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]
  14     [--bare] [--git-dir=GIT_DIR] [--work-tree=GIT_WORK_TREE]
  15     [--help] COMMAND [ARGS]
  16
  17 DESCRIPTION
  18 -----------
  19 Git is a fast, scalable, distributed revision control system with an
  20 unusually rich command set that provides both high-level operations
  21 and full access to internals.
  22
  23 See linkgit:gittutorial[7] to get started, then see
  24 link:everyday.html[Everyday Git] for a useful minimum set of commands, and
  25 "man git-commandname" for documentation of each command.  CVS users may
  26 also want to read linkgit:gitcvs-migration[7].  See
  27 the link:user-manual.html[Git User's Manual] for a more in-depth
  28 introduction.
  29
  30 The COMMAND is either a name of a Git command (see below) or an alias
  31 as defined in the configuration file (see linkgit:git-config[1]).
  32
  33 Formatted and hyperlinked version of the latest git
  34 documentation can be viewed at
  35 `http://www.kernel.org/pub/software/scm/git/docs/`.
  36
  37 ifdef::stalenotes[]
  38 [NOTE]
  39 ============
  40
  41 You are reading the documentation for the latest (possibly
  42 unreleased) version of git, that is available from 'master'
  43 branch of the `git.git` repository.
  44 Documentation for older releases are available here:
  45
  46 * link:v1.6.5.4/git.html[documentation for release 1.6.5.4]
  47
  48 * release notes for
  49   link:RelNotes-1.6.5.4.txt[1.6.5.4],
  50   link:RelNotes-1.6.5.3.txt[1.6.5.3],
  51   link:RelNotes-1.6.5.2.txt[1.6.5.2],
  52   link:RelNotes-1.6.5.1.txt[1.6.5.1],
  53   link:RelNotes-1.6.5.txt[1.6.5].
  54
  55 * link:v1.6.4.4/git.html[documentation for release 1.6.4.4]
  56
  57 * release notes for
  58   link:RelNotes-1.6.4.4.txt[1.6.4.4],
  59   link:RelNotes-1.6.4.3.txt[1.6.4.3],
  60   link:RelNotes-1.6.4.2.txt[1.6.4.2],
  61   link:RelNotes-1.6.4.1.txt[1.6.4.1],
  62   link:RelNotes-1.6.4.txt[1.6.4].
  63
  64 * link:v1.6.3.4/git.html[documentation for release 1.6.3.4]
  65
  66 * release notes for
  67   link:RelNotes-1.6.3.4.txt[1.6.3.4],
  68   link:RelNotes-1.6.3.3.txt[1.6.3.3],
  69   link:RelNotes-1.6.3.2.txt[1.6.3.2],
  70   link:RelNotes-1.6.3.1.txt[1.6.3.1],
  71   link:RelNotes-1.6.3.txt[1.6.3].
  72
  73 * release notes for
  74   link:RelNotes-1.6.2.5.txt[1.6.2.5],
  75   link:RelNotes-1.6.2.4.txt[1.6.2.4],
  76   link:RelNotes-1.6.2.3.txt[1.6.2.3],
  77   link:RelNotes-1.6.2.2.txt[1.6.2.2],
  78   link:RelNotes-1.6.2.1.txt[1.6.2.1],
  79   link:RelNotes-1.6.2.txt[1.6.2].
  80
  81 * link:v1.6.1.3/git.html[documentation for release 1.6.1.3]
  82
  83 * release notes for
  84   link:RelNotes-1.6.1.3.txt[1.6.1.3],
  85   link:RelNotes-1.6.1.2.txt[1.6.1.2],
  86   link:RelNotes-1.6.1.1.txt[1.6.1.1],
  87   link:RelNotes-1.6.1.txt[1.6.1].
  88
  89 * link:v1.6.0.6/git.html[documentation for release 1.6.0.6]
  90
  91 * release notes for
  92   link:RelNotes-1.6.0.6.txt[1.6.0.6],
  93   link:RelNotes-1.6.0.5.txt[1.6.0.5],
  94   link:RelNotes-1.6.0.4.txt[1.6.0.4],
  95   link:RelNotes-1.6.0.3.txt[1.6.0.3],
  96   link:RelNotes-1.6.0.2.txt[1.6.0.2],
  97   link:RelNotes-1.6.0.1.txt[1.6.0.1],
  98   link:RelNotes-1.6.0.txt[1.6.0].
  99
 100 * link:v1.5.6.6/git.html[documentation for release 1.5.6.6]
 101
 102 * release notes for
 103   link:RelNotes-1.5.6.6.txt[1.5.6.6],
 104   link:RelNotes-1.5.6.5.txt[1.5.6.5],
 105   link:RelNotes-1.5.6.4.txt[1.5.6.4],
 106   link:RelNotes-1.5.6.3.txt[1.5.6.3],
 107   link:RelNotes-1.5.6.2.txt[1.5.6.2],
 108   link:RelNotes-1.5.6.1.txt[1.5.6.1],
 109   link:RelNotes-1.5.6.txt[1.5.6].
 110
 111 * link:v1.5.5.6/git.html[documentation for release 1.5.5.6]
 112
 113 * release notes for
 114   link:RelNotes-1.5.5.6.txt[1.5.5.6],
 115   link:RelNotes-1.5.5.5.txt[1.5.5.5],
 116   link:RelNotes-1.5.5.4.txt[1.5.5.4],
 117   link:RelNotes-1.5.5.3.txt[1.5.5.3],
 118   link:RelNotes-1.5.5.2.txt[1.5.5.2],
 119   link:RelNotes-1.5.5.1.txt[1.5.5.1],
 120   link:RelNotes-1.5.5.txt[1.5.5].
 121
 122 * link:v1.5.4.7/git.html[documentation for release 1.5.4.7]
 123
 124 * release notes for
 125   link:RelNotes-1.5.4.7.txt[1.5.4.7],
 126   link:RelNotes-1.5.4.6.txt[1.5.4.6],
 127   link:RelNotes-1.5.4.5.txt[1.5.4.5],
 128   link:RelNotes-1.5.4.4.txt[1.5.4.4],
 129   link:RelNotes-1.5.4.3.txt[1.5.4.3],
 130   link:RelNotes-1.5.4.2.txt[1.5.4.2],
 131   link:RelNotes-1.5.4.1.txt[1.5.4.1],
 132   link:RelNotes-1.5.4.txt[1.5.4].
 133
 134 * link:v1.5.3.8/git.html[documentation for release 1.5.3.8]
 135
 136 * release notes for
 137   link:RelNotes-1.5.3.8.txt[1.5.3.8],
 138   link:RelNotes-1.5.3.7.txt[1.5.3.7],
 139   link:RelNotes-1.5.3.6.txt[1.5.3.6],
 140   link:RelNotes-1.5.3.5.txt[1.5.3.5],
 141   link:RelNotes-1.5.3.4.txt[1.5.3.4],
 142   link:RelNotes-1.5.3.3.txt[1.5.3.3],
 143   link:RelNotes-1.5.3.2.txt[1.5.3.2],
 144   link:RelNotes-1.5.3.1.txt[1.5.3.1],
 145   link:RelNotes-1.5.3.txt[1.5.3].
 146
 147 * link:v1.5.2.5/git.html[documentation for release 1.5.2.5]
 148
 149 * release notes for
 150   link:RelNotes-1.5.2.5.txt[1.5.2.5],
 151   link:RelNotes-1.5.2.4.txt[1.5.2.4],
 152   link:RelNotes-1.5.2.3.txt[1.5.2.3],
 153   link:RelNotes-1.5.2.2.txt[1.5.2.2],
 154   link:RelNotes-1.5.2.1.txt[1.5.2.1],
 155   link:RelNotes-1.5.2.txt[1.5.2].
 156
 157 * link:v1.5.1.6/git.html[documentation for release 1.5.1.6]
 158
 159 * release notes for
 160   link:RelNotes-1.5.1.6.txt[1.5.1.6],
 161   link:RelNotes-1.5.1.5.txt[1.5.1.5],
 162   link:RelNotes-1.5.1.4.txt[1.5.1.4],
 163   link:RelNotes-1.5.1.3.txt[1.5.1.3],
 164   link:RelNotes-1.5.1.2.txt[1.5.1.2],
 165   link:RelNotes-1.5.1.1.txt[1.5.1.1],
 166   link:RelNotes-1.5.1.txt[1.5.1].
 167
 168 * link:v1.5.0.7/git.html[documentation for release 1.5.0.7]
 169
 170 * release notes for
 171   link:RelNotes-1.5.0.7.txt[1.5.0.7],
 172   link:RelNotes-1.5.0.6.txt[1.5.0.6],
 173   link:RelNotes-1.5.0.5.txt[1.5.0.5],
 174   link:RelNotes-1.5.0.3.txt[1.5.0.3],
 175   link:RelNotes-1.5.0.2.txt[1.5.0.2],
 176   link:RelNotes-1.5.0.1.txt[1.5.0.1],
 177   link:RelNotes-1.5.0.txt[1.5.0].
 178
 179 * documentation for release link:v1.4.4.4/git.html[1.4.4.4],
 180   link:v1.3.3/git.html[1.3.3],
 181   link:v1.2.6/git.html[1.2.6],
 182   link:v1.0.13/git.html[1.0.13].
 183
 184 ============
 185
 186 endif::stalenotes[]
 187
 188 OPTIONS
 189 -------
 190 --version::
 191         Prints the git suite version that the 'git' program came from.
 192
 193 --help::
 194         Prints the synopsis and a list of the most commonly used
 195         commands. If the option '--all' or '-a' is given then all
 196         available commands are printed. If a git command is named this
 197         option will bring up the manual page for that command.
 198 +
 199 Other options are available to control how the manual page is
 200 displayed. See linkgit:git-help[1] for more information,
 201 because `git --help ...` is converted internally into `git
 202 help ...`.
 203
 204 --exec-path::
 205         Path to wherever your core git programs are installed.
 206         This can also be controlled by setting the GIT_EXEC_PATH
 207         environment variable. If no path is given, 'git' will print
 208         the current setting and then exit.
 209
 210 --html-path::
 211         Print the path to wherever your git HTML documentation is installed
 212         and exit.
 213
 214 -p::
 215 --paginate::
 216         Pipe all output into 'less' (or if set, $PAGER).
 217
 218 --no-pager::
 219         Do not pipe git output into a pager.
 220
 221 --git-dir=<path>::
 222         Set the path to the repository. This can also be controlled by
 223         setting the GIT_DIR environment variable. It can be an absolute
 224         path or relative path to current working directory.
 225
 226 --work-tree=<path>::
 227         Set the path to the working tree.  The value will not be
 228         used in combination with repositories found automatically in
 229         a .git directory (i.e. $GIT_DIR is not set).
 230         This can also be controlled by setting the GIT_WORK_TREE
 231         environment variable and the core.worktree configuration
 232         variable. It can be an absolute path or relative path to
 233         the directory specified by --git-dir or GIT_DIR.
 234         Note: If --git-dir or GIT_DIR are specified but none of
 235         --work-tree, GIT_WORK_TREE and core.worktree is specified,
 236         the current working directory is regarded as the top directory
 237         of your working tree.
 238
 239 --bare::
 240         Treat the repository as a bare repository.  If GIT_DIR
 241         environment is not set, it is set to the current working
 242         directory.
 243
 244
 245 FURTHER DOCUMENTATION
 246 ---------------------
 247
 248 See the references above to get started using git.  The following is
 249 probably more detail than necessary for a first-time user.
 250
 251 The link:user-manual.html#git-concepts[git concepts chapter of the
 252 user-manual] and linkgit:gitcore-tutorial[7] both provide
 253 introductions to the underlying git architecture.
 254
 255 See linkgit:gitworkflows[7] for an overview of recommended workflows.
 256
 257 See also the link:howto-index.html[howto] documents for some useful
 258 examples.
 259
 260 The internals are documented in the
 261 link:technical/api-index.html[GIT API documentation].
 262
 263 GIT COMMANDS
 264 ------------
 265
 266 We divide git into high level ("porcelain") commands and low level
 267 ("plumbing") commands.
 268
 269 High-level commands (porcelain)
 270 -------------------------------
 271
 272 We separate the porcelain commands into the main commands and some
 273 ancillary user utilities.
 274
 275 Main porcelain commands
 276 ~~~~~~~~~~~~~~~~~~~~~~~
 277
 278 include::cmds-mainporcelain.txt[]
 279
 280 Ancillary Commands
 281 ~~~~~~~~~~~~~~~~~~
 282 Manipulators:
 283
 284 include::cmds-ancillarymanipulators.txt[]
 285
 286 Interrogators:
 287
 288 include::cmds-ancillaryinterrogators.txt[]
 289
 290
 291 Interacting with Others
 292 ~~~~~~~~~~~~~~~~~~~~~~~
 293
 294 These commands are to interact with foreign SCM and with other
 295 people via patch over e-mail.
 296
 297 include::cmds-foreignscminterface.txt[]
 298
 299
 300 Low-level commands (plumbing)
 301 -----------------------------
 302
 303 Although git includes its
 304 own porcelain layer, its low-level commands are sufficient to support
 305 development of alternative porcelains.  Developers of such porcelains
 306 might start by reading about linkgit:git-update-index[1] and
 307 linkgit:git-read-tree[1].
 308
 309 The interface (input, output, set of options and the semantics)
 310 to these low-level commands are meant to be a lot more stable
 311 than Porcelain level commands, because these commands are
 312 primarily for scripted use.  The interface to Porcelain commands
 313 on the other hand are subject to change in order to improve the
 314 end user experience.
 315
 316 The following description divides
 317 the low-level commands into commands that manipulate objects (in
 318 the repository, index, and working tree), commands that interrogate and
 319 compare objects, and commands that move objects and references between
 320 repositories.
 321
 322
 323 Manipulation commands
 324 ~~~~~~~~~~~~~~~~~~~~~
 325
 326 include::cmds-plumbingmanipulators.txt[]
 327
 328
 329 Interrogation commands
 330 ~~~~~~~~~~~~~~~~~~~~~~
 331
 332 include::cmds-plumbinginterrogators.txt[]
 333
 334 In general, the interrogate commands do not touch the files in
 335 the working tree.
 336
 337
 338 Synching repositories
 339 ~~~~~~~~~~~~~~~~~~~~~
 340
 341 include::cmds-synchingrepositories.txt[]
 342
 343 The following are helper commands used by the above; end users
 344 typically do not use them directly.
 345
 346 include::cmds-synchelpers.txt[]
 347
 348
 349 Internal helper commands
 350 ~~~~~~~~~~~~~~~~~~~~~~~~
 351
 352 These are internal helper commands used by other commands; end
 353 users typically do not use them directly.
 354
 355 include::cmds-purehelpers.txt[]
 356
 357
 358 Configuration Mechanism
 359 -----------------------
 360
 361 Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file
 362 is used to hold per-repository configuration options.  It is a
 363 simple text file modeled after `.ini` format familiar to some
 364 people.  Here is an example:
 365
 366 ------------
 367 #
 368 # A '#' or ';' character indicates a comment.
 369 #
 370
 371 ; core variables
 372 [core]
 373         ; Don't trust file modes
 374         filemode = false
 375
 376 ; user identity
 377 [user]
 378         name = "Junio C Hamano"
 379         email = "junkio@twinsun.com"
 380
 381 ------------
 382
 383 Various commands read from the configuration file and adjust
 384 their operation accordingly.
 385
 386
 387 Identifier Terminology
 388 ----------------------
 389 <object>::
 390         Indicates the object name for any type of object.
 391
 392 <blob>::
 393         Indicates a blob object name.
 394
 395 <tree>::
 396         Indicates a tree object name.
 397
 398 <commit>::
 399         Indicates a commit object name.
 400
 401 <tree-ish>::
 402         Indicates a tree, commit or tag object name.  A
 403         command that takes a <tree-ish> argument ultimately wants to
 404         operate on a <tree> object but automatically dereferences
 405         <commit> and <tag> objects that point at a <tree>.
 406
 407 <commit-ish>::
 408         Indicates a commit or tag object name.  A
 409         command that takes a <commit-ish> argument ultimately wants to
 410         operate on a <commit> object but automatically dereferences
 411         <tag> objects that point at a <commit>.
 412
 413 <type>::
 414         Indicates that an object type is required.
 415         Currently one of: `blob`, `tree`, `commit`, or `tag`.
 416
 417 <file>::
 418         Indicates a filename - almost always relative to the
 419         root of the tree structure `GIT_INDEX_FILE` describes.
 420
 421 Symbolic Identifiers
 422 --------------------
 423 Any git command accepting any <object> can also use the following
 424 symbolic notation:
 425
 426 HEAD::
 427         indicates the head of the current branch (i.e. the
 428         contents of `$GIT_DIR/HEAD`).
 429
 430 <tag>::
 431         a valid tag 'name'
 432         (i.e. the contents of `$GIT_DIR/refs/tags/<tag>`).
 433
 434 <head>::
 435         a valid head 'name'
 436         (i.e. the contents of `$GIT_DIR/refs/heads/<head>`).
 437
 438 For a more complete list of ways to spell object names, see
 439 "SPECIFYING REVISIONS" section in linkgit:git-rev-parse[1].
 440
 441
 442 File/Directory Structure
 443 ------------------------
 444
 445 Please see the linkgit:gitrepository-layout[5] document.
 446
 447 Read linkgit:githooks[5] for more details about each hook.
 448
 449 Higher level SCMs may provide and manage additional information in the
 450 `$GIT_DIR`.
 451
 452
 453 Terminology
 454 -----------
 455 Please see linkgit:gitglossary[7].
 456
 457
 458 Environment Variables
 459 ---------------------
 460 Various git commands use the following environment variables:
 461
 462 The git Repository
 463 ~~~~~~~~~~~~~~~~~~
 464 These environment variables apply to 'all' core git commands. Nb: it
 465 is worth noting that they may be used/overridden by SCMS sitting above
 466 git so take care if using Cogito etc.
 467
 468 'GIT_INDEX_FILE'::
 469         This environment allows the specification of an alternate
 470         index file. If not specified, the default of `$GIT_DIR/index`
 471         is used.
 472
 473 'GIT_OBJECT_DIRECTORY'::
 474         If the object storage directory is specified via this
 475         environment variable then the sha1 directories are created
 476         underneath - otherwise the default `$GIT_DIR/objects`
 477         directory is used.
 478
 479 'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
 480         Due to the immutable nature of git objects, old objects can be
 481         archived into shared, read-only directories. This variable
 482         specifies a ":" separated (on Windows ";" separated) list
 483         of git object directories which can be used to search for git
 484         objects. New objects will not be written to these directories.
 485
 486 'GIT_DIR'::
 487         If the 'GIT_DIR' environment variable is set then it
 488         specifies a path to use instead of the default `.git`
 489         for the base of the repository.
 490
 491 'GIT_WORK_TREE'::
 492         Set the path to the working tree.  The value will not be
 493         used in combination with repositories found automatically in
 494         a .git directory (i.e. $GIT_DIR is not set).
 495         This can also be controlled by the '--work-tree' command line
 496         option and the core.worktree configuration variable.
 497
 498 'GIT_CEILING_DIRECTORIES'::
 499         This should be a colon-separated list of absolute paths.
 500         If set, it is a list of directories that git should not chdir
 501         up into while looking for a repository directory.
 502         It will not exclude the current working directory or
 503         a GIT_DIR set on the command line or in the environment.
 504         (Useful for excluding slow-loading network directories.)
 505
 506 git Commits
 507 ~~~~~~~~~~~
 508 'GIT_AUTHOR_NAME'::
 509 'GIT_AUTHOR_EMAIL'::
 510 'GIT_AUTHOR_DATE'::
 511 'GIT_COMMITTER_NAME'::
 512 'GIT_COMMITTER_EMAIL'::
 513 'GIT_COMMITTER_DATE'::
 514 'EMAIL'::
 515         see linkgit:git-commit-tree[1]
 516
 517 git Diffs
 518 ~~~~~~~~~
 519 'GIT_DIFF_OPTS'::
 520         Only valid setting is "--unified=??" or "-u??" to set the
 521         number of context lines shown when a unified diff is created.
 522         This takes precedence over any "-U" or "--unified" option
 523         value passed on the git diff command line.
 524
 525 'GIT_EXTERNAL_DIFF'::
 526         When the environment variable 'GIT_EXTERNAL_DIFF' is set, the
 527         program named by it is called, instead of the diff invocation
 528         described above.  For a path that is added, removed, or modified,
 529         'GIT_EXTERNAL_DIFF' is called with 7 parameters:
 530
 531         path old-file old-hex old-mode new-file new-hex new-mode
 532 +
 533 where:
 534
 535         <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the
 536                          contents of <old|new>,
 537         <old|new>-hex:: are the 40-hexdigit SHA1 hashes,
 538         <old|new>-mode:: are the octal representation of the file modes.
 539
 540 +
 541 The file parameters can point at the user's working file
 542 (e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
 543 when a new file is added), or a temporary file (e.g. `old-file` in the
 544 index).  'GIT_EXTERNAL_DIFF' should not worry about unlinking the
 545 temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits.
 546 +
 547 For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1
 548 parameter, <path>.
 549
 550 other
 551 ~~~~~
 552 'GIT_MERGE_VERBOSITY'::
 553         A number controlling the amount of output shown by
 554         the recursive merge strategy.  Overrides merge.verbosity.
 555         See linkgit:git-merge[1]
 556
 557 'GIT_PAGER'::
 558         This environment variable overrides `$PAGER`. If it is set
 559         to an empty string or to the value "cat", git will not launch
 560         a pager.  See also the `core.pager` option in
 561         linkgit:git-config[1].
 562
 563 'GIT_SSH'::
 564         If this environment variable is set then 'git-fetch'
 565         and 'git-push' will use this command instead
 566         of 'ssh' when they need to connect to a remote system.
 567         The '$GIT_SSH' command will be given exactly two arguments:
 568         the 'username@host' (or just 'host') from the URL and the
 569         shell command to execute on that remote system.
 570 +
 571 To pass options to the program that you want to list in GIT_SSH
 572 you will need to wrap the program and options into a shell script,
 573 then set GIT_SSH to refer to the shell script.
 574 +
 575 Usually it is easier to configure any desired options through your
 576 personal `.ssh/config` file.  Please consult your ssh documentation
 577 for further details.
 578
 579 'GIT_FLUSH'::
 580         If this environment variable is set to "1", then commands such
 581         as 'git-blame' (in incremental mode), 'git-rev-list', 'git-log',
 582         and 'git-whatchanged' will force a flush of the output stream
 583         after each commit-oriented record have been flushed.   If this
 584         variable is set to "0", the output of these commands will be done
 585         using completely buffered I/O.   If this environment variable is
 586         not set, git will choose buffered or record-oriented flushing
 587         based on whether stdout appears to be redirected to a file or not.
 588
 589 'GIT_TRACE'::
 590         If this variable is set to "1", "2" or "true" (comparison
 591         is case insensitive), git will print `trace:` messages on
 592         stderr telling about alias expansion, built-in command
 593         execution and external command execution.
 594         If this variable is set to an integer value greater than 1
 595         and lower than 10 (strictly) then git will interpret this
 596         value as an open file descriptor and will try to write the
 597         trace messages into this file descriptor.
 598         Alternatively, if this variable is set to an absolute path
 599         (starting with a '/' character), git will interpret this
 600         as a file path and will try to write the trace messages
 601         into it.
 602
 603 Discussion[[Discussion]]
 604 ------------------------
 605
 606 More detail on the following is available from the
 607 link:user-manual.html#git-concepts[git concepts chapter of the
 608 user-manual] and linkgit:gitcore-tutorial[7].
 609
 610 A git project normally consists of a working directory with a ".git"
 611 subdirectory at the top level.  The .git directory contains, among other
 612 things, a compressed object database representing the complete history
 613 of the project, an "index" file which links that history to the current
 614 contents of the working tree, and named pointers into that history such
 615 as tags and branch heads.
 616
 617 The object database contains objects of three main types: blobs, which
 618 hold file data; trees, which point to blobs and other trees to build up
 619 directory hierarchies; and commits, which each reference a single tree
 620 and some number of parent commits.
 621
 622 The commit, equivalent to what other systems call a "changeset" or
 623 "version", represents a step in the project's history, and each parent
 624 represents an immediately preceding step.  Commits with more than one
 625 parent represent merges of independent lines of development.
 626
 627 All objects are named by the SHA1 hash of their contents, normally
 628 written as a string of 40 hex digits.  Such names are globally unique.
 629 The entire history leading up to a commit can be vouched for by signing
 630 just that commit.  A fourth object type, the tag, is provided for this
 631 purpose.
 632
 633 When first created, objects are stored in individual files, but for
 634 efficiency may later be compressed together into "pack files".
 635
 636 Named pointers called refs mark interesting points in history.  A ref
 637 may contain the SHA1 name of an object or the name of another ref.  Refs
 638 with names beginning `ref/head/` contain the SHA1 name of the most
 639 recent commit (or "head") of a branch under development.  SHA1 names of
 640 tags of interest are stored under `ref/tags/`.  A special ref named
 641 `HEAD` contains the name of the currently checked-out branch.
 642
 643 The index file is initialized with a list of all paths and, for each
 644 path, a blob object and a set of attributes.  The blob object represents
 645 the contents of the file as of the head of the current branch.  The
 646 attributes (last modified time, size, etc.) are taken from the
 647 corresponding file in the working tree.  Subsequent changes to the
 648 working tree can be found by comparing these attributes.  The index may
 649 be updated with new content, and new commits may be created from the
 650 content stored in the index.
 651
 652 The index is also capable of storing multiple entries (called "stages")
 653 for a given pathname.  These stages are used to hold the various
 654 unmerged version of a file when a merge is in progress.
 655
 656 Authors
 657 -------
 658 * git's founding father is Linus Torvalds <torvalds@osdl.org>.
 659 * The current git nurse is Junio C Hamano <gitster@pobox.com>.
 660 * The git potty was written by Andreas Ericsson <ae@op5.se>.
 661 * General upbringing is handled by the git-list <git@vger.kernel.org>.
 662
 663 Documentation
 664 --------------
 665 The documentation for git suite was started by David Greaves
 666 <david@dgreaves.com>, and later enhanced greatly by the
 667 contributors on the git-list <git@vger.kernel.org>.
 668
 669 SEE ALSO
 670 --------
 671 linkgit:gittutorial[7], linkgit:gittutorial-2[7],
 672 link:everyday.html[Everyday Git], linkgit:gitcvs-migration[7],
 673 linkgit:gitglossary[7], linkgit:gitcore-tutorial[7],
 674 linkgit:gitcli[7], link:user-manual.html[The Git User's Manual],
 675 linkgit:gitworkflows[7]
 676
 677 GIT
 678 ---
 679 Part of the linkgit:git[1] suite