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[=<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
  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:v1.7.4.4/git.html[documentation for release 1.7.4.4]
  48
  49 * release notes for
  50   link:RelNotes/1.7.4.4.txt[1.7.4.4],
  51   link:RelNotes/1.7.4.3.txt[1.7.4.3],
  52   link:RelNotes/1.7.4.2.txt[1.7.4.2],
  53   link:RelNotes/1.7.4.1.txt[1.7.4.1],
  54   link:RelNotes/1.7.4.txt[1.7.4].
  55
  56 * link:v1.7.3.5/git.html[documentation for release 1.7.3.5]
  57
  58 * release notes for
  59   link:RelNotes/1.7.3.5.txt[1.7.3.5],
  60   link:RelNotes/1.7.3.4.txt[1.7.3.4],
  61   link:RelNotes/1.7.3.3.txt[1.7.3.3],
  62   link:RelNotes/1.7.3.2.txt[1.7.3.2],
  63   link:RelNotes/1.7.3.1.txt[1.7.3.1],
  64   link:RelNotes/1.7.3.txt[1.7.3].
  65
  66 * link:v1.7.2.5/git.html[documentation for release 1.7.2.5]
  67
  68 * release notes for
  69   link:RelNotes/1.7.2.5.txt[1.7.2.5],
  70   link:RelNotes/1.7.2.4.txt[1.7.2.4],
  71   link:RelNotes/1.7.2.3.txt[1.7.2.3],
  72   link:RelNotes/1.7.2.2.txt[1.7.2.2],
  73   link:RelNotes/1.7.2.1.txt[1.7.2.1],
  74   link:RelNotes/1.7.2.txt[1.7.2].
  75
  76 * link:v1.7.1.4/git.html[documentation for release 1.7.1.4]
  77
  78 * release notes for
  79   link:RelNotes/1.7.1.4.txt[1.7.1.4],
  80   link:RelNotes/1.7.1.3.txt[1.7.1.3],
  81   link:RelNotes/1.7.1.2.txt[1.7.1.2],
  82   link:RelNotes/1.7.1.1.txt[1.7.1.1],
  83   link:RelNotes/1.7.1.txt[1.7.1].
  84
  85 * link:v1.7.0.9/git.html[documentation for release 1.7.0.9]
  86
  87 * release notes for
  88   link:RelNotes/1.7.0.9.txt[1.7.0.9],
  89   link:RelNotes/1.7.0.8.txt[1.7.0.8],
  90   link:RelNotes/1.7.0.7.txt[1.7.0.7],
  91   link:RelNotes/1.7.0.6.txt[1.7.0.6],
  92   link:RelNotes/1.7.0.5.txt[1.7.0.5],
  93   link:RelNotes/1.7.0.4.txt[1.7.0.4],
  94   link:RelNotes/1.7.0.3.txt[1.7.0.3],
  95   link:RelNotes/1.7.0.2.txt[1.7.0.2],
  96   link:RelNotes/1.7.0.1.txt[1.7.0.1],
  97   link:RelNotes/1.7.0.txt[1.7.0].
  98
  99 * link:v1.6.6.3/git.html[documentation for release 1.6.6.3]
 100
 101 * release notes for
 102   link:RelNotes/1.6.6.3.txt[1.6.6.3],
 103   link:RelNotes/1.6.6.2.txt[1.6.6.2],
 104   link:RelNotes/1.6.6.1.txt[1.6.6.1],
 105   link:RelNotes/1.6.6.txt[1.6.6].
 106
 107 * link:v1.6.5.9/git.html[documentation for release 1.6.5.9]
 108
 109 * release notes for
 110   link:RelNotes/1.6.5.9.txt[1.6.5.9],
 111   link:RelNotes/1.6.5.8.txt[1.6.5.8],
 112   link:RelNotes/1.6.5.7.txt[1.6.5.7],
 113   link:RelNotes/1.6.5.6.txt[1.6.5.6],
 114   link:RelNotes/1.6.5.5.txt[1.6.5.5],
 115   link:RelNotes/1.6.5.4.txt[1.6.5.4],
 116   link:RelNotes/1.6.5.3.txt[1.6.5.3],
 117   link:RelNotes/1.6.5.2.txt[1.6.5.2],
 118   link:RelNotes/1.6.5.1.txt[1.6.5.1],
 119   link:RelNotes/1.6.5.txt[1.6.5].
 120
 121 * link:v1.6.4.5/git.html[documentation for release 1.6.4.5]
 122
 123 * release notes for
 124   link:RelNotes/1.6.4.5.txt[1.6.4.5],
 125   link:RelNotes/1.6.4.4.txt[1.6.4.4],
 126   link:RelNotes/1.6.4.3.txt[1.6.4.3],
 127   link:RelNotes/1.6.4.2.txt[1.6.4.2],
 128   link:RelNotes/1.6.4.1.txt[1.6.4.1],
 129   link:RelNotes/1.6.4.txt[1.6.4].
 130
 131 * link:v1.6.3.4/git.html[documentation for release 1.6.3.4]
 132
 133 * release notes for
 134   link:RelNotes/1.6.3.4.txt[1.6.3.4],
 135   link:RelNotes/1.6.3.3.txt[1.6.3.3],
 136   link:RelNotes/1.6.3.2.txt[1.6.3.2],
 137   link:RelNotes/1.6.3.1.txt[1.6.3.1],
 138   link:RelNotes/1.6.3.txt[1.6.3].
 139
 140 * release notes for
 141   link:RelNotes/1.6.2.5.txt[1.6.2.5],
 142   link:RelNotes/1.6.2.4.txt[1.6.2.4],
 143   link:RelNotes/1.6.2.3.txt[1.6.2.3],
 144   link:RelNotes/1.6.2.2.txt[1.6.2.2],
 145   link:RelNotes/1.6.2.1.txt[1.6.2.1],
 146   link:RelNotes/1.6.2.txt[1.6.2].
 147
 148 * link:v1.6.1.3/git.html[documentation for release 1.6.1.3]
 149
 150 * release notes for
 151   link:RelNotes/1.6.1.3.txt[1.6.1.3],
 152   link:RelNotes/1.6.1.2.txt[1.6.1.2],
 153   link:RelNotes/1.6.1.1.txt[1.6.1.1],
 154   link:RelNotes/1.6.1.txt[1.6.1].
 155
 156 * link:v1.6.0.6/git.html[documentation for release 1.6.0.6]
 157
 158 * release notes for
 159   link:RelNotes/1.6.0.6.txt[1.6.0.6],
 160   link:RelNotes/1.6.0.5.txt[1.6.0.5],
 161   link:RelNotes/1.6.0.4.txt[1.6.0.4],
 162   link:RelNotes/1.6.0.3.txt[1.6.0.3],
 163   link:RelNotes/1.6.0.2.txt[1.6.0.2],
 164   link:RelNotes/1.6.0.1.txt[1.6.0.1],
 165   link:RelNotes/1.6.0.txt[1.6.0].
 166
 167 * link:v1.5.6.6/git.html[documentation for release 1.5.6.6]
 168
 169 * release notes for
 170   link:RelNotes/1.5.6.6.txt[1.5.6.6],
 171   link:RelNotes/1.5.6.5.txt[1.5.6.5],
 172   link:RelNotes/1.5.6.4.txt[1.5.6.4],
 173   link:RelNotes/1.5.6.3.txt[1.5.6.3],
 174   link:RelNotes/1.5.6.2.txt[1.5.6.2],
 175   link:RelNotes/1.5.6.1.txt[1.5.6.1],
 176   link:RelNotes/1.5.6.txt[1.5.6].
 177
 178 * link:v1.5.5.6/git.html[documentation for release 1.5.5.6]
 179
 180 * release notes for
 181   link:RelNotes/1.5.5.6.txt[1.5.5.6],
 182   link:RelNotes/1.5.5.5.txt[1.5.5.5],
 183   link:RelNotes/1.5.5.4.txt[1.5.5.4],
 184   link:RelNotes/1.5.5.3.txt[1.5.5.3],
 185   link:RelNotes/1.5.5.2.txt[1.5.5.2],
 186   link:RelNotes/1.5.5.1.txt[1.5.5.1],
 187   link:RelNotes/1.5.5.txt[1.5.5].
 188
 189 * link:v1.5.4.7/git.html[documentation for release 1.5.4.7]
 190
 191 * release notes for
 192   link:RelNotes/1.5.4.7.txt[1.5.4.7],
 193   link:RelNotes/1.5.4.6.txt[1.5.4.6],
 194   link:RelNotes/1.5.4.5.txt[1.5.4.5],
 195   link:RelNotes/1.5.4.4.txt[1.5.4.4],
 196   link:RelNotes/1.5.4.3.txt[1.5.4.3],
 197   link:RelNotes/1.5.4.2.txt[1.5.4.2],
 198   link:RelNotes/1.5.4.1.txt[1.5.4.1],
 199   link:RelNotes/1.5.4.txt[1.5.4].
 200
 201 * link:v1.5.3.8/git.html[documentation for release 1.5.3.8]
 202
 203 * release notes for
 204   link:RelNotes/1.5.3.8.txt[1.5.3.8],
 205   link:RelNotes/1.5.3.7.txt[1.5.3.7],
 206   link:RelNotes/1.5.3.6.txt[1.5.3.6],
 207   link:RelNotes/1.5.3.5.txt[1.5.3.5],
 208   link:RelNotes/1.5.3.4.txt[1.5.3.4],
 209   link:RelNotes/1.5.3.3.txt[1.5.3.3],
 210   link:RelNotes/1.5.3.2.txt[1.5.3.2],
 211   link:RelNotes/1.5.3.1.txt[1.5.3.1],
 212   link:RelNotes/1.5.3.txt[1.5.3].
 213
 214 * link:v1.5.2.5/git.html[documentation for release 1.5.2.5]
 215
 216 * release notes for
 217   link:RelNotes/1.5.2.5.txt[1.5.2.5],
 218   link:RelNotes/1.5.2.4.txt[1.5.2.4],
 219   link:RelNotes/1.5.2.3.txt[1.5.2.3],
 220   link:RelNotes/1.5.2.2.txt[1.5.2.2],
 221   link:RelNotes/1.5.2.1.txt[1.5.2.1],
 222   link:RelNotes/1.5.2.txt[1.5.2].
 223
 224 * link:v1.5.1.6/git.html[documentation for release 1.5.1.6]
 225
 226 * release notes for
 227   link:RelNotes/1.5.1.6.txt[1.5.1.6],
 228   link:RelNotes/1.5.1.5.txt[1.5.1.5],
 229   link:RelNotes/1.5.1.4.txt[1.5.1.4],
 230   link:RelNotes/1.5.1.3.txt[1.5.1.3],
 231   link:RelNotes/1.5.1.2.txt[1.5.1.2],
 232   link:RelNotes/1.5.1.1.txt[1.5.1.1],
 233   link:RelNotes/1.5.1.txt[1.5.1].
 234
 235 * link:v1.5.0.7/git.html[documentation for release 1.5.0.7]
 236
 237 * release notes for
 238   link:RelNotes/1.5.0.7.txt[1.5.0.7],
 239   link:RelNotes/1.5.0.6.txt[1.5.0.6],
 240   link:RelNotes/1.5.0.5.txt[1.5.0.5],
 241   link:RelNotes/1.5.0.3.txt[1.5.0.3],
 242   link:RelNotes/1.5.0.2.txt[1.5.0.2],
 243   link:RelNotes/1.5.0.1.txt[1.5.0.1],
 244   link:RelNotes/1.5.0.txt[1.5.0].
 245
 246 * documentation for release link:v1.4.4.4/git.html[1.4.4.4],
 247   link:v1.3.3/git.html[1.3.3],
 248   link:v1.2.6/git.html[1.2.6],
 249   link:v1.0.13/git.html[1.0.13].
 250
 251 ============
 252
 253 endif::stalenotes[]
 254
 255 OPTIONS
 256 -------
 257 --version::
 258         Prints the git suite version that the 'git' program came from.
 259
 260 --help::
 261         Prints the synopsis and a list of the most commonly used
 262         commands. If the option '--all' or '-a' is given then all
 263         available commands are printed. If a git command is named this
 264         option will bring up the manual page for that command.
 265 +
 266 Other options are available to control how the manual page is
 267 displayed. See linkgit:git-help[1] for more information,
 268 because `git --help ...` is converted internally into `git
 269 help ...`.
 270
 271 -c <name>=<value>::
 272         Pass a configuration parameter to the command. The value
 273         given will override values from configuration files.
 274         The <name> is expected in the same format as listed by
 275         'git config' (subkeys separated by dots).
 276
 277 --exec-path[=<path>]::
 278         Path to wherever your core git programs are installed.
 279         This can also be controlled by setting the GIT_EXEC_PATH
 280         environment variable. If no path is given, 'git' will print
 281         the current setting and then exit.
 282
 283 --html-path::
 284         Print the path to wherever your git HTML documentation is installed
 285         and exit.
 286
 287 -p::
 288 --paginate::
 289         Pipe all output into 'less' (or if set, $PAGER) if standard
 290         output is a terminal.  This overrides the `pager.<cmd>`
 291         configuration options (see the "Configuration Mechanism" section
 292         below).
 293
 294 --no-pager::
 295         Do not pipe git output into a pager.
 296
 297 --git-dir=<path>::
 298         Set the path to the repository. This can also be controlled by
 299         setting the GIT_DIR environment variable. It can be an absolute
 300         path or relative path to current working directory.
 301
 302 --work-tree=<path>::
 303         Set the path to the working tree. It can be an absolute path
 304         or a path relative to the current working directory.
 305         This can also be controlled by setting the GIT_WORK_TREE
 306         environment variable and the core.worktree configuration
 307         variable (see core.worktree in linkgit:git-config[1] for a
 308         more detailed discussion).
 309
 310 --bare::
 311         Treat the repository as a bare repository.  If GIT_DIR
 312         environment is not set, it is set to the current working
 313         directory.
 314
 315 --no-replace-objects::
 316         Do not use replacement refs to replace git objects. See
 317         linkgit:git-replace[1] for more information.
 318
 319
 320 FURTHER DOCUMENTATION
 321 ---------------------
 322
 323 See the references above to get started using git.  The following is
 324 probably more detail than necessary for a first-time user.
 325
 326 The link:user-manual.html#git-concepts[git concepts chapter of the
 327 user-manual] and linkgit:gitcore-tutorial[7] both provide
 328 introductions to the underlying git architecture.
 329
 330 See linkgit:gitworkflows[7] for an overview of recommended workflows.
 331
 332 See also the link:howto-index.html[howto] documents for some useful
 333 examples.
 334
 335 The internals are documented in the
 336 link:technical/api-index.html[GIT API documentation].
 337
 338 GIT COMMANDS
 339 ------------
 340
 341 We divide git into high level ("porcelain") commands and low level
 342 ("plumbing") commands.
 343
 344 High-level commands (porcelain)
 345 -------------------------------
 346
 347 We separate the porcelain commands into the main commands and some
 348 ancillary user utilities.
 349
 350 Main porcelain commands
 351 ~~~~~~~~~~~~~~~~~~~~~~~
 352
 353 include::cmds-mainporcelain.txt[]
 354
 355 Ancillary Commands
 356 ~~~~~~~~~~~~~~~~~~
 357 Manipulators:
 358
 359 include::cmds-ancillarymanipulators.txt[]
 360
 361 Interrogators:
 362
 363 include::cmds-ancillaryinterrogators.txt[]
 364
 365
 366 Interacting with Others
 367 ~~~~~~~~~~~~~~~~~~~~~~~
 368
 369 These commands are to interact with foreign SCM and with other
 370 people via patch over e-mail.
 371
 372 include::cmds-foreignscminterface.txt[]
 373
 374
 375 Low-level commands (plumbing)
 376 -----------------------------
 377
 378 Although git includes its
 379 own porcelain layer, its low-level commands are sufficient to support
 380 development of alternative porcelains.  Developers of such porcelains
 381 might start by reading about linkgit:git-update-index[1] and
 382 linkgit:git-read-tree[1].
 383
 384 The interface (input, output, set of options and the semantics)
 385 to these low-level commands are meant to be a lot more stable
 386 than Porcelain level commands, because these commands are
 387 primarily for scripted use.  The interface to Porcelain commands
 388 on the other hand are subject to change in order to improve the
 389 end user experience.
 390
 391 The following description divides
 392 the low-level commands into commands that manipulate objects (in
 393 the repository, index, and working tree), commands that interrogate and
 394 compare objects, and commands that move objects and references between
 395 repositories.
 396
 397
 398 Manipulation commands
 399 ~~~~~~~~~~~~~~~~~~~~~
 400
 401 include::cmds-plumbingmanipulators.txt[]
 402
 403
 404 Interrogation commands
 405 ~~~~~~~~~~~~~~~~~~~~~~
 406
 407 include::cmds-plumbinginterrogators.txt[]
 408
 409 In general, the interrogate commands do not touch the files in
 410 the working tree.
 411
 412
 413 Synching repositories
 414 ~~~~~~~~~~~~~~~~~~~~~
 415
 416 include::cmds-synchingrepositories.txt[]
 417
 418 The following are helper commands used by the above; end users
 419 typically do not use them directly.
 420
 421 include::cmds-synchelpers.txt[]
 422
 423
 424 Internal helper commands
 425 ~~~~~~~~~~~~~~~~~~~~~~~~
 426
 427 These are internal helper commands used by other commands; end
 428 users typically do not use them directly.
 429
 430 include::cmds-purehelpers.txt[]
 431
 432
 433 Configuration Mechanism
 434 -----------------------
 435
 436 Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file
 437 is used to hold per-repository configuration options.  It is a
 438 simple text file modeled after `.ini` format familiar to some
 439 people.  Here is an example:
 440
 441 ------------
 442 #
 443 # A '#' or ';' character indicates a comment.
 444 #
 445
 446 ; core variables
 447 [core]
 448         ; Don't trust file modes
 449         filemode = false
 450
 451 ; user identity
 452 [user]
 453         name = "Junio C Hamano"
 454         email = "junkio@twinsun.com"
 455
 456 ------------
 457
 458 Various commands read from the configuration file and adjust
 459 their operation accordingly.  See linkgit:git-config[1] for a
 460 list.
 461
 462
 463 Identifier Terminology
 464 ----------------------
 465 <object>::
 466         Indicates the object name for any type of object.
 467
 468 <blob>::
 469         Indicates a blob object name.
 470
 471 <tree>::
 472         Indicates a tree object name.
 473
 474 <commit>::
 475         Indicates a commit object name.
 476
 477 <tree-ish>::
 478         Indicates a tree, commit or tag object name.  A
 479         command that takes a <tree-ish> argument ultimately wants to
 480         operate on a <tree> object but automatically dereferences
 481         <commit> and <tag> objects that point at a <tree>.
 482
 483 <commit-ish>::
 484         Indicates a commit or tag object name.  A
 485         command that takes a <commit-ish> argument ultimately wants to
 486         operate on a <commit> object but automatically dereferences
 487         <tag> objects that point at a <commit>.
 488
 489 <type>::
 490         Indicates that an object type is required.
 491         Currently one of: `blob`, `tree`, `commit`, or `tag`.
 492
 493 <file>::
 494         Indicates a filename - almost always relative to the
 495         root of the tree structure `GIT_INDEX_FILE` describes.
 496
 497 Symbolic Identifiers
 498 --------------------
 499 Any git command accepting any <object> can also use the following
 500 symbolic notation:
 501
 502 HEAD::
 503         indicates the head of the current branch (i.e. the
 504         contents of `$GIT_DIR/HEAD`).
 505
 506 <tag>::
 507         a valid tag 'name'
 508         (i.e. the contents of `$GIT_DIR/refs/tags/<tag>`).
 509
 510 <head>::
 511         a valid head 'name'
 512         (i.e. the contents of `$GIT_DIR/refs/heads/<head>`).
 513
 514 For a more complete list of ways to spell object names, see
 515 "SPECIFYING REVISIONS" section in linkgit:gitrevisions[7].
 516
 517
 518 File/Directory Structure
 519 ------------------------
 520
 521 Please see the linkgit:gitrepository-layout[5] document.
 522
 523 Read linkgit:githooks[5] for more details about each hook.
 524
 525 Higher level SCMs may provide and manage additional information in the
 526 `$GIT_DIR`.
 527
 528
 529 Terminology
 530 -----------
 531 Please see linkgit:gitglossary[7].
 532
 533
 534 Environment Variables
 535 ---------------------
 536 Various git commands use the following environment variables:
 537
 538 The git Repository
 539 ~~~~~~~~~~~~~~~~~~
 540 These environment variables apply to 'all' core git commands. Nb: it
 541 is worth noting that they may be used/overridden by SCMS sitting above
 542 git so take care if using Cogito etc.
 543
 544 'GIT_INDEX_FILE'::
 545         This environment allows the specification of an alternate
 546         index file. If not specified, the default of `$GIT_DIR/index`
 547         is used.
 548
 549 'GIT_OBJECT_DIRECTORY'::
 550         If the object storage directory is specified via this
 551         environment variable then the sha1 directories are created
 552         underneath - otherwise the default `$GIT_DIR/objects`
 553         directory is used.
 554
 555 'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
 556         Due to the immutable nature of git objects, old objects can be
 557         archived into shared, read-only directories. This variable
 558         specifies a ":" separated (on Windows ";" separated) list
 559         of git object directories which can be used to search for git
 560         objects. New objects will not be written to these directories.
 561
 562 'GIT_DIR'::
 563         If the 'GIT_DIR' environment variable is set then it
 564         specifies a path to use instead of the default `.git`
 565         for the base of the repository.
 566
 567 'GIT_WORK_TREE'::
 568         Set the path to the working tree.  The value will not be
 569         used in combination with repositories found automatically in
 570         a .git directory (i.e. $GIT_DIR is not set).
 571         This can also be controlled by the '--work-tree' command line
 572         option and the core.worktree configuration variable.
 573
 574 'GIT_CEILING_DIRECTORIES'::
 575         This should be a colon-separated list of absolute paths.
 576         If set, it is a list of directories that git should not chdir
 577         up into while looking for a repository directory.
 578         It will not exclude the current working directory or
 579         a GIT_DIR set on the command line or in the environment.
 580         (Useful for excluding slow-loading network directories.)
 581
 582 'GIT_DISCOVERY_ACROSS_FILESYSTEM'::
 583         When run in a directory that does not have ".git" repository
 584         directory, git tries to find such a directory in the parent
 585         directories to find the top of the working tree, but by default it
 586         does not cross filesystem boundaries.  This environment variable
 587         can be set to true to tell git not to stop at filesystem
 588         boundaries.  Like 'GIT_CEILING_DIRECTORIES', this will not affect
 589         an explicit repository directory set via 'GIT_DIR' or on the
 590         command line.
 591
 592 git Commits
 593 ~~~~~~~~~~~
 594 'GIT_AUTHOR_NAME'::
 595 'GIT_AUTHOR_EMAIL'::
 596 'GIT_AUTHOR_DATE'::
 597 'GIT_COMMITTER_NAME'::
 598 'GIT_COMMITTER_EMAIL'::
 599 'GIT_COMMITTER_DATE'::
 600 'EMAIL'::
 601         see linkgit:git-commit-tree[1]
 602
 603 git Diffs
 604 ~~~~~~~~~
 605 'GIT_DIFF_OPTS'::
 606         Only valid setting is "--unified=??" or "-u??" to set the
 607         number of context lines shown when a unified diff is created.
 608         This takes precedence over any "-U" or "--unified" option
 609         value passed on the git diff command line.
 610
 611 'GIT_EXTERNAL_DIFF'::
 612         When the environment variable 'GIT_EXTERNAL_DIFF' is set, the
 613         program named by it is called, instead of the diff invocation
 614         described above.  For a path that is added, removed, or modified,
 615         'GIT_EXTERNAL_DIFF' is called with 7 parameters:
 616
 617         path old-file old-hex old-mode new-file new-hex new-mode
 618 +
 619 where:
 620
 621         <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the
 622                          contents of <old|new>,
 623         <old|new>-hex:: are the 40-hexdigit SHA1 hashes,
 624         <old|new>-mode:: are the octal representation of the file modes.
 625
 626 +
 627 The file parameters can point at the user's working file
 628 (e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
 629 when a new file is added), or a temporary file (e.g. `old-file` in the
 630 index).  'GIT_EXTERNAL_DIFF' should not worry about unlinking the
 631 temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits.
 632 +
 633 For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1
 634 parameter, <path>.
 635
 636 other
 637 ~~~~~
 638 'GIT_MERGE_VERBOSITY'::
 639         A number controlling the amount of output shown by
 640         the recursive merge strategy.  Overrides merge.verbosity.
 641         See linkgit:git-merge[1]
 642
 643 'GIT_PAGER'::
 644         This environment variable overrides `$PAGER`. If it is set
 645         to an empty string or to the value "cat", git will not launch
 646         a pager.  See also the `core.pager` option in
 647         linkgit:git-config[1].
 648
 649 'GIT_SSH'::
 650         If this environment variable is set then 'git fetch'
 651         and 'git push' will use this command instead
 652         of 'ssh' when they need to connect to a remote system.
 653         The '$GIT_SSH' command will be given exactly two arguments:
 654         the 'username@host' (or just 'host') from the URL and the
 655         shell command to execute on that remote system.
 656 +
 657 To pass options to the program that you want to list in GIT_SSH
 658 you will need to wrap the program and options into a shell script,
 659 then set GIT_SSH to refer to the shell script.
 660 +
 661 Usually it is easier to configure any desired options through your
 662 personal `.ssh/config` file.  Please consult your ssh documentation
 663 for further details.
 664
 665 'GIT_ASKPASS'::
 666         If this environment variable is set, then git commands which need to
 667         acquire passwords or passphrases (e.g. for HTTP or IMAP authentication)
 668         will call this program with a suitable prompt as command line argument
 669         and read the password from its STDOUT. See also the 'core.askpass'
 670         option in linkgit:git-config[1].
 671
 672 'GIT_FLUSH'::
 673         If this environment variable is set to "1", then commands such
 674         as 'git blame' (in incremental mode), 'git rev-list', 'git log',
 675         and 'git whatchanged' will force a flush of the output stream
 676         after each commit-oriented record have been flushed.   If this
 677         variable is set to "0", the output of these commands will be done
 678         using completely buffered I/O.   If this environment variable is
 679         not set, git will choose buffered or record-oriented flushing
 680         based on whether stdout appears to be redirected to a file or not.
 681
 682 'GIT_TRACE'::
 683         If this variable is set to "1", "2" or "true" (comparison
 684         is case insensitive), git will print `trace:` messages on
 685         stderr telling about alias expansion, built-in command
 686         execution and external command execution.
 687         If this variable is set to an integer value greater than 1
 688         and lower than 10 (strictly) then git will interpret this
 689         value as an open file descriptor and will try to write the
 690         trace messages into this file descriptor.
 691         Alternatively, if this variable is set to an absolute path
 692         (starting with a '/' character), git will interpret this
 693         as a file path and will try to write the trace messages
 694         into it.
 695
 696 Discussion[[Discussion]]
 697 ------------------------
 698
 699 More detail on the following is available from the
 700 link:user-manual.html#git-concepts[git concepts chapter of the
 701 user-manual] and linkgit:gitcore-tutorial[7].
 702
 703 A git project normally consists of a working directory with a ".git"
 704 subdirectory at the top level.  The .git directory contains, among other
 705 things, a compressed object database representing the complete history
 706 of the project, an "index" file which links that history to the current
 707 contents of the working tree, and named pointers into that history such
 708 as tags and branch heads.
 709
 710 The object database contains objects of three main types: blobs, which
 711 hold file data; trees, which point to blobs and other trees to build up
 712 directory hierarchies; and commits, which each reference a single tree
 713 and some number of parent commits.
 714
 715 The commit, equivalent to what other systems call a "changeset" or
 716 "version", represents a step in the project's history, and each parent
 717 represents an immediately preceding step.  Commits with more than one
 718 parent represent merges of independent lines of development.
 719
 720 All objects are named by the SHA1 hash of their contents, normally
 721 written as a string of 40 hex digits.  Such names are globally unique.
 722 The entire history leading up to a commit can be vouched for by signing
 723 just that commit.  A fourth object type, the tag, is provided for this
 724 purpose.
 725
 726 When first created, objects are stored in individual files, but for
 727 efficiency may later be compressed together into "pack files".
 728
 729 Named pointers called refs mark interesting points in history.  A ref
 730 may contain the SHA1 name of an object or the name of another ref.  Refs
 731 with names beginning `ref/head/` contain the SHA1 name of the most
 732 recent commit (or "head") of a branch under development.  SHA1 names of
 733 tags of interest are stored under `ref/tags/`.  A special ref named
 734 `HEAD` contains the name of the currently checked-out branch.
 735
 736 The index file is initialized with a list of all paths and, for each
 737 path, a blob object and a set of attributes.  The blob object represents
 738 the contents of the file as of the head of the current branch.  The
 739 attributes (last modified time, size, etc.) are taken from the
 740 corresponding file in the working tree.  Subsequent changes to the
 741 working tree can be found by comparing these attributes.  The index may
 742 be updated with new content, and new commits may be created from the
 743 content stored in the index.
 744
 745 The index is also capable of storing multiple entries (called "stages")
 746 for a given pathname.  These stages are used to hold the various
 747 unmerged version of a file when a merge is in progress.
 748
 749 Authors
 750 -------
 751 Git was started by Linus Torvalds, and is currently maintained by Junio
 752 C Hamano. Numerous contributions have come from the git mailing list
 753 <git@vger.kernel.org>. For a more complete list of contributors, see
 754 http://git-scm.com/about. If you have a clone of git.git itself, the
 755 output of linkgit:git-shortlog[1] and linkgit:git-blame[1] can show you
 756 the authors for specific parts of the project.
 757
 758 Reporting Bugs
 759 --------------
 760
 761 Report bugs to the Git mailing list <git@vger.kernel.org> where the
 762 development and maintenance is primarily done.  You do not have to be
 763 subscribed to the list to send a message there.
 764
 765 SEE ALSO
 766 --------
 767 linkgit:gittutorial[7], linkgit:gittutorial-2[7],
 768 link:everyday.html[Everyday Git], linkgit:gitcvs-migration[7],
 769 linkgit:gitglossary[7], linkgit:gitcore-tutorial[7],
 770 linkgit:gitcli[7], link:user-manual.html[The Git User's Manual],
 771 linkgit:gitworkflows[7]
 772
 773 GIT
 774 ---
 775 Part of the linkgit:git[1] suite