:gitglossary[7].
 516
 517
 518Environment Variables
 519---------------------
 520Various git commands use the following environment variables:
 521
 522The git Repository
 523~~~~~~~~~~~~~~~~~~
 524These environment variables apply to 'all' core git commands. Nb: it
 525is worth noting that they may be used/overridden by SCMS sitting above
 526git so take care if using Cogito etc.
 527
 528'GIT_INDEX_FILE'::
 529        This environment allows the specification of an alternate
 530        index file. If not specified, the default of `$GIT_DIR/index`
 531        is used.
 532
 533'GIT_OBJECT_DIRECTORY'::
 534        If the object storage directory is specified via this
 535        environment variable then the sha1 directories are created
 536        underneath - otherwise the default `$GIT_DIR/objects`
 537        directory is used.
 538
 539'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
 540        Due to the immutable nature of git objects, old objects can be
 541        archived into shared, read-only directories. This variable
 542        specifies a ":" separated (on Windows ";" separated) list
 543        of git object directories which can be used to search for git
 544        objects. New objects will not be written to these directories.
 545
 546'GIT_DIR'::
 547        If the 'GIT_DIR' environment variable is set then it
 548        specifies a path to use instead of the default `.git`
 549        for the base of the repository.
 550
 551'GIT_WORK_TREE'::
 552        Set the path to the working tree.  The value will not be
 553        used in combination with repositories found automatically in
 554        a .git directory (i.e. $GIT_DIR is not set).
 555        This can also be controlled by the '--work-tree' command line
 556        option and the core.worktree configuration variable.
 557
 558'GIT_CEILING_DIRECTORIES'::
 559        This should be a colon-separated list of absolute paths.
 560        If set, it is a list of directories that git should not chdir
 561        up into while looking for a repository directory.
 562        It will not exclude the current working directory or
 563        a GIT_DIR set on the command line or in the environment.
 564        (Useful for excluding slow-loading network directories.)
 565
 566'GIT_DISCOVERY_ACROSS_FILESYSTEM'::
 567        When run in a directory that does not have ".git" repository
 568        directory, git tries to find such a directory in the parent
 569        directories to find the top of the working tree, but by default it
 570        does not cross filesystem boundaries.  This environment variable
 571        can be set to true to tell git not to stop at filesystem
 572        boundaries.  Like 'GIT_CEILING_DIRECTORIES', this will not affect
 573        an explicit repository directory set via 'GIT_DIR' or on the
 574        command line.
 575
 576git Commits
 577~~~~~~~~~~~
 578'GIT_AUTHOR_NAME'::
 579'GIT_AUTHOR_EMAIL'::
 580'GIT_AUTHOR_DATE'::
 581'GIT_COMMITTER_NAME'::
 582'GIT_COMMITTER_EMAIL'::
 583'GIT_COMMITTER_DATE'::
 584'EMAIL'::
 585        see linkgit:git-commit-tree[1]
 586
 587git Diffs
 588~~~~~~~~~
 589'GIT_DIFF_OPTS'::
 590        Only valid setting is "--unified=??" or "-u??" to set the
 591        number of context lines shown when a unified diff is created.
 592        This takes precedence over any "-U" or "--unified" option
 593        value passed on the git diff command line.
 594
 595'GIT_EXTERNAL_DIFF'::
 596        When the environment variable 'GIT_EXTERNAL_DIFF' is set, the
 597        program named by it is called, instead of the diff invocation
 598        described above.  For a path that is added, removed, or modified,
 599        'GIT_EXTERNAL_DIFF' is called with 7 parameters:
 600
 601        path old-file old-hex old-mode new-file new-hex new-mode
 602+
 603where:
 604
 605        <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the
 606                         contents of <old|new>,
 607        <old|new>-hex:: are the 40-hexdigit SHA1 hashes,
 608        <old|new>-mode:: are the octal representation of the file modes.
 609
 610+
 611The file parameters can point at the user's working file
 612(e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
 613when a new file is added), or a temporary file (e.g. `old-file` in the
 614index).  'GIT_EXTERNAL_DIFF' should not worry about unlinking the
 615temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits.
 616+
 617For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1
 618parameter, <path>.
 619
 620other
 621~~~~~
 622'GIT_MERGE_VERBOSITY'::
 623        A number controlling the amount of output shown by
 624        the recursive merge strategy.  Overrides merge.verbosity.
 625        See linkgit:git-merge[1]
 626
 627'GIT_PAGER'::
 628        This environment variable overrides `$PAGER`. If it is set
 629        to an empty string or to the value "cat", git will not launch
 630        a pager.  See also the `core.pager` option in
 631        linkgit:git-config[1].
 632
 633'GIT_SSH'::
 634        If this environment variable is set then 'git fetch'
 635        and 'git push' will use this command instead
 636        of 'ssh' when they need to connect to a remote system.
 637        The '$GIT_SSH' command will be given exactly two arguments:
 638        the 'username@host' (or just 'host') from the URL and the
 639        shell command to execute on that remote system.
 640+
 641To pass options to the program that you want to list in GIT_SSH
 642you will need to wrap the program and options into a shell script,
 643then set GIT_SSH to refer to the shell script.
 644+
 645Usually it is easier to configure any desired options through your
 646personal `.ssh/config` file.  Please consult your ssh documentation
 647for further details.
 648
 649'GIT_ASKPASS'::
 650        If this environment variable is set, then git commands which need to
 651        acquire passwords or passphrases (e.g. for HTTP or IMAP authentication)
 652        will call this program with a suitable prompt as command line argument
 653        and read the password from its STDOUT. See also the 'core.askpass'
 654        option in linkgit:git-config[1].
 655
 656'GIT_FLUSH'::
 657        If this environment variable is set to "1", then commands such
 658        as 'git blame' (in incremental mode), 'git rev-list', 'git log',
 659        and 'git whatchanged' will force a flush of the output stream
 660        after each commit-oriented record have been flushed.   If this
 661        variable is set to "0", the output of these commands will be done
 662        using completely buffered I/O.   If this environment variable is
 663        not set, git will choose buffered or record-oriented flushing
 664        based on whether stdout appears to be redirected to a file or not.
 665
 666'GIT_TRACE'::
 667        If this variable is set to "1", "2" or "true" (comparison
 668        is case insensitive), git will print `trace:` messages on
 669        stderr telling about alias expansion, built-in command
 670        execution and external command execution.
 671        If this variable is set to an integer value greater than 1
 672        and lower than 10 (strictly) then git will interpret this
 673        value as an open file descriptor and will try to write the
 674        trace messages into this file descriptor.
 675        Alternatively, if this variable is set to an absolute path
 676        (starting with a '/' character), git will interpret this
 677        as a file path and will try to write the trace messages
 678        into it.
 679
 680Discussion[[Discussion]]
 681------------------------
 682
 683More detail on the following is available from the
 684link:user-manual.html#git-concepts[git concepts chapter of the
 685user-manual] and linkgit:gitcore-tutorial[7].
 686
 687A git project normally consists of a working directory with a ".git"
 688subdirectory at the top level.  The .git directory contains, among other
 689things, a compressed object database representing the complete history
 690of the project, an "index" file which links that history to the current
 691contents of the working tree, and named pointers into that history such
 692as tags and branch heads.
 693
 694The object database contains objects of three main types: blobs, which
 695hold file data; trees, which point to blobs and other trees to build up
 696directory hierarchies; and commits, which each reference a single tree
 697and some number of parent commits.
 698
 699The commit, equivalent to what other systems call a "changeset" or
 700"version", represents a step in the project's history, and each parent
 701represents an immediately preceding step.  Commits with more than one
 702parent represent merges of independent lines of development.
 703
 704All objects are named by the SHA1 hash of their contents, normally
 705written as a string of 40 hex digits.  Such names are globally unique.
 706The entire history leading up to a commit can be vouched for by signing
 707just that commit.  A fourth object type, the tag, is provided for this
 708purpose.
 709
 710When first created, objects are stored in individual files, but for
 711efficiency may later be compressed together into "pack files".
 712
 713Named pointers called refs mark interesting points in history.  A ref
 714may contain the SHA1 name of an object or the name of another ref.  Refs
 715with names beginning `ref/head/` contain the SHA1 name of the most
 716recent commit (or "head") of a branch under development.  SHA1 names of
 717tags of interest are stored under `ref/tags/`.  A special ref named
 718`HEAD` contains the name of the currently checked-out branch.
 719
 720The index file is initialized with a list of all paths and, for each
 721path, a blob object and a set of attributes.  The blob object represents
 722the contents of the file as of the head of the current branch.  The
 723attributes (last modified time, size, etc.) are taken from the
 724corresponding file in the working tree.  Subsequent changes to the
 725working tree can be found by comparing these attributes.  The index may
 726be updated with new content, and new commits may be created from the
 727content stored in the index.
 728
 729The index is also capable of storing multiple entries (called "stages")
 730for a given pathname.  These stages are used to hold the various
 731unmerged version of a file when a merge is in progress.
 732
 733Authors
 734-------
 735* git's founding father is Linus Torvalds <torvalds@osdl.org>.
 736* The current git nurse is Junio C Hamano <gitster@pobox.com>.
 737* The git potty was written by Andreas Ericsson <ae@op5.se>.
 738* General upbringing is handled by the git-list <git@vger.kernel.org>.
 739
 740Documentation
 741--------------
 742The documentation for git suite was started by David Greaves
 743<david@dgreaves.com>, and later enhanced greatly by the
 744contributors on the git-list <git@vger.kernel.org>.
 745
 746Reporting Bugs
 747--------------
 748
 749Report bugs to the Git mailing list <git@vger.kernel.org> where the
 750development and maintenance is primarily done.  You do not have to be
 751subscribed to the list to send a message there.
 752
 753SEE ALSO
 754--------
 755linkgit:gittutorial[7], linkgit:gittutorial-2[7],
 756link:everyday.html[Everyday Git], linkgit:gitcvs-migration[7],
 757linkgit:gitglossary[7], linkgit:gitcore-tutorial[7],
 758linkgit:gitcli[7], link:user-manual.html[The Git User's Manual],
 759linkgit:gitworkflows[7]
 760
 761GIT
 762---
 763Part of the linkgit:git[1] suite