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