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