Documentation/git.txt

   1 git(1)
   2 ======
   3
   4 NAME
   5 ----
   6 git - the stupid content tracker
   7
   8
   9 SYNOPSIS
  10 --------
  11 [verse]
  12 'git' [--version] [--exec-path[=GIT_EXEC_PATH]] [--html-path]
  13     [-p|--paginate|--no-pager] [--no-replace-objects]
  14     [--bare] [--git-dir=GIT_DIR] [--work-tree=GIT_WORK_TREE]
  15     [-c name=value]
  16     [--help] COMMAND [ARGS]
  17
  18 DESCRIPTION
  19 -----------
  20 Git is a fast, scalable, distributed revision control system with an
  21 unusually rich command set that provides both high-level operations
  22 and full access to internals.
  23
  24 See linkgit:gittutorial[7] to get started, then see
  25 link:everyday.html[Everyday Git] for a useful minimum set of commands, and
  26 "man git-commandname" for documentation of each command.  CVS users may
  27 also want to read linkgit:gitcvs-migration[7].  See
  28 the link:user-manual.html[Git User's Manual] for a more in-depth
  29 introduction.
  30
  31 The COMMAND is either a name of a Git command (see below) or an alias
  32 as defined in the configuration file (see linkgit:git-config[1]).
  33
  34 Formatted and hyperlinked version of the latest git
  35 documentation can be viewed at
  36 `http://www.kernel.org/pub/software/scm/git/docs/`.
  37
  38 ifdef::stalenotes[]
  39 [NOTE]
  40 ============
  41
  42 You are reading the documentation for the latest (possibly
  43 unreleased) version of git, that is available from 'master'
  44 branch of the `git.git` repository.
  45 Documentation for older releases are available here:
  46
  47 * link:v1.7.1/git.html[documentation for release 1.7.1]
  48
  49 * release notes for
  50   link:RelNotes-1.7.1.txt[1.7.1].
  51
  52 * link:v1.7.0.6/git.html[documentation for release 1.7.0.6]
  53
  54 * release notes for
  55   link:RelNotes-1.7.0.6.txt[1.7.0.6],
  56   link:RelNotes-1.7.0.5.txt[1.7.0.5],
  57   link:RelNotes-1.7.0.4.txt[1.7.0.4],
  58   link:RelNotes-1.7.0.3.txt[1.7.0.3],
  59   link:RelNotes-1.7.0.2.txt[1.7.0.2],
  60   link:RelNotes-1.7.0.1.txt[1.7.0.1],
  61   link:RelNotes-1.7.0.txt[1.7.0].
  62
  63 * link:v1.6.6.2/git.html[documentation for release 1.6.6.2]
  64
  65 * release notes for
  66   link:RelNotes-1.6.6.2.txt[1.6.6.2],
  67   link:RelNotes-1.6.6.1.txt[1.6.6.1],
  68   link:RelNotes-1.6.6.txt[1.6.6].
  69
  70 * link:v1.6.5.8/git.html[documentation for release 1.6.5.8]
  71
  72 * release notes for
  73   link:RelNotes-1.6.5.8.txt[1.6.5.8],
  74   link:RelNotes-1.6.5.7.txt[1.6.5.7],
  75   link:RelNotes-1.6.5.6.txt[1.6.5.6],
  76   link:RelNotes-1.6.5.5.txt[1.6.5.5],
  77   link:RelNotes-1.6.5.4.txt[1.6.5.4],
  78   link:RelNotes-1.6.5.3.txt[1.6.5.3],
  79   link:RelNotes-1.6.5.2.txt[1.6.5.2],
  80   link:RelNotes-1.6.5.1.txt[1.6.5.1],
  81   link:RelNotes-1.6.5.txt[1.6.5].
  82
  83 * link:v1.6.4.4/git.html[documentation for release 1.6.4.4]
  84
  85 * release notes for
  86   link:RelNotes-1.6.4.4.txt[1.6.4.4],
  87   link:RelNotes-1.6.4.3.txt[1.6.4.3],
  88   link:RelNotes-1.6.4.2.txt[1.6.4.2],
  89   link:RelNotes-1.6.4.1.txt[1.6.4.1],
  90   link:RelNotes-1.6.4.txt[1.6.4].
  91
  92 * link:v1.6.3.4/git.html[documentation for release 1.6.3.4]
  93
  94 * release notes for
  95   link:RelNotes-1.6.3.4.txt[1.6.3.4],
  96   link:RelNotes-1.6.3.3.txt[1.6.3.3],
  97   link:RelNotes-1.6.3.2.txt[1.6.3.2],
  98   link:RelNotes-1.6.3.1.txt[1.6.3.1],
  99   link:RelNotes-1.6.3.txt[1.6.3].
 100
 101 * release notes for
 102   link:RelNotes-1.6.2.5.txt[1.6.2.5],
 103   link:RelNotes-1.6.2.4.txt[1.6.2.4],
 104   link:RelNotes-1.6.2.3.txt[1.6.2.3],
 105   link:RelNotes-1.6.2.2.txt[1.6.2.2],
 106   link:RelNotes-1.6.2.1.txt[1.6.2.1],
 107   link:RelNotes-1.6.2.txt[1.6.2].
 108
 109 * link:v1.6.1.3/git.html[documentation for release 1.6.1.3]
 110
 111 * release notes for
 112   link:RelNotes-1.6.1.3.txt[1.6.1.3],
 113   link:RelNotes-1.6.1.2.txt[1.6.1.2],
 114   link:RelNotes-1.6.1.1.txt[1.6.1.1],
 115   link:RelNotes-1.6.1.txt[1.6.1].
 116
 117 * link:v1.6.0.6/git.html[documentation for release 1.6.0.6]
 118
 119 * release notes for
 120   link:RelNotes-1.6.0.6.txt[1.6.0.6],
 121   link:RelNotes-1.6.0.5.txt[1.6.0.5],
 122   link:RelNotes-1.6.0.4.txt[1.6.0.4],
 123   link:RelNotes-1.6.0.3.txt[1.6.0.3],
 124   link:RelNotes-1.6.0.2.txt[1.6.0.2],
 125   link:RelNotes-1.6.0.1.txt[1.6.0.1],
 126   link:RelNotes-1.6.0.txt[1.6.0].
 127
 128 * link:v1.5.6.6/git.html[documentation for release 1.5.6.6]
 129
 130 * release notes for
 131   link:RelNotes-1.5.6.6.txt[1.5.6.6],
 132   link:RelNotes-1.5.6.5.txt[1.5.6.5],
 133   link:RelNotes-1.5.6.4.txt[1.5.6.4],
 134   link:RelNotes-1.5.6.3.txt[1.5.6.3],
 135   link:RelNotes-1.5.6.2.txt[1.5.6.2],
 136   link:RelNotes-1.5.6.1.txt[1.5.6.1],
 137   link:RelNotes-1.5.6.txt[1.5.6].
 138
 139 * link:v1.5.5.6/git.html[documentation for release 1.5.5.6]
 140
 141 * release notes for
 142   link:RelNotes-1.5.5.6.txt[1.5.5.6],
 143   link:RelNotes-1.5.5.5.txt[1.5.5.5],
 144   link:RelNotes-1.5.5.4.txt[1.5.5.4],
 145   link:RelNotes-1.5.5.3.txt[1.5.5.3],
 146   link:RelNotes-1.5.5.2.txt[1.5.5.2],
 147   link:RelNotes-1.5.5.1.txt[1.5.5.1],
 148   link:RelNotes-1.5.5.txt[1.5.5].
 149
 150 * link:v1.5.4.7/git.html[documentation for release 1.5.4.7]
 151
 152 * release notes for
 153   link:RelNotes-1.5.4.7.txt[1.5.4.7],
 154   link:RelNotes-1.5.4.6.txt[1.5.4.6],
 155   link:RelNotes-1.5.4.5.txt[1.5.4.5],
 156   link:RelNotes-1.5.4.4.txt[1.5.4.4],
 157   link:RelNotes-1.5.4.3.txt[1.5.4.3],
 158   link:RelNotes-1.5.4.2.txt[1.5.4.2],
 159   link:RelNotes-1.5.4.1.txt[1.5.4.1],
 160   link:RelNotes-1.5.4.txt[1.5.4].
 161
 162 * link:v1.5.3.8/git.html[documentation for release 1.5.3.8]
 163
 164 * release notes for
 165   link:RelNotes-1.5.3.8.txt[1.5.3.8],
 166   link:RelNotes-1.5.3.7.txt[1.5.3.7],
 167   link:RelNotes-1.5.3.6.txt[1.5.3.6],
 168   link:RelNotes-1.5.3.5.txt[1.5.3.5],
 169   link:RelNotes-1.5.3.4.txt[1.5.3.4],
 170   link:RelNotes-1.5.3.3.txt[1.5.3.3],
 171   link:RelNotes-1.5.3.2.txt[1.5.3.2],
 172   link:RelNotes-1.5.3.1.txt[1.5.3.1],
 173   link:RelNotes-1.5.3.txt[1.5.3].
 174
 175 * link:v1.5.2.5/git.html[documentation for release 1.5.2.5]
 176
 177 * release notes for
 178   link:RelNotes-1.5.2.5.txt[1.5.2.5],
 179   link:RelNotes-1.5.2.4.txt[1.5.2.4],
 180   link:RelNotes-1.5.2.3.txt[1.5.2.3],
 181   link:RelNotes-1.5.2.2.txt[1.5.2.2],
 182   link:RelNotes-1.5.2.1.txt[1.5.2.1],
 183   link:RelNotes-1.5.2.txt[1.5.2].
 184
 185 * link:v1.5.1.6/git.html[documentation for release 1.5.1.6]
 186
 187 * release notes for
 188   link:RelNotes-1.5.1.6.txt[1.5.1.6],
 189   link:RelNotes-1.5.1.5.txt[1.5.1.5],
 190   link:RelNotes-1.5.1.4.txt[1.5.1.4],
 191   link:RelNotes-1.5.1.3.txt[1.5.1.3],
 192   link:RelNotes-1.5.1.2.txt[1.5.1.2],
 193   link:RelNotes-1.5.1.1.txt[1.5.1.1],
 194   link:RelNotes-1.5.1.txt[1.5.1].
 195
 196 * link:v1.5.0.7/git.html[documentation for release 1.5.0.7]
 197
 198 * release notes for
 199   link:RelNotes-1.5.0.7.txt[1.5.0.7],
 200   link:RelNotes-1.5.0.6.txt[1.5.0.6],
 201   link:RelNotes-1.5.0.5.txt[1.5.0.5],
 202   link:RelNotes-1.5.0.3.txt[1.5.0.3],
 203   link:RelNotes-1.5.0.2.txt[1.5.0.2],
 204   link:RelNotes-1.5.0.1.txt[1.5.0.1],
 205   link:RelNotes-1.5.0.txt[1.5.0].
 206
 207 * documentation for release link:v1.4.4.4/git.html[1.4.4.4],
 208   link:v1.3.3/git.html[1.3.3],
 209   link:v1.2.6/git.html[1.2.6],
 210   link:v1.0.13/git.html[1.0.13].
 211
 212 ============
 213
 214 endif::stalenotes[]
 215
 216 OPTIONS
 217 -------
 218 --version::
 219         Prints the git suite version that the 'git' program came from.
 220
 221 --help::
 222         Prints the synopsis and a list of the most commonly used
 223         commands. If the option '--all' or '-a' is given then all
 224         available commands are printed. If a git command is named this
 225         option will bring up the manual page for that command.
 226 +
 227 Other options are available to control how the manual page is
 228 displayed. See linkgit:git-help[1] for more information,
 229 because `git --help ...` is converted internally into `git
 230 help ...`.
 231
 232 -c <name>=<value>::
 233         Pass a configuration parameter to the command. The value
 234         given will override values from configuration files.
 235         The <name> is expected in the same format as listed by
 236         'git config' (subkeys separated by dots).
 237
 238 --exec-path::
 239         Path to wherever your core git programs are installed.
 240         This can also be controlled by setting the GIT_EXEC_PATH
 241         environment variable. If no path is given, 'git' will print
 242         the current setting and then exit.
 243
 244 --html-path::
 245         Print the path to wherever your git HTML documentation is installed
 246         and exit.
 247
 248 -p::
 249 --paginate::
 250         Pipe all output into 'less' (or if set, $PAGER) if standard
 251         output is a terminal.  This overrides the `pager.<cmd>`
 252         configuration options (see the "Configuration Mechanism" section
 253         below).
 254
 255 --no-pager::
 256         Do not pipe git output into a pager.
 257
 258 --git-dir=<path>::
 259         Set the path to the repository. This can also be controlled by
 260         setting the GIT_DIR environment variable. It can be an absolute
 261         path or relative path to current working directory.
 262
 263 --work-tree=<path>::
 264         Set the path to the working tree.  The value will not be
 265         used in combination with repositories found automatically in
 266         a .git directory (i.e. $GIT_DIR is not set).
 267         This can also be controlled by setting the GIT_WORK_TREE
 268         environment variable and the core.worktree configuration
 269         variable. It can be an absolute path or relative path to
 270         the directory specified by --git-dir or GIT_DIR.
 271         Note: If --git-dir or GIT_DIR are specified but none of
 272         --work-tree, GIT_WORK_TREE and core.worktree is specified,
 273         the current working directory is regarded as the top directory
 274         of your working tree.
 275
 276 --bare::
 277         Treat the repository as a bare repository.  If GIT_DIR
 278         environment is not set, it is set to the current working
 279         directory.
 280
 281 --no-replace-objects::
 282         Do not use replacement refs to replace git objects. See
 283         linkgit:git-replace[1] for more information.
 284
 285
 286 FURTHER DOCUMENTATION
 287 ---------------------
 288
 289 See the references above to get started using git.  The following is
 290 probably more detail than necessary for a first-time user.
 291
 292 The link:user-manual.html#git-concepts[git concepts chapter of the
 293 user-manual] and linkgit:gitcore-tutorial[7] both provide
 294 introductions to the underlying git architecture.
 295
 296 See linkgit:gitworkflows[7] for an overview of recommended workflows.
 297
 298 See also the link:howto-index.html[howto] documents for some useful
 299 examples.
 300
 301 The internals are documented in the
 302 link:technical/api-index.html[GIT API documentation].
 303
 304 GIT COMMANDS
 305 ------------
 306
 307 We divide git into high level ("porcelain") commands and low level
 308 ("plumbing") commands.
 309
 310 High-level commands (porcelain)
 311 -------------------------------
 312
 313 We separate the porcelain commands into the main commands and some
 314 ancillary user utilities.
 315
 316 Main porcelain commands
 317 ~~~~~~~~~~~~~~~~~~~~~~~
 318
 319 include::cmds-mainporcelain.txt[]
 320
 321 Ancillary Commands
 322 ~~~~~~~~~~~~~~~~~~
 323 Manipulators:
 324
 325 include::cmds-ancillarymanipulators.txt[]
 326
 327 Interrogators:
 328
 329 include::cmds-ancillaryinterrogators.txt[]
 330
 331
 332 Interacting with Others
 333 ~~~~~~~~~~~~~~~~~~~~~~~
 334
 335 These commands are to interact with foreign SCM and with other
 336 people via patch over e-mail.
 337
 338 include::cmds-foreignscminterface.txt[]
 339
 340
 341 Low-level commands (plumbing)
 342 -----------------------------
 343
 344 Although git includes its
 345 own porcelain layer, its low-level commands are sufficient to support
 346 development of alternative porcelains.  Developers of such porcelains
 347 might start by reading about linkgit:git-update-index[1] and
 348 linkgit:git-read-tree[1].
 349
 350 The interface (input, output, set of options and the semantics)
 351 to these low-level commands are meant to be a lot more stable
 352 than Porcelain level commands, because these commands are
 353 primarily for scripted use.  The interface to Porcelain commands
 354 on the other hand are subject to change in order to improve the
 355 end user experience.
 356
 357 The following description divides
 358 the low-level commands into commands that manipulate objects (in
 359 the repository, index, and working tree), commands that interrogate and
 360 compare objects, and commands that move objects and references between
 361 repositories.
 362
 363
 364 Manipulation commands
 365 ~~~~~~~~~~~~~~~~~~~~~
 366
 367 include::cmds-plumbingmanipulators.txt[]
 368
 369
 370 Interrogation commands
 371 ~~~~~~~~~~~~~~~~~~~~~~
 372
 373 include::cmds-plumbinginterrogators.txt[]
 374
 375 In general, the interrogate commands do not touch the files in
 376 the working tree.
 377
 378
 379 Synching repositories
 380 ~~~~~~~~~~~~~~~~~~~~~
 381
 382 include::cmds-synchingrepositories.txt[]
 383
 384 The following are helper commands used by the above; end users
 385 typically do not use them directly.
 386
 387 include::cmds-synchelpers.txt[]
 388
 389
 390 Internal helper commands
 391 ~~~~~~~~~~~~~~~~~~~~~~~~
 392
 393 These are internal helper commands used by other commands; end
 394 users typically do not use them directly.
 395
 396 include::cmds-purehelpers.txt[]
 397
 398
 399 Configuration Mechanism
 400 -----------------------
 401
 402 Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file
 403 is used to hold per-repository configuration options.  It is a
 404 simple text file modeled after `.ini` format familiar to some
 405 people.  Here is an example:
 406
 407 ------------
 408 #
 409 # A '#' or ';' character indicates a comment.
 410 #
 411
 412 ; core variables
 413 [core]
 414         ; Don't trust file modes
 415         filemode = false
 416
 417 ; user identity
 418 [user]
 419         name = "Junio C Hamano"
 420         email = "junkio@twinsun.com"
 421
 422 ------------
 423
 424 Various commands read from the configuration file and adjust
 425 their operation accordingly.  See linkgit:git-config[1] for a
 426 list.
 427
 428
 429 Identifier Terminology
 430 ----------------------
 431 <object>::
 432         Indicates the object name for any type of object.
 433
 434 <blob>::
 435         Indicates a blob object name.
 436
 437 <tree>::
 438         Indicates a tree object name.
 439
 440 <commit>::
 441         Indicates a commit object name.
 442
 443 <tree-ish>::
 444         Indicates a tree, commit or tag object name.  A
 445         command that takes a <tree-ish> argument ultimately wants to
 446         operate on a <tree> object but automatically dereferences
 447         <commit> and <tag> objects that point at a <tree>.
 448
 449 <commit-ish>::
 450         Indicates a commit or tag object name.  A
 451         command that takes a <commit-ish> argument ultimately wants to
 452         operate on a <commit> object but automatically dereferences
 453         <tag> objects that point at a <commit>.
 454
 455 <type>::
 456         Indicates that an object type is required.
 457         Currently one of: `blob`, `tree`, `commit`, or `tag`.
 458
 459 <file>::
 460         Indicates a filename - almost always relative to the
 461         root of the tree structure `GIT_INDEX_FILE` describes.
 462
 463 Symbolic Identifiers
 464 --------------------
 465 Any git command accepting any <object> can also use the following
 466 symbolic notation:
 467
 468 HEAD::
 469         indicates the head of the current branch (i.e. the
 470         contents of `$GIT_DIR/HEAD`).
 471
 472 <tag>::
 473         a valid tag 'name'
 474         (i.e. the contents of `$GIT_DIR/refs/tags/<tag>`).
 475
 476 <head>::
 477         a valid head 'name'
 478         (i.e. the contents of `$GIT_DIR/refs/heads/<head>`).
 479
 480 For a more complete list of ways to spell object names, see
 481 "SPECIFYING REVISIONS" section in linkgit:git-rev-parse[1].
 482
 483
 484 File/Directory Structure
 485 ------------------------
 486
 487 Please see the linkgit:gitrepository-layout[5] document.
 488
 489 Read linkgit:githooks[5] for more details about each hook.
 490
 491 Higher level SCMs may provide and manage additional information in the
 492 `$GIT_DIR`.
 493
 494
 495 Terminology
 496 -----------
 497 Please see linkgit:gitglossary[7].
 498
 499
 500 Environment Variables
 501 ---------------------
 502 Various git commands use the following environment variables:
 503
 504 The git Repository
 505 ~~~~~~~~~~~~~~~~~~
 506 These environment variables apply to 'all' core git commands. Nb: it
 507 is worth noting that they may be used/overridden by SCMS sitting above
 508 git so take care if using Cogito etc.
 509
 510 'GIT_INDEX_FILE'::
 511         This environment allows the specification of an alternate
 512         index file. If not specified, the default of `$GIT_DIR/index`
 513         is used.
 514
 515 'GIT_OBJECT_DIRECTORY'::
 516         If the object storage directory is specified via this
 517         environment variable then the sha1 directories are created
 518         underneath - otherwise the default `$GIT_DIR/objects`
 519         directory is used.
 520
 521 'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
 522         Due to the immutable nature of git objects, old objects can be
 523         archived into shared, read-only directories. This variable
 524         specifies a ":" separated (on Windows ";" separated) list
 525         of git object directories which can be used to search for git
 526         objects. New objects will not be written to these directories.
 527
 528 'GIT_DIR'::
 529         If the 'GIT_DIR' environment variable is set then it
 530         specifies a path to use instead of the default `.git`
 531         for the base of the repository.
 532
 533 'GIT_WORK_TREE'::
 534         Set the path to the working tree.  The value will not be
 535         used in combination with repositories found automatically in
 536         a .git directory (i.e. $GIT_DIR is not set).
 537         This can also be controlled by the '--work-tree' command line
 538         option and the core.worktree configuration variable.
 539
 540 'GIT_CEILING_DIRECTORIES'::
 541         This should be a colon-separated list of absolute paths.
 542         If set, it is a list of directories that git should not chdir
 543         up into while looking for a repository directory.
 544         It will not exclude the current working directory or
 545         a GIT_DIR set on the command line or in the environment.
 546         (Useful for excluding slow-loading network directories.)
 547
 548 'GIT_DISCOVERY_ACROSS_FILESYSTEM'::
 549         When run in a directory that does not have ".git" repository
 550         directory, git tries to find such a directory in the parent
 551         directories to find the top of the working tree, but by default it
 552         does not cross filesystem boundaries.  This environment variable
 553         can be set to true to tell git not to stop at filesystem
 554         boundaries.  Like 'GIT_CEILING_DIRECTORIES', this will not affect
 555         an explicit repository directory set via 'GIT_DIR' or on the
 556         command line.
 557
 558 git Commits
 559 ~~~~~~~~~~~
 560 'GIT_AUTHOR_NAME'::
 561 'GIT_AUTHOR_EMAIL'::
 562 'GIT_AUTHOR_DATE'::
 563 'GIT_COMMITTER_NAME'::
 564 'GIT_COMMITTER_EMAIL'::
 565 'GIT_COMMITTER_DATE'::
 566 'EMAIL'::
 567         see linkgit:git-commit-tree[1]
 568
 569 git Diffs
 570 ~~~~~~~~~
 571 'GIT_DIFF_OPTS'::
 572         Only valid setting is "--unified=??" or "-u??" to set the
 573         number of context lines shown when a unified diff is created.
 574         This takes precedence over any "-U" or "--unified" option
 575         value passed on the git diff command line.
 576
 577 'GIT_EXTERNAL_DIFF'::
 578         When the environment variable 'GIT_EXTERNAL_DIFF' is set, the
 579         program named by it is called, instead of the diff invocation
 580         described above.  For a path that is added, removed, or modified,
 581         'GIT_EXTERNAL_DIFF' is called with 7 parameters:
 582
 583         path old-file old-hex old-mode new-file new-hex new-mode
 584 +
 585 where:
 586
 587         <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the
 588                          contents of <old|new>,
 589         <old|new>-hex:: are the 40-hexdigit SHA1 hashes,
 590         <old|new>-mode:: are the octal representation of the file modes.
 591
 592 +
 593 The file parameters can point at the user's working file
 594 (e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
 595 when a new file is added), or a temporary file (e.g. `old-file` in the
 596 index).  'GIT_EXTERNAL_DIFF' should not worry about unlinking the
 597 temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits.
 598 +
 599 For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1
 600 parameter, <path>.
 601
 602 other
 603 ~~~~~
 604 'GIT_MERGE_VERBOSITY'::
 605         A number controlling the amount of output shown by
 606         the recursive merge strategy.  Overrides merge.verbosity.
 607         See linkgit:git-merge[1]
 608
 609 'GIT_PAGER'::
 610         This environment variable overrides `$PAGER`. If it is set
 611         to an empty string or to the value "cat", git will not launch
 612         a pager.  See also the `core.pager` option in
 613         linkgit:git-config[1].
 614
 615 'GIT_SSH'::
 616         If this environment variable is set then 'git fetch'
 617         and 'git push' will use this command instead
 618         of 'ssh' when they need to connect to a remote system.
 619         The '$GIT_SSH' command will be given exactly two arguments:
 620         the 'username@host' (or just 'host') from the URL and the
 621         shell command to execute on that remote system.
 622 +
 623 To pass options to the program that you want to list in GIT_SSH
 624 you will need to wrap the program and options into a shell script,
 625 then set GIT_SSH to refer to the shell script.
 626 +
 627 Usually it is easier to configure any desired options through your
 628 personal `.ssh/config` file.  Please consult your ssh documentation
 629 for further details.
 630
 631 'GIT_FLUSH'::
 632         If this environment variable is set to "1", then commands such
 633         as 'git blame' (in incremental mode), 'git rev-list', 'git log',
 634         and 'git whatchanged' will force a flush of the output stream
 635         after each commit-oriented record have been flushed.   If this
 636         variable is set to "0", the output of these commands will be done
 637         using completely buffered I/O.   If this environment variable is
 638         not set, git will choose buffered or record-oriented flushing
 639         based on whether stdout appears to be redirected to a file or not.
 640
 641 'GIT_TRACE'::
 642         If this variable is set to "1", "2" or "true" (comparison
 643         is case insensitive), git will print `trace:` messages on
 644         stderr telling about alias expansion, built-in command
 645         execution and external command execution.
 646         If this variable is set to an integer value greater than 1
 647         and lower than 10 (strictly) then git will interpret this
 648         value as an open file descriptor and will try to write the
 649         trace messages into this file descriptor.
 650         Alternatively, if this variable is set to an absolute path
 651         (starting with a '/' character), git will interpret this
 652         as a file path and will try to write the trace messages
 653         into it.
 654
 655 Discussion[[Discussion]]
 656 ------------------------
 657
 658 More detail on the following is available from the
 659 link:user-manual.html#git-concepts[git concepts chapter of the
 660 user-manual] and linkgit:gitcore-tutorial[7].
 661
 662 A git project normally consists of a working directory with a ".git"
 663 subdirectory at the top level.  The .git directory contains, among other
 664 things, a compressed object database representing the complete history
 665 of the project, an "index" file which links that history to the current
 666 contents of the working tree, and named pointers into that history such
 667 as tags and branch heads.
 668
 669 The object database contains objects of three main types: blobs, which
 670 hold file data; trees, which point to blobs and other trees to build up
 671 directory hierarchies; and commits, which each reference a single tree
 672 and some number of parent commits.
 673
 674 The commit, equivalent to what other systems call a "changeset" or
 675 "version", represents a step in the project's history, and each parent
 676 represents an immediately preceding step.  Commits with more than one
 677 parent represent merges of independent lines of development.
 678
 679 All objects are named by the SHA1 hash of their contents, normally
 680 written as a string of 40 hex digits.  Such names are globally unique.
 681 The entire history leading up to a commit can be vouched for by signing
 682 just that commit.  A fourth object type, the tag, is provided for this
 683 purpose.
 684
 685 When first created, objects are stored in individual files, but for
 686 efficiency may later be compressed together into "pack files".
 687
 688 Named pointers called refs mark interesting points in history.  A ref
 689 may contain the SHA1 name of an object or the name of another ref.  Refs
 690 with names beginning `ref/head/` contain the SHA1 name of the most
 691 recent commit (or "head") of a branch under development.  SHA1 names of
 692 tags of interest are stored under `ref/tags/`.  A special ref named
 693 `HEAD` contains the name of the currently checked-out branch.
 694
 695 The index file is initialized with a list of all paths and, for each
 696 path, a blob object and a set of attributes.  The blob object represents
 697 the contents of the file as of the head of the current branch.  The
 698 attributes (last modified time, size, etc.) are taken from the
 699 corresponding file in the working tree.  Subsequent changes to the
 700 working tree can be found by comparing these attributes.  The index may
 701 be updated with new content, and new commits may be created from the
 702 content stored in the index.
 703
 704 The index is also capable of storing multiple entries (called "stages")
 705 for a given pathname.  These stages are used to hold the various
 706 unmerged version of a file when a merge is in progress.
 707
 708 Authors
 709 -------
 710 * git's founding father is Linus Torvalds <torvalds@osdl.org>.
 711 * The current git nurse is Junio C Hamano <gitster@pobox.com>.
 712 * The git potty was written by Andreas Ericsson <ae@op5.se>.
 713 * General upbringing is handled by the git-list <git@vger.kernel.org>.
 714
 715 Documentation
 716 --------------
 717 The documentation for git suite was started by David Greaves
 718 <david@dgreaves.com>, and later enhanced greatly by the
 719 contributors on the git-list <git@vger.kernel.org>.
 720
 721 SEE ALSO
 722 --------
 723 linkgit:gittutorial[7], linkgit:gittutorial-2[7],
 724 link:everyday.html[Everyday Git], linkgit:gitcvs-migration[7],
 725 linkgit:gitglossary[7], linkgit:gitcore-tutorial[7],
 726 linkgit:gitcli[7], link:user-manual.html[The Git User's Manual],
 727 linkgit:gitworkflows[7]
 728
 729 GIT
 730 ---
 731 Part of the linkgit:git[1] suite