Documentation/git.txt

   1 git(1)
   2 ======
   3
   4 NAME
   5 ----
   6 git - the stupid content tracker
   7
   8
   9 SYNOPSIS
  10 --------
  11 [verse]
  12 'git' [--version] [--exec-path[=GIT_EXEC_PATH]] [--html-path]
  13     [-p|--paginate|--no-pager] [--no-replace-objects]
  14     [--bare] [--git-dir=GIT_DIR] [--work-tree=GIT_WORK_TREE]
  15     [-c name=value]
  16     [--help] COMMAND [ARGS]
  17
  18 DESCRIPTION
  19 -----------
  20 Git is a fast, scalable, distributed revision control system with an
  21 unusually rich command set that provides both high-level operations
  22 and full access to internals.
  23
  24 See linkgit:gittutorial[7] to get started, then see
  25 link:everyday.html[Everyday Git] for a useful minimum set of commands, and
  26 "man git-commandname" for documentation of each command.  CVS users may
  27 also want to read linkgit:gitcvs-migration[7].  See
  28 the link:user-manual.html[Git User's Manual] for a more in-depth
  29 introduction.
  30
  31 The COMMAND is either a name of a Git command (see below) or an alias
  32 as defined in the configuration file (see linkgit:git-config[1]).
  33
  34 Formatted and hyperlinked version of the latest git
  35 documentation can be viewed at
  36 `http://www.kernel.org/pub/software/scm/git/docs/`.
  37
  38 ifdef::stalenotes[]
  39 [NOTE]
  40 ============
  41
  42 You are reading the documentation for the latest (possibly
  43 unreleased) version of git, that is available from 'master'
  44 branch of the `git.git` repository.
  45 Documentation for older releases are available here:
  46
  47 * link:v1.7.1.1/git.html[documentation for release 1.7.1.1]
  48
  49 * release notes for
  50   link:RelNotes-1.7.1.1.txt[1.7.1.1],
  51   link:RelNotes-1.7.1.txt[1.7.1].
  52
  53 * link:v1.7.0.6/git.html[documentation for release 1.7.0.6]
  54
  55 * release notes for
  56   link:RelNotes-1.7.0.6.txt[1.7.0.6],
  57   link:RelNotes-1.7.0.5.txt[1.7.0.5],
  58   link:RelNotes-1.7.0.4.txt[1.7.0.4],
  59   link:RelNotes-1.7.0.3.txt[1.7.0.3],
  60   link:RelNotes-1.7.0.2.txt[1.7.0.2],
  61   link:RelNotes-1.7.0.1.txt[1.7.0.1],
  62   link:RelNotes-1.7.0.txt[1.7.0].
  63
  64 * link:v1.6.6.2/git.html[documentation for release 1.6.6.2]
  65
  66 * release notes for
  67   link:RelNotes-1.6.6.2.txt[1.6.6.2],
  68   link:RelNotes-1.6.6.1.txt[1.6.6.1],
  69   link:RelNotes-1.6.6.txt[1.6.6].
  70
  71 * link:v1.6.5.8/git.html[documentation for release 1.6.5.8]
  72
  73 * release notes for
  74   link:RelNotes-1.6.5.8.txt[1.6.5.8],
  75   link:RelNotes-1.6.5.7.txt[1.6.5.7],
  76   link:RelNotes-1.6.5.6.txt[1.6.5.6],
  77   link:RelNotes-1.6.5.5.txt[1.6.5.5],
  78   link:RelNotes-1.6.5.4.txt[1.6.5.4],
  79   link:RelNotes-1.6.5.3.txt[1.6.5.3],
  80   link:RelNotes-1.6.5.2.txt[1.6.5.2],
  81   link:RelNotes-1.6.5.1.txt[1.6.5.1],
  82   link:RelNotes-1.6.5.txt[1.6.5].
  83
  84 * link:v1.6.4.4/git.html[documentation for release 1.6.4.4]
  85
  86 * release notes for
  87   link:RelNotes-1.6.4.4.txt[1.6.4.4],
  88   link:RelNotes-1.6.4.3.txt[1.6.4.3],
  89   link:RelNotes-1.6.4.2.txt[1.6.4.2],
  90   link:RelNotes-1.6.4.1.txt[1.6.4.1],
  91   link:RelNotes-1.6.4.txt[1.6.4].
  92
  93 * link:v1.6.3.4/git.html[documentation for release 1.6.3.4]
  94
  95 * release notes for
  96   link:RelNotes-1.6.3.4.txt[1.6.3.4],
  97   link:RelNotes-1.6.3.3.txt[1.6.3.3],
  98   link:RelNotes-1.6.3.2.txt[1.6.3.2],
  99   link:RelNotes-1.6.3.1.txt[1.6.3.1],
 100   link:RelNotes-1.6.3.txt[1.6.3].
 101
 102 * release notes for
 103   link:RelNotes-1.6.2.5.txt[1.6.2.5],
 104   link:RelNotes-1.6.2.4.txt[1.6.2.4],
 105   link:RelNotes-1.6.2.3.txt[1.6.2.3],
 106   link:RelNotes-1.6.2.2.txt[1.6.2.2],
 107   link:RelNotes-1.6.2.1.txt[1.6.2.1],
 108   link:RelNotes-1.6.2.txt[1.6.2].
 109
 110 * link:v1.6.1.3/git.html[documentation for release 1.6.1.3]
 111
 112 * release notes for
 113   link:RelNotes-1.6.1.3.txt[1.6.1.3],
 114   link:RelNotes-1.6.1.2.txt[1.6.1.2],
 115   link:RelNotes-1.6.1.1.txt[1.6.1.1],
 116   link:RelNotes-1.6.1.txt[1.6.1].
 117
 118 * link:v1.6.0.6/git.html[documentation for release 1.6.0.6]
 119
 120 * release notes for
 121   link:RelNotes-1.6.0.6.txt[1.6.0.6],
 122   link:RelNotes-1.6.0.5.txt[1.6.0.5],
 123   link:RelNotes-1.6.0.4.txt[1.6.0.4],
 124   link:RelNotes-1.6.0.3.txt[1.6.0.3],
 125   link:RelNotes-1.6.0.2.txt[1.6.0.2],
 126   link:RelNotes-1.6.0.1.txt[1.6.0.1],
 127   link:RelNotes-1.6.0.txt[1.6.0].
 128
 129 * link:v1.5.6.6/git.html[documentation for release 1.5.6.6]
 130
 131 * release notes for
 132   link:RelNotes-1.5.6.6.txt[1.5.6.6],
 133   link:RelNotes-1.5.6.5.txt[1.5.6.5],
 134   link:RelNotes-1.5.6.4.txt[1.5.6.4],
 135   link:RelNotes-1.5.6.3.txt[1.5.6.3],
 136   link:RelNotes-1.5.6.2.txt[1.5.6.2],
 137   link:RelNotes-1.5.6.1.txt[1.5.6.1],
 138   link:RelNotes-1.5.6.txt[1.5.6].
 139
 140 * link:v1.5.5.6/git.html[documentation for release 1.5.5.6]
 141
 142 * release notes for
 143   link:RelNotes-1.5.5.6.txt[1.5.5.6],
 144   link:RelNotes-1.5.5.5.txt[1.5.5.5],
 145   link:RelNotes-1.5.5.4.txt[1.5.5.4],
 146   link:RelNotes-1.5.5.3.txt[1.5.5.3],
 147   link:RelNotes-1.5.5.2.txt[1.5.5.2],
 148   link:RelNotes-1.5.5.1.txt[1.5.5.1],
 149   link:RelNotes-1.5.5.txt[1.5.5].
 150
 151 * link:v1.5.4.7/git.html[documentation for release 1.5.4.7]
 152
 153 * release notes for
 154   link:RelNotes-1.5.4.7.txt[1.5.4.7],
 155   link:RelNotes-1.5.4.6.txt[1.5.4.6],
 156   link:RelNotes-1.5.4.5.txt[1.5.4.5],
 157   link:RelNotes-1.5.4.4.txt[1.5.4.4],
 158   link:RelNotes-1.5.4.3.txt[1.5.4.3],
 159   link:RelNotes-1.5.4.2.txt[1.5.4.2],
 160   link:RelNotes-1.5.4.1.txt[1.5.4.1],
 161   link:RelNotes-1.5.4.txt[1.5.4].
 162
 163 * link:v1.5.3.8/git.html[documentation for release 1.5.3.8]
 164
 165 * release notes for
 166   link:RelNotes-1.5.3.8.txt[1.5.3.8],
 167   link:RelNotes-1.5.3.7.txt[1.5.3.7],
 168   link:RelNotes-1.5.3.6.txt[1.5.3.6],
 169   link:RelNotes-1.5.3.5.txt[1.5.3.5],
 170   link:RelNotes-1.5.3.4.txt[1.5.3.4],
 171   link:RelNotes-1.5.3.3.txt[1.5.3.3],
 172   link:RelNotes-1.5.3.2.txt[1.5.3.2],
 173   link:RelNotes-1.5.3.1.txt[1.5.3.1],
 174   link:RelNotes-1.5.3.txt[1.5.3].
 175
 176 * link:v1.5.2.5/git.html[documentation for release 1.5.2.5]
 177
 178 * release notes for
 179   link:RelNotes-1.5.2.5.txt[1.5.2.5],
 180   link:RelNotes-1.5.2.4.txt[1.5.2.4],
 181   link:RelNotes-1.5.2.3.txt[1.5.2.3],
 182   link:RelNotes-1.5.2.2.txt[1.5.2.2],
 183   link:RelNotes-1.5.2.1.txt[1.5.2.1],
 184   link:RelNotes-1.5.2.txt[1.5.2].
 185
 186 * link:v1.5.1.6/git.html[documentation for release 1.5.1.6]
 187
 188 * release notes for
 189   link:RelNotes-1.5.1.6.txt[1.5.1.6],
 190   link:RelNotes-1.5.1.5.txt[1.5.1.5],
 191   link:RelNotes-1.5.1.4.txt[1.5.1.4],
 192   link:RelNotes-1.5.1.3.txt[1.5.1.3],
 193   link:RelNotes-1.5.1.2.txt[1.5.1.2],
 194   link:RelNotes-1.5.1.1.txt[1.5.1.1],
 195   link:RelNotes-1.5.1.txt[1.5.1].
 196
 197 * link:v1.5.0.7/git.html[documentation for release 1.5.0.7]
 198
 199 * release notes for
 200   link:RelNotes-1.5.0.7.txt[1.5.0.7],
 201   link:RelNotes-1.5.0.6.txt[1.5.0.6],
 202   link:RelNotes-1.5.0.5.txt[1.5.0.5],
 203   link:RelNotes-1.5.0.3.txt[1.5.0.3],
 204   link:RelNotes-1.5.0.2.txt[1.5.0.2],
 205   link:RelNotes-1.5.0.1.txt[1.5.0.1],
 206   link:RelNotes-1.5.0.txt[1.5.0].
 207
 208 * documentation for release link:v1.4.4.4/git.html[1.4.4.4],
 209   link:v1.3.3/git.html[1.3.3],
 210   link:v1.2.6/git.html[1.2.6],
 211   link:v1.0.13/git.html[1.0.13].
 212
 213 ============
 214
 215 endif::stalenotes[]
 216
 217 OPTIONS
 218 -------
 219 --version::
 220         Prints the git suite version that the 'git' program came from.
 221
 222 --help::
 223         Prints the synopsis and a list of the most commonly used
 224         commands. If the option '--all' or '-a' is given then all
 225         available commands are printed. If a git command is named this
 226         option will bring up the manual page for that command.
 227 +
 228 Other options are available to control how the manual page is
 229 displayed. See linkgit:git-help[1] for more information,
 230 because `git --help ...` is converted internally into `git
 231 help ...`.
 232
 233 -c <name>=<value>::
 234         Pass a configuration parameter to the command. The value
 235         given will override values from configuration files.
 236         The <name> is expected in the same format as listed by
 237         'git config' (subkeys separated by dots).
 238
 239 --exec-path::
 240         Path to wherever your core git programs are installed.
 241         This can also be controlled by setting the GIT_EXEC_PATH
 242         environment variable. If no path is given, 'git' will print
 243         the current setting and then exit.
 244
 245 --html-path::
 246         Print the path to wherever your git HTML documentation is installed
 247         and exit.
 248
 249 -p::
 250 --paginate::
 251         Pipe all output into 'less' (or if set, $PAGER) if standard
 252         output is a terminal.  This overrides the `pager.<cmd>`
 253         configuration options (see the "Configuration Mechanism" section
 254         below).
 255
 256 --no-pager::
 257         Do not pipe git output into a pager.
 258
 259 --git-dir=<path>::
 260         Set the path to the repository. This can also be controlled by
 261         setting the GIT_DIR environment variable. It can be an absolute
 262         path or relative path to current working directory.
 263
 264 --work-tree=<path>::
 265         Set the path to the working tree.  The value will not be
 266         used in combination with repositories found automatically in
 267         a .git directory (i.e. $GIT_DIR is not set).
 268         This can also be controlled by setting the GIT_WORK_TREE
 269         environment variable and the core.worktree configuration
 270         variable. It can be an absolute path or relative path to
 271         the directory specified by --git-dir or GIT_DIR.
 272         Note: If --git-dir or GIT_DIR are specified but none of
 273         --work-tree, GIT_WORK_TREE and core.worktree is specified,
 274         the current working directory is regarded as the top directory
 275         of your working tree.
 276
 277 --bare::
 278         Treat the repository as a bare repository.  If GIT_DIR
 279         environment is not set, it is set to the current working
 280         directory.
 281
 282 --no-replace-objects::
 283         Do not use replacement refs to replace git objects. See
 284         linkgit:git-replace[1] for more information.
 285
 286
 287 FURTHER DOCUMENTATION
 288 ---------------------
 289
 290 See the references above to get started using git.  The following is
 291 probably more detail than necessary for a first-time user.
 292
 293 The link:user-manual.html#git-concepts[git concepts chapter of the
 294 user-manual] and linkgit:gitcore-tutorial[7] both provide
 295 introductions to the underlying git architecture.
 296
 297 See linkgit:gitworkflows[7] for an overview of recommended workflows.
 298
 299 See also the link:howto-index.html[howto] documents for some useful
 300 examples.
 301
 302 The internals are documented in the
 303 link:technical/api-index.html[GIT API documentation].
 304
 305 GIT COMMANDS
 306 ------------
 307
 308 We divide git into high level ("porcelain") commands and low level
 309 ("plumbing") commands.
 310
 311 High-level commands (porcelain)
 312 -------------------------------
 313
 314 We separate the porcelain commands into the main commands and some
 315 ancillary user utilities.
 316
 317 Main porcelain commands
 318 ~~~~~~~~~~~~~~~~~~~~~~~
 319
 320 include::cmds-mainporcelain.txt[]
 321
 322 Ancillary Commands
 323 ~~~~~~~~~~~~~~~~~~
 324 Manipulators:
 325
 326 include::cmds-ancillarymanipulators.txt[]
 327
 328 Interrogators:
 329
 330 include::cmds-ancillaryinterrogators.txt[]
 331
 332
 333 Interacting with Others
 334 ~~~~~~~~~~~~~~~~~~~~~~~
 335
 336 These commands are to interact with foreign SCM and with other
 337 people via patch over e-mail.
 338
 339 include::cmds-foreignscminterface.txt[]
 340
 341
 342 Low-level commands (plumbing)
 343 -----------------------------
 344
 345 Although git includes its
 346 own porcelain layer, its low-level commands are sufficient to support
 347 development of alternative porcelains.  Developers of such porcelains
 348 might start by reading about linkgit:git-update-index[1] and
 349 linkgit:git-read-tree[1].
 350
 351 The interface (input, output, set of options and the semantics)
 352 to these low-level commands are meant to be a lot more stable
 353 than Porcelain level commands, because these commands are
 354 primarily for scripted use.  The interface to Porcelain commands
 355 on the other hand are subject to change in order to improve the
 356 end user experience.
 357
 358 The following description divides
 359 the low-level commands into commands that manipulate objects (in
 360 the repository, index, and working tree), commands that interrogate and
 361 compare objects, and commands that move objects and references between
 362 repositories.
 363
 364
 365 Manipulation commands
 366 ~~~~~~~~~~~~~~~~~~~~~
 367
 368 include::cmds-plumbingmanipulators.txt[]
 369
 370
 371 Interrogation commands
 372 ~~~~~~~~~~~~~~~~~~~~~~
 373
 374 include::cmds-plumbinginterrogators.txt[]
 375
 376 In general, the interrogate commands do not touch the files in
 377 the working tree.
 378
 379
 380 Synching repositories
 381 ~~~~~~~~~~~~~~~~~~~~~
 382
 383 include::cmds-synchingrepositories.txt[]
 384
 385 The following are helper commands used by the above; end users
 386 typically do not use them directly.
 387
 388 include::cmds-synchelpers.txt[]
 389
 390
 391 Internal helper commands
 392 ~~~~~~~~~~~~~~~~~~~~~~~~
 393
 394 These are internal helper commands used by other commands; end
 395 users typically do not use them directly.
 396
 397 include::cmds-purehelpers.txt[]
 398
 399
 400 Configuration Mechanism
 401 -----------------------
 402
 403 Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file
 404 is used to hold per-repository configuration options.  It is a
 405 simple text file modeled after `.ini` format familiar to some
 406 people.  Here is an example:
 407
 408 ------------
 409 #
 410 # A '#' or ';' character indicates a comment.
 411 #
 412
 413 ; core variables
 414 [core]
 415         ; Don't trust file modes
 416         filemode = false
 417
 418 ; user identity
 419 [user]
 420         name = "Junio C Hamano"
 421         email = "junkio@twinsun.com"
 422
 423 ------------
 424
 425 Various commands read from the configuration file and adjust
 426 their operation accordingly.  See linkgit:git-config[1] for a
 427 list.
 428
 429
 430 Identifier Terminology
 431 ----------------------
 432 <object>::
 433         Indicates the object name for any type of object.
 434
 435 <blob>::
 436         Indicates a blob object name.
 437
 438 <tree>::
 439         Indicates a tree object name.
 440
 441 <commit>::
 442         Indicates a commit object name.
 443
 444 <tree-ish>::
 445         Indicates a tree, commit or tag object name.  A
 446         command that takes a <tree-ish> argument ultimately wants to
 447         operate on a <tree> object but automatically dereferences
 448         <commit> and <tag> objects that point at a <tree>.
 449
 450 <commit-ish>::
 451         Indicates a commit or tag object name.  A
 452         command that takes a <commit-ish> argument ultimately wants to
 453         operate on a <commit> object but automatically dereferences
 454         <tag> objects that point at a <commit>.
 455
 456 <type>::
 457         Indicates that an object type is required.
 458         Currently one of: `blob`, `tree`, `commit`, or `tag`.
 459
 460 <file>::
 461         Indicates a filename - almost always relative to the
 462         root of the tree structure `GIT_INDEX_FILE` describes.
 463
 464 Symbolic Identifiers
 465 --------------------
 466 Any git command accepting any <object> can also use the following
 467 symbolic notation:
 468
 469 HEAD::
 470         indicates the head of the current branch (i.e. the
 471         contents of `$GIT_DIR/HEAD`).
 472
 473 <tag>::
 474         a valid tag 'name'
 475         (i.e. the contents of `$GIT_DIR/refs/tags/<tag>`).
 476
 477 <head>::
 478         a valid head 'name'
 479         (i.e. the contents of `$GIT_DIR/refs/heads/<head>`).
 480
 481 For a more complete list of ways to spell object names, see
 482 "SPECIFYING REVISIONS" section in linkgit:git-rev-parse[1].
 483
 484
 485 File/Directory Structure
 486 ------------------------
 487
 488 Please see the linkgit:gitrepository-layout[5] document.
 489
 490 Read linkgit:githooks[5] for more details about each hook.
 491
 492 Higher level SCMs may provide and manage additional information in the
 493 `$GIT_DIR`.
 494
 495
 496 Terminology
 497 -----------
 498 Please see linkgit:gitglossary[7].
 499
 500
 501 Environment Variables
 502 ---------------------
 503 Various git commands use the following environment variables:
 504
 505 The git Repository
 506 ~~~~~~~~~~~~~~~~~~
 507 These environment variables apply to 'all' core git commands. Nb: it
 508 is worth noting that they may be used/overridden by SCMS sitting above
 509 git so take care if using Cogito etc.
 510
 511 'GIT_INDEX_FILE'::
 512         This environment allows the specification of an alternate
 513         index file. If not specified, the default of `$GIT_DIR/index`
 514         is used.
 515
 516 'GIT_OBJECT_DIRECTORY'::
 517         If the object storage directory is specified via this
 518         environment variable then the sha1 directories are created
 519         underneath - otherwise the default `$GIT_DIR/objects`
 520         directory is used.
 521
 522 'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
 523         Due to the immutable nature of git objects, old objects can be
 524         archived into shared, read-only directories. This variable
 525         specifies a ":" separated (on Windows ";" separated) list
 526         of git object directories which can be used to search for git
 527         objects. New objects will not be written to these directories.
 528
 529 'GIT_DIR'::
 530         If the 'GIT_DIR' environment variable is set then it
 531         specifies a path to use instead of the default `.git`
 532         for the base of the repository.
 533
 534 'GIT_WORK_TREE'::
 535         Set the path to the working tree.  The value will not be
 536         used in combination with repositories found automatically in
 537         a .git directory (i.e. $GIT_DIR is not set).
 538         This can also be controlled by the '--work-tree' command line
 539         option and the core.worktree configuration variable.
 540
 541 'GIT_CEILING_DIRECTORIES'::
 542         This should be a colon-separated list of absolute paths.
 543         If set, it is a list of directories that git should not chdir
 544         up into while looking for a repository directory.
 545         It will not exclude the current working directory or
 546         a GIT_DIR set on the command line or in the environment.
 547         (Useful for excluding slow-loading network directories.)
 548
 549 'GIT_DISCOVERY_ACROSS_FILESYSTEM'::
 550         When run in a directory that does not have ".git" repository
 551         directory, git tries to find such a directory in the parent
 552         directories to find the top of the working tree, but by default it
 553         does not cross filesystem boundaries.  This environment variable
 554         can be set to true to tell git not to stop at filesystem
 555         boundaries.  Like 'GIT_CEILING_DIRECTORIES', this will not affect
 556         an explicit repository directory set via 'GIT_DIR' or on the
 557         command line.
 558
 559 git Commits
 560 ~~~~~~~~~~~
 561 'GIT_AUTHOR_NAME'::
 562 'GIT_AUTHOR_EMAIL'::
 563 'GIT_AUTHOR_DATE'::
 564 'GIT_COMMITTER_NAME'::
 565 'GIT_COMMITTER_EMAIL'::
 566 'GIT_COMMITTER_DATE'::
 567 'EMAIL'::
 568         see linkgit:git-commit-tree[1]
 569
 570 git Diffs
 571 ~~~~~~~~~
 572 'GIT_DIFF_OPTS'::
 573         Only valid setting is "--unified=??" or "-u??" to set the
 574         number of context lines shown when a unified diff is created.
 575         This takes precedence over any "-U" or "--unified" option
 576         value passed on the git diff command line.
 577
 578 'GIT_EXTERNAL_DIFF'::
 579         When the environment variable 'GIT_EXTERNAL_DIFF' is set, the
 580         program named by it is called, instead of the diff invocation
 581         described above.  For a path that is added, removed, or modified,
 582         'GIT_EXTERNAL_DIFF' is called with 7 parameters:
 583
 584         path old-file old-hex old-mode new-file new-hex new-mode
 585 +
 586 where:
 587
 588         <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the
 589                          contents of <old|new>,
 590         <old|new>-hex:: are the 40-hexdigit SHA1 hashes,
 591         <old|new>-mode:: are the octal representation of the file modes.
 592
 593 +
 594 The file parameters can point at the user's working file
 595 (e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
 596 when a new file is added), or a temporary file (e.g. `old-file` in the
 597 index).  'GIT_EXTERNAL_DIFF' should not worry about unlinking the
 598 temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits.
 599 +
 600 For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1
 601 parameter, <path>.
 602
 603 other
 604 ~~~~~
 605 'GIT_MERGE_VERBOSITY'::
 606         A number controlling the amount of output shown by
 607         the recursive merge strategy.  Overrides merge.verbosity.
 608         See linkgit:git-merge[1]
 609
 610 'GIT_PAGER'::
 611         This environment variable overrides `$PAGER`. If it is set
 612         to an empty string or to the value "cat", git will not launch
 613         a pager.  See also the `core.pager` option in
 614         linkgit:git-config[1].
 615
 616 'GIT_SSH'::
 617         If this environment variable is set then 'git fetch'
 618         and 'git push' will use this command instead
 619         of 'ssh' when they need to connect to a remote system.
 620         The '$GIT_SSH' command will be given exactly two arguments:
 621         the 'username@host' (or just 'host') from the URL and the
 622         shell command to execute on that remote system.
 623 +
 624 To pass options to the program that you want to list in GIT_SSH
 625 you will need to wrap the program and options into a shell script,
 626 then set GIT_SSH to refer to the shell script.
 627 +
 628 Usually it is easier to configure any desired options through your
 629 personal `.ssh/config` file.  Please consult your ssh documentation
 630 for further details.
 631
 632 'GIT_FLUSH'::
 633         If this environment variable is set to "1", then commands such
 634         as 'git blame' (in incremental mode), 'git rev-list', 'git log',
 635         and 'git whatchanged' will force a flush of the output stream
 636         after each commit-oriented record have been flushed.   If this
 637         variable is set to "0", the output of these commands will be done
 638         using completely buffered I/O.   If this environment variable is
 639         not set, git will choose buffered or record-oriented flushing
 640         based on whether stdout appears to be redirected to a file or not.
 641
 642 'GIT_TRACE'::
 643         If this variable is set to "1", "2" or "true" (comparison
 644         is case insensitive), git will print `trace:` messages on
 645         stderr telling about alias expansion, built-in command
 646         execution and external command execution.
 647         If this variable is set to an integer value greater than 1
 648         and lower than 10 (strictly) then git will interpret this
 649         value as an open file descriptor and will try to write the
 650         trace messages into this file descriptor.
 651         Alternatively, if this variable is set to an absolute path
 652         (starting with a '/' character), git will interpret this
 653         as a file path and will try to write the trace messages
 654         into it.
 655
 656 Discussion[[Discussion]]
 657 ------------------------
 658
 659 More detail on the following is available from the
 660 link:user-manual.html#git-concepts[git concepts chapter of the
 661 user-manual] and linkgit:gitcore-tutorial[7].
 662
 663 A git project normally consists of a working directory with a ".git"
 664 subdirectory at the top level.  The .git directory contains, among other
 665 things, a compressed object database representing the complete history
 666 of the project, an "index" file which links that history to the current
 667 contents of the working tree, and named pointers into that history such
 668 as tags and branch heads.
 669
 670 The object database contains objects of three main types: blobs, which
 671 hold file data; trees, which point to blobs and other trees to build up
 672 directory hierarchies; and commits, which each reference a single tree
 673 and some number of parent commits.
 674
 675 The commit, equivalent to what other systems call a "changeset" or
 676 "version", represents a step in the project's history, and each parent
 677 represents an immediately preceding step.  Commits with more than one
 678 parent represent merges of independent lines of development.
 679
 680 All objects are named by the SHA1 hash of their contents, normally
 681 written as a string of 40 hex digits.  Such names are globally unique.
 682 The entire history leading up to a commit can be vouched for by signing
 683 just that commit.  A fourth object type, the tag, is provided for this
 684 purpose.
 685
 686 When first created, objects are stored in individual files, but for
 687 efficiency may later be compressed together into "pack files".
 688
 689 Named pointers called refs mark interesting points in history.  A ref
 690 may contain the SHA1 name of an object or the name of another ref.  Refs
 691 with names beginning `ref/head/` contain the SHA1 name of the most
 692 recent commit (or "head") of a branch under development.  SHA1 names of
 693 tags of interest are stored under `ref/tags/`.  A special ref named
 694 `HEAD` contains the name of the currently checked-out branch.
 695
 696 The index file is initialized with a list of all paths and, for each
 697 path, a blob object and a set of attributes.  The blob object represents
 698 the contents of the file as of the head of the current branch.  The
 699 attributes (last modified time, size, etc.) are taken from the
 700 corresponding file in the working tree.  Subsequent changes to the
 701 working tree can be found by comparing these attributes.  The index may
 702 be updated with new content, and new commits may be created from the
 703 content stored in the index.
 704
 705 The index is also capable of storing multiple entries (called "stages")
 706 for a given pathname.  These stages are used to hold the various
 707 unmerged version of a file when a merge is in progress.
 708
 709 Authors
 710 -------
 711 * git's founding father is Linus Torvalds <torvalds@osdl.org>.
 712 * The current git nurse is Junio C Hamano <gitster@pobox.com>.
 713 * The git potty was written by Andreas Ericsson <ae@op5.se>.
 714 * General upbringing is handled by the git-list <git@vger.kernel.org>.
 715
 716 Documentation
 717 --------------
 718 The documentation for git suite was started by David Greaves
 719 <david@dgreaves.com>, and later enhanced greatly by the
 720 contributors on the git-list <git@vger.kernel.org>.
 721
 722 SEE ALSO
 723 --------
 724 linkgit:gittutorial[7], linkgit:gittutorial-2[7],
 725 link:everyday.html[Everyday Git], linkgit:gitcvs-migration[7],
 726 linkgit:gitglossary[7], linkgit:gitcore-tutorial[7],
 727 linkgit:gitcli[7], link:user-manual.html[The Git User's Manual],
 728 linkgit:gitworkflows[7]
 729
 730 GIT
 731 ---
 732 Part of the linkgit:git[1] suite