Documentation / git.txton commit Merge branch 'maint-1.7.7' into maint-1.7.8 (e521850)
   1git(1)
   2======
   3
   4NAME
   5----
   6git - the stupid content tracker
   7
   8
   9SYNOPSIS
  10--------
  11[verse]
  12'git' [--version] [--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]
  13    [-p|--paginate|--no-pager] [--no-replace-objects] [--bare]
  14    [--git-dir=<path>] [--work-tree=<path>] [--namespace=<name>]
  15    [-c <name>=<value>]
  16    [--help] <command> [<args>]
  17
  18DESCRIPTION
  19-----------
  20Git is a fast, scalable, distributed revision control system with an
  21unusually rich command set that provides both high-level operations
  22and full access to internals.
  23
  24See linkgit:gittutorial[7] to get started, then see
  25link:everyday.html[Everyday Git] for a useful minimum set of commands, and
  26"man git-commandname" for documentation of each command.  CVS users may
  27also want to read linkgit:gitcvs-migration[7].  See
  28the link:user-manual.html[Git User's Manual] for a more in-depth
  29introduction.
  30
  31The '<command>' is either a name of a Git command (see below) or an alias
  32as defined in the configuration file (see linkgit:git-config[1]).
  33
  34Formatted and hyperlinked version of the latest git
  35documentation can be viewed at
  36`http://www.kernel.org/pub/software/scm/git/docs/`.
  37
  38ifdef::stalenotes[]
  39[NOTE]
  40============
  41
  42You are reading the documentation for the latest (possibly
  43unreleased) version of git, that is available from 'master'
  44branch of the `git.git` repository.
  45Documentation for older releases are available here:
  46
  47* link:v1.7.8.4/git.html[documentation for release 1.7.8.4]
  48
  49* release notes for
  50  link:RelNotes/1.7.8.4.txt[1.7.8.4],
  51  link:RelNotes/1.7.8.3.txt[1.7.8.3],
  52  link:RelNotes/1.7.8.2.txt[1.7.8.2],
  53  link:RelNotes/1.7.8.1.txt[1.7.8.1],
  54  link:RelNotes/1.7.8.txt[1.7.8].
  55
  56* link:v1.7.7.6/git.html[documentation for release 1.7.7.6]
  57
  58* release notes for
  59  link:RelNotes/1.7.7.6.txt[1.7.7.6],
  60  link:RelNotes/1.7.7.5.txt[1.7.7.5],
  61  link:RelNotes/1.7.7.4.txt[1.7.7.4],
  62  link:RelNotes/1.7.7.3.txt[1.7.7.3],
  63  link:RelNotes/1.7.7.2.txt[1.7.7.2],
  64  link:RelNotes/1.7.7.1.txt[1.7.7.1],
  65  link:RelNotes/1.7.7.txt[1.7.7].
  66
  67* link:v1.7.6.6/git.html[documentation for release 1.7.6.6]
  68
  69* release notes for
  70  link:RelNotes/1.7.6.6.txt[1.7.6.6],
  71  link:RelNotes/1.7.6.5.txt[1.7.6.5],
  72  link:RelNotes/1.7.6.4.txt[1.7.6.4],
  73  link:RelNotes/1.7.6.3.txt[1.7.6.3],
  74  link:RelNotes/1.7.6.2.txt[1.7.6.2],
  75  link:RelNotes/1.7.6.1.txt[1.7.6.1],
  76  link:RelNotes/1.7.6.txt[1.7.6].
  77
  78* link:v1.7.5.4/git.html[documentation for release 1.7.5.4]
  79
  80* release notes for
  81  link:RelNotes/1.7.5.4.txt[1.7.5.4],
  82  link:RelNotes/1.7.5.3.txt[1.7.5.3],
  83  link:RelNotes/1.7.5.2.txt[1.7.5.2],
  84  link:RelNotes/1.7.5.1.txt[1.7.5.1],
  85  link:RelNotes/1.7.5.txt[1.7.5].
  86
  87* link:v1.7.4.5/git.html[documentation for release 1.7.4.5]
  88
  89* release notes for
  90  link:RelNotes/1.7.4.5.txt[1.7.4.5],
  91  link:RelNotes/1.7.4.4.txt[1.7.4.4],
  92  link:RelNotes/1.7.4.3.txt[1.7.4.3],
  93  link:RelNotes/1.7.4.2.txt[1.7.4.2],
  94  link:RelNotes/1.7.4.1.txt[1.7.4.1],
  95  link:RelNotes/1.7.4.txt[1.7.4].
  96
  97* link:v1.7.3.5/git.html[documentation for release 1.7.3.5]
  98
  99* release notes for
 100  link:RelNotes/1.7.3.5.txt[1.7.3.5],
 101  link:RelNotes/1.7.3.4.txt[1.7.3.4],
 102  link:RelNotes/1.7.3.3.txt[1.7.3.3],
 103  link:RelNotes/1.7.3.2.txt[1.7.3.2],
 104  link:RelNotes/1.7.3.1.txt[1.7.3.1],
 105  link:RelNotes/1.7.3.txt[1.7.3].
 106
 107* link:v1.7.2.5/git.html[documentation for release 1.7.2.5]
 108
 109* release notes for
 110  link:RelNotes/1.7.2.5.txt[1.7.2.5],
 111  link:RelNotes/1.7.2.4.txt[1.7.2.4],
 112  link:RelNotes/1.7.2.3.txt[1.7.2.3],
 113  link:RelNotes/1.7.2.2.txt[1.7.2.2],
 114  link:RelNotes/1.7.2.1.txt[1.7.2.1],
 115  link:RelNotes/1.7.2.txt[1.7.2].
 116
 117* link:v1.7.1.4/git.html[documentation for release 1.7.1.4]
 118
 119* release notes for
 120  link:RelNotes/1.7.1.4.txt[1.7.1.4],
 121  link:RelNotes/1.7.1.3.txt[1.7.1.3],
 122  link:RelNotes/1.7.1.2.txt[1.7.1.2],
 123  link:RelNotes/1.7.1.1.txt[1.7.1.1],
 124  link:RelNotes/1.7.1.txt[1.7.1].
 125
 126* link:v1.7.0.9/git.html[documentation for release 1.7.0.9]
 127
 128* release notes for
 129  link:RelNotes/1.7.0.9.txt[1.7.0.9],
 130  link:RelNotes/1.7.0.8.txt[1.7.0.8],
 131  link:RelNotes/1.7.0.7.txt[1.7.0.7],
 132  link:RelNotes/1.7.0.6.txt[1.7.0.6],
 133  link:RelNotes/1.7.0.5.txt[1.7.0.5],
 134  link:RelNotes/1.7.0.4.txt[1.7.0.4],
 135  link:RelNotes/1.7.0.3.txt[1.7.0.3],
 136  link:RelNotes/1.7.0.2.txt[1.7.0.2],
 137  link:RelNotes/1.7.0.1.txt[1.7.0.1],
 138  link:RelNotes/1.7.0.txt[1.7.0].
 139
 140* link:v1.6.6.3/git.html[documentation for release 1.6.6.3]
 141
 142* release notes for
 143  link:RelNotes/1.6.6.3.txt[1.6.6.3],
 144  link:RelNotes/1.6.6.2.txt[1.6.6.2],
 145  link:RelNotes/1.6.6.1.txt[1.6.6.1],
 146  link:RelNotes/1.6.6.txt[1.6.6].
 147
 148* link:v1.6.5.9/git.html[documentation for release 1.6.5.9]
 149
 150* release notes for
 151  link:RelNotes/1.6.5.9.txt[1.6.5.9],
 152  link:RelNotes/1.6.5.8.txt[1.6.5.8],
 153  link:RelNotes/1.6.5.7.txt[1.6.5.7],
 154  link:RelNotes/1.6.5.6.txt[1.6.5.6],
 155  link:RelNotes/1.6.5.5.txt[1.6.5.5],
 156  link:RelNotes/1.6.5.4.txt[1.6.5.4],
 157  link:RelNotes/1.6.5.3.txt[1.6.5.3],
 158  link:RelNotes/1.6.5.2.txt[1.6.5.2],
 159  link:RelNotes/1.6.5.1.txt[1.6.5.1],
 160  link:RelNotes/1.6.5.txt[1.6.5].
 161
 162* link:v1.6.4.5/git.html[documentation for release 1.6.4.5]
 163
 164* release notes for
 165  link:RelNotes/1.6.4.5.txt[1.6.4.5],
 166  link:RelNotes/1.6.4.4.txt[1.6.4.4],
 167  link:RelNotes/1.6.4.3.txt[1.6.4.3],
 168  link:RelNotes/1.6.4.2.txt[1.6.4.2],
 169  link:RelNotes/1.6.4.1.txt[1.6.4.1],
 170  link:RelNotes/1.6.4.txt[1.6.4].
 171
 172* link:v1.6.3.4/git.html[documentation for release 1.6.3.4]
 173
 174* release notes for
 175  link:RelNotes/1.6.3.4.txt[1.6.3.4],
 176  link:RelNotes/1.6.3.3.txt[1.6.3.3],
 177  link:RelNotes/1.6.3.2.txt[1.6.3.2],
 178  link:RelNotes/1.6.3.1.txt[1.6.3.1],
 179  link:RelNotes/1.6.3.txt[1.6.3].
 180
 181* release notes for
 182  link:RelNotes/1.6.2.5.txt[1.6.2.5],
 183  link:RelNotes/1.6.2.4.txt[1.6.2.4],
 184  link:RelNotes/1.6.2.3.txt[1.6.2.3],
 185  link:RelNotes/1.6.2.2.txt[1.6.2.2],
 186  link:RelNotes/1.6.2.1.txt[1.6.2.1],
 187  link:RelNotes/1.6.2.txt[1.6.2].
 188
 189* link:v1.6.1.3/git.html[documentation for release 1.6.1.3]
 190
 191* release notes for
 192  link:RelNotes/1.6.1.3.txt[1.6.1.3],
 193  link:RelNotes/1.6.1.2.txt[1.6.1.2],
 194  link:RelNotes/1.6.1.1.txt[1.6.1.1],
 195  link:RelNotes/1.6.1.txt[1.6.1].
 196
 197* link:v1.6.0.6/git.html[documentation for release 1.6.0.6]
 198
 199* release notes for
 200  link:RelNotes/1.6.0.6.txt[1.6.0.6],
 201  link:RelNotes/1.6.0.5.txt[1.6.0.5],
 202  link:RelNotes/1.6.0.4.txt[1.6.0.4],
 203  link:RelNotes/1.6.0.3.txt[1.6.0.3],
 204  link:RelNotes/1.6.0.2.txt[1.6.0.2],
 205  link:RelNotes/1.6.0.1.txt[1.6.0.1],
 206  link:RelNotes/1.6.0.txt[1.6.0].
 207
 208* link:v1.5.6.6/git.html[documentation for release 1.5.6.6]
 209
 210* release notes for
 211  link:RelNotes/1.5.6.6.txt[1.5.6.6],
 212  link:RelNotes/1.5.6.5.txt[1.5.6.5],
 213  link:RelNotes/1.5.6.4.txt[1.5.6.4],
 214  link:RelNotes/1.5.6.3.txt[1.5.6.3],
 215  link:RelNotes/1.5.6.2.txt[1.5.6.2],
 216  link:RelNotes/1.5.6.1.txt[1.5.6.1],
 217  link:RelNotes/1.5.6.txt[1.5.6].
 218
 219* link:v1.5.5.6/git.html[documentation for release 1.5.5.6]
 220
 221* release notes for
 222  link:RelNotes/1.5.5.6.txt[1.5.5.6],
 223  link:RelNotes/1.5.5.5.txt[1.5.5.5],
 224  link:RelNotes/1.5.5.4.txt[1.5.5.4],
 225  link:RelNotes/1.5.5.3.txt[1.5.5.3],
 226  link:RelNotes/1.5.5.2.txt[1.5.5.2],
 227  link:RelNotes/1.5.5.1.txt[1.5.5.1],
 228  link:RelNotes/1.5.5.txt[1.5.5].
 229
 230* link:v1.5.4.7/git.html[documentation for release 1.5.4.7]
 231
 232* release notes for
 233  link:RelNotes/1.5.4.7.txt[1.5.4.7],
 234  link:RelNotes/1.5.4.6.txt[1.5.4.6],
 235  link:RelNotes/1.5.4.5.txt[1.5.4.5],
 236  link:RelNotes/1.5.4.4.txt[1.5.4.4],
 237  link:RelNotes/1.5.4.3.txt[1.5.4.3],
 238  link:RelNotes/1.5.4.2.txt[1.5.4.2],
 239  link:RelNotes/1.5.4.1.txt[1.5.4.1],
 240  link:RelNotes/1.5.4.txt[1.5.4].
 241
 242* link:v1.5.3.8/git.html[documentation for release 1.5.3.8]
 243
 244* release notes for
 245  link:RelNotes/1.5.3.8.txt[1.5.3.8],
 246  link:RelNotes/1.5.3.7.txt[1.5.3.7],
 247  link:RelNotes/1.5.3.6.txt[1.5.3.6],
 248  link:RelNotes/1.5.3.5.txt[1.5.3.5],
 249  link:RelNotes/1.5.3.4.txt[1.5.3.4],
 250  link:RelNotes/1.5.3.3.txt[1.5.3.3],
 251  link:RelNotes/1.5.3.2.txt[1.5.3.2],
 252  link:RelNotes/1.5.3.1.txt[1.5.3.1],
 253  link:RelNotes/1.5.3.txt[1.5.3].
 254
 255* link:v1.5.2.5/git.html[documentation for release 1.5.2.5]
 256
 257* release notes for
 258  link:RelNotes/1.5.2.5.txt[1.5.2.5],
 259  link:RelNotes/1.5.2.4.txt[1.5.2.4],
 260  link:RelNotes/1.5.2.3.txt[1.5.2.3],
 261  link:RelNotes/1.5.2.2.txt[1.5.2.2],
 262  link:RelNotes/1.5.2.1.txt[1.5.2.1],
 263  link:RelNotes/1.5.2.txt[1.5.2].
 264
 265* link:v1.5.1.6/git.html[documentation for release 1.5.1.6]
 266
 267* release notes for
 268  link:RelNotes/1.5.1.6.txt[1.5.1.6],
 269  link:RelNotes/1.5.1.5.txt[1.5.1.5],
 270  link:RelNotes/1.5.1.4.txt[1.5.1.4],
 271  link:RelNotes/1.5.1.3.txt[1.5.1.3],
 272  link:RelNotes/1.5.1.2.txt[1.5.1.2],
 273  link:RelNotes/1.5.1.1.txt[1.5.1.1],
 274  link:RelNotes/1.5.1.txt[1.5.1].
 275
 276* link:v1.5.0.7/git.html[documentation for release 1.5.0.7]
 277
 278* release notes for
 279  link:RelNotes/1.5.0.7.txt[1.5.0.7],
 280  link:RelNotes/1.5.0.6.txt[1.5.0.6],
 281  link:RelNotes/1.5.0.5.txt[1.5.0.5],
 282  link:RelNotes/1.5.0.3.txt[1.5.0.3],
 283  link:RelNotes/1.5.0.2.txt[1.5.0.2],
 284  link:RelNotes/1.5.0.1.txt[1.5.0.1],
 285  link:RelNotes/1.5.0.txt[1.5.0].
 286
 287* documentation for release link:v1.4.4.4/git.html[1.4.4.4],
 288  link:v1.3.3/git.html[1.3.3],
 289  link:v1.2.6/git.html[1.2.6],
 290  link:v1.0.13/git.html[1.0.13].
 291
 292============
 293
 294endif::stalenotes[]
 295
 296OPTIONS
 297-------
 298--version::
 299        Prints the git suite version that the 'git' program came from.
 300
 301--help::
 302        Prints the synopsis and a list of the most commonly used
 303        commands. If the option '--all' or '-a' is given then all
 304        available commands are printed. If a git command is named this
 305        option will bring up the manual page for that command.
 306+
 307Other options are available to control how the manual page is
 308displayed. See linkgit:git-help[1] for more information,
 309because `git --help ...` is converted internally into `git
 310help ...`.
 311
 312-c <name>=<value>::
 313        Pass a configuration parameter to the command. The value
 314        given will override values from configuration files.
 315        The <name> is expected in the same format as listed by
 316        'git config' (subkeys separated by dots).
 317
 318--exec-path[=<path>]::
 319        Path to wherever your core git programs are installed.
 320        This can also be controlled by setting the GIT_EXEC_PATH
 321        environment variable. If no path is given, 'git' will print
 322        the current setting and then exit.
 323
 324--html-path::
 325        Print the path, without trailing slash, where git's HTML
 326        documentation is installed and exit.
 327
 328--man-path::
 329        Print the manpath (see `man(1)`) for the man pages for
 330        this version of git and exit.
 331
 332--info-path::
 333        Print the path where the Info files documenting this
 334        version of git are installed and exit.
 335
 336-p::
 337--paginate::
 338        Pipe all output into 'less' (or if set, $PAGER) if standard
 339        output is a terminal.  This overrides the `pager.<cmd>`
 340        configuration options (see the "Configuration Mechanism" section
 341        below).
 342
 343--no-pager::
 344        Do not pipe git output into a pager.
 345
 346--git-dir=<path>::
 347        Set the path to the repository. This can also be controlled by
 348        setting the GIT_DIR environment variable. It can be an absolute
 349        path or relative path to current working directory.
 350
 351--work-tree=<path>::
 352        Set the path to the working tree. It can be an absolute path
 353        or a path relative to the current working directory.
 354        This can also be controlled by setting the GIT_WORK_TREE
 355        environment variable and the core.worktree configuration
 356        variable (see core.worktree in linkgit:git-config[1] for a
 357        more detailed discussion).
 358
 359--namespace=<path>::
 360        Set the git namespace.  See linkgit:gitnamespaces[7] for more
 361        details.  Equivalent to setting the `GIT_NAMESPACE` environment
 362        variable.
 363
 364--bare::
 365        Treat the repository as a bare repository.  If GIT_DIR
 366        environment is not set, it is set to the current working
 367        directory.
 368
 369--no-replace-objects::
 370        Do not use replacement refs to replace git objects. See
 371        linkgit:git-replace[1] for more information.
 372
 373
 374FURTHER DOCUMENTATION
 375---------------------
 376
 377See the references above to get started using git.  The following is
 378probably more detail than necessary for a first-time user.
 379
 380The link:user-manual.html#git-concepts[git concepts chapter of the
 381user-manual] and linkgit:gitcore-tutorial[7] both provide
 382introductions to the underlying git architecture.
 383
 384See linkgit:gitworkflows[7] for an overview of recommended workflows.
 385
 386See also the link:howto-index.html[howto] documents for some useful
 387examples.
 388
 389The internals are documented in the
 390link:technical/api-index.html[GIT API documentation].
 391
 392GIT COMMANDS
 393------------
 394
 395We divide git into high level ("porcelain") commands and low level
 396("plumbing") commands.
 397
 398High-level commands (porcelain)
 399-------------------------------
 400
 401We separate the porcelain commands into the main commands and some
 402ancillary user utilities.
 403
 404Main porcelain commands
 405~~~~~~~~~~~~~~~~~~~~~~~
 406
 407include::cmds-mainporcelain.txt[]
 408
 409Ancillary Commands
 410~~~~~~~~~~~~~~~~~~
 411Manipulators:
 412
 413include::cmds-ancillarymanipulators.txt[]
 414
 415Interrogators:
 416
 417include::cmds-ancillaryinterrogators.txt[]
 418
 419
 420Interacting with Others
 421~~~~~~~~~~~~~~~~~~~~~~~
 422
 423These commands are to interact with foreign SCM and with other
 424people via patch over e-mail.
 425
 426include::cmds-foreignscminterface.txt[]
 427
 428
 429Low-level commands (plumbing)
 430-----------------------------
 431
 432Although git includes its
 433own porcelain layer, its low-level commands are sufficient to support
 434development of alternative porcelains.  Developers of such porcelains
 435might start by reading about linkgit:git-update-index[1] and
 436linkgit:git-read-tree[1].
 437
 438The interface (input, output, set of options and the semantics)
 439to these low-level commands are meant to be a lot more stable
 440than Porcelain level commands, because these commands are
 441primarily for scripted use.  The interface to Porcelain commands
 442on the other hand are subject to change in order to improve the
 443end user experience.
 444
 445The following description divides
 446the low-level commands into commands that manipulate objects (in
 447the repository, index, and working tree), commands that interrogate and
 448compare objects, and commands that move objects and references between
 449repositories.
 450
 451
 452Manipulation commands
 453~~~~~~~~~~~~~~~~~~~~~
 454
 455include::cmds-plumbingmanipulators.txt[]
 456
 457
 458Interrogation commands
 459~~~~~~~~~~~~~~~~~~~~~~
 460
 461include::cmds-plumbinginterrogators.txt[]
 462
 463In general, the interrogate commands do not touch the files in
 464the working tree.
 465
 466
 467Synching repositories
 468~~~~~~~~~~~~~~~~~~~~~
 469
 470include::cmds-synchingrepositories.txt[]
 471
 472The following are helper commands used by the above; end users
 473typically do not use them directly.
 474
 475include::cmds-synchelpers.txt[]
 476
 477
 478Internal helper commands
 479~~~~~~~~~~~~~~~~~~~~~~~~
 480
 481These are internal helper commands used by other commands; end
 482users typically do not use them directly.
 483
 484include::cmds-purehelpers.txt[]
 485
 486
 487Configuration Mechanism
 488-----------------------
 489
 490Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file
 491is used to hold per-repository configuration options.  It is a
 492simple text file modeled after `.ini` format familiar to some
 493people.  Here is an example:
 494
 495------------
 496#
 497# A '#' or ';' character indicates a comment.
 498#
 499
 500; core variables
 501[core]
 502        ; Don't trust file modes
 503        filemode = false
 504
 505; user identity
 506[user]
 507        name = "Junio C Hamano"
 508        email = "junkio@twinsun.com"
 509
 510------------
 511
 512Various commands read from the configuration file and adjust
 513their operation accordingly.  See linkgit:git-config[1] for a
 514list.
 515
 516
 517Identifier Terminology
 518----------------------
 519<object>::
 520        Indicates the object name for any type of object.
 521
 522<blob>::
 523        Indicates a blob object name.
 524
 525<tree>::
 526        Indicates a tree object name.
 527
 528<commit>::
 529        Indicates a commit object name.
 530
 531<tree-ish>::
 532        Indicates a tree, commit or tag object name.  A
 533        command that takes a <tree-ish> argument ultimately wants to
 534        operate on a <tree> object but automatically dereferences
 535        <commit> and <tag> objects that point at a <tree>.
 536
 537<commit-ish>::
 538        Indicates a commit or tag object name.  A
 539        command that takes a <commit-ish> argument ultimately wants to
 540        operate on a <commit> object but automatically dereferences
 541        <tag> objects that point at a <commit>.
 542
 543<type>::
 544        Indicates that an object type is required.
 545        Currently one of: `blob`, `tree`, `commit`, or `tag`.
 546
 547<file>::
 548        Indicates a filename - almost always relative to the
 549        root of the tree structure `GIT_INDEX_FILE` describes.
 550
 551Symbolic Identifiers
 552--------------------
 553Any git command accepting any <object> can also use the following
 554symbolic notation:
 555
 556HEAD::
 557        indicates the head of the current branch.
 558
 559<tag>::
 560        a valid tag 'name'
 561        (i.e. a `refs/tags/<tag>` reference).
 562
 563<head>::
 564        a valid head 'name'
 565        (i.e. a `refs/heads/<head>` reference).
 566
 567For a more complete list of ways to spell object names, see
 568"SPECIFYING REVISIONS" section in linkgit:gitrevisions[7].
 569
 570
 571File/Directory Structure
 572------------------------
 573
 574Please see the linkgit:gitrepository-layout[5] document.
 575
 576Read linkgit:githooks[5] for more details about each hook.
 577
 578Higher level SCMs may provide and manage additional information in the
 579`$GIT_DIR`.
 580
 581
 582Terminology
 583-----------
 584Please see linkgit:gitglossary[7].
 585
 586
 587Environment Variables
 588---------------------
 589Various git commands use the following environment variables:
 590
 591The git Repository
 592~~~~~~~~~~~~~~~~~~
 593These environment variables apply to 'all' core git commands. Nb: it
 594is worth noting that they may be used/overridden by SCMS sitting above
 595git so take care if using Cogito etc.
 596
 597'GIT_INDEX_FILE'::
 598        This environment allows the specification of an alternate
 599        index file. If not specified, the default of `$GIT_DIR/index`
 600        is used.
 601
 602'GIT_OBJECT_DIRECTORY'::
 603        If the object storage directory is specified via this
 604        environment variable then the sha1 directories are created
 605        underneath - otherwise the default `$GIT_DIR/objects`
 606        directory is used.
 607
 608'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
 609        Due to the immutable nature of git objects, old objects can be
 610        archived into shared, read-only directories. This variable
 611        specifies a ":" separated (on Windows ";" separated) list
 612        of git object directories which can be used to search for git
 613        objects. New objects will not be written to these directories.
 614
 615'GIT_DIR'::
 616        If the 'GIT_DIR' environment variable is set then it
 617        specifies a path to use instead of the default `.git`
 618        for the base of the repository.
 619
 620'GIT_WORK_TREE'::
 621        Set the path to the working tree.  The value will not be
 622        used in combination with repositories found automatically in
 623        a .git directory (i.e. $GIT_DIR is not set).
 624        This can also be controlled by the '--work-tree' command line
 625        option and the core.worktree configuration variable.
 626
 627'GIT_NAMESPACE'::
 628        Set the git namespace; see linkgit:gitnamespaces[7] for details.
 629        The '--namespace' command-line option also sets this value.
 630
 631'GIT_CEILING_DIRECTORIES'::
 632        This should be a colon-separated list of absolute paths.
 633        If set, it is a list of directories that git should not chdir
 634        up into while looking for a repository directory.
 635        It will not exclude the current working directory or
 636        a GIT_DIR set on the command line or in the environment.
 637        (Useful for excluding slow-loading network directories.)
 638
 639'GIT_DISCOVERY_ACROSS_FILESYSTEM'::
 640        When run in a directory that does not have ".git" repository
 641        directory, git tries to find such a directory in the parent
 642        directories to find the top of the working tree, but by default it
 643        does not cross filesystem boundaries.  This environment variable
 644        can be set to true to tell git not to stop at filesystem
 645        boundaries.  Like 'GIT_CEILING_DIRECTORIES', this will not affect
 646        an explicit repository directory set via 'GIT_DIR' or on the
 647        command line.
 648
 649git Commits
 650~~~~~~~~~~~
 651'GIT_AUTHOR_NAME'::
 652'GIT_AUTHOR_EMAIL'::
 653'GIT_AUTHOR_DATE'::
 654'GIT_COMMITTER_NAME'::
 655'GIT_COMMITTER_EMAIL'::
 656'GIT_COMMITTER_DATE'::
 657'EMAIL'::
 658        see linkgit:git-commit-tree[1]
 659
 660git Diffs
 661~~~~~~~~~
 662'GIT_DIFF_OPTS'::
 663        Only valid setting is "--unified=??" or "-u??" to set the
 664        number of context lines shown when a unified diff is created.
 665        This takes precedence over any "-U" or "--unified" option
 666        value passed on the git diff command line.
 667
 668'GIT_EXTERNAL_DIFF'::
 669        When the environment variable 'GIT_EXTERNAL_DIFF' is set, the
 670        program named by it is called, instead of the diff invocation
 671        described above.  For a path that is added, removed, or modified,
 672        'GIT_EXTERNAL_DIFF' is called with 7 parameters:
 673
 674        path old-file old-hex old-mode new-file new-hex new-mode
 675+
 676where:
 677
 678        <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the
 679                         contents of <old|new>,
 680        <old|new>-hex:: are the 40-hexdigit SHA1 hashes,
 681        <old|new>-mode:: are the octal representation of the file modes.
 682+
 683The file parameters can point at the user's working file
 684(e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
 685when a new file is added), or a temporary file (e.g. `old-file` in the
 686index).  'GIT_EXTERNAL_DIFF' should not worry about unlinking the
 687temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits.
 688+
 689For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1
 690parameter, <path>.
 691
 692other
 693~~~~~
 694'GIT_MERGE_VERBOSITY'::
 695        A number controlling the amount of output shown by
 696        the recursive merge strategy.  Overrides merge.verbosity.
 697        See linkgit:git-merge[1]
 698
 699'GIT_PAGER'::
 700        This environment variable overrides `$PAGER`. If it is set
 701        to an empty string or to the value "cat", git will not launch
 702        a pager.  See also the `core.pager` option in
 703        linkgit:git-config[1].
 704
 705'GIT_SSH'::
 706        If this environment variable is set then 'git fetch'
 707        and 'git push' will use this command instead
 708        of 'ssh' when they need to connect to a remote system.
 709        The '$GIT_SSH' command will be given exactly two arguments:
 710        the 'username@host' (or just 'host') from the URL and the
 711        shell command to execute on that remote system.
 712+
 713To pass options to the program that you want to list in GIT_SSH
 714you will need to wrap the program and options into a shell script,
 715then set GIT_SSH to refer to the shell script.
 716+
 717Usually it is easier to configure any desired options through your
 718personal `.ssh/config` file.  Please consult your ssh documentation
 719for further details.
 720
 721'GIT_ASKPASS'::
 722        If this environment variable is set, then git commands which need to
 723        acquire passwords or passphrases (e.g. for HTTP or IMAP authentication)
 724        will call this program with a suitable prompt as command line argument
 725        and read the password from its STDOUT. See also the 'core.askpass'
 726        option in linkgit:git-config[1].
 727
 728'GIT_FLUSH'::
 729        If this environment variable is set to "1", then commands such
 730        as 'git blame' (in incremental mode), 'git rev-list', 'git log',
 731        and 'git whatchanged' will force a flush of the output stream
 732        after each commit-oriented record have been flushed.   If this
 733        variable is set to "0", the output of these commands will be done
 734        using completely buffered I/O.   If this environment variable is
 735        not set, git will choose buffered or record-oriented flushing
 736        based on whether stdout appears to be redirected to a file or not.
 737
 738'GIT_TRACE'::
 739        If this variable is set to "1", "2" or "true" (comparison
 740        is case insensitive), git will print `trace:` messages on
 741        stderr telling about alias expansion, built-in command
 742        execution and external command execution.
 743        If this variable is set to an integer value greater than 1
 744        and lower than 10 (strictly) then git will interpret this
 745        value as an open file descriptor and will try to write the
 746        trace messages into this file descriptor.
 747        Alternatively, if this variable is set to an absolute path
 748        (starting with a '/' character), git will interpret this
 749        as a file path and will try to write the trace messages
 750        into it.
 751
 752Discussion[[Discussion]]
 753------------------------
 754
 755More detail on the following is available from the
 756link:user-manual.html#git-concepts[git concepts chapter of the
 757user-manual] and linkgit:gitcore-tutorial[7].
 758
 759A git project normally consists of a working directory with a ".git"
 760subdirectory at the top level.  The .git directory contains, among other
 761things, a compressed object database representing the complete history
 762of the project, an "index" file which links that history to the current
 763contents of the working tree, and named pointers into that history such
 764as tags and branch heads.
 765
 766The object database contains objects of three main types: blobs, which
 767hold file data; trees, which point to blobs and other trees to build up
 768directory hierarchies; and commits, which each reference a single tree
 769and some number of parent commits.
 770
 771The commit, equivalent to what other systems call a "changeset" or
 772"version", represents a step in the project's history, and each parent
 773represents an immediately preceding step.  Commits with more than one
 774parent represent merges of independent lines of development.
 775
 776All objects are named by the SHA1 hash of their contents, normally
 777written as a string of 40 hex digits.  Such names are globally unique.
 778The entire history leading up to a commit can be vouched for by signing
 779just that commit.  A fourth object type, the tag, is provided for this
 780purpose.
 781
 782When first created, objects are stored in individual files, but for
 783efficiency may later be compressed together into "pack files".
 784
 785Named pointers called refs mark interesting points in history.  A ref
 786may contain the SHA1 name of an object or the name of another ref.  Refs
 787with names beginning `ref/head/` contain the SHA1 name of the most
 788recent commit (or "head") of a branch under development.  SHA1 names of
 789tags of interest are stored under `ref/tags/`.  A special ref named
 790`HEAD` contains the name of the currently checked-out branch.
 791
 792The index file is initialized with a list of all paths and, for each
 793path, a blob object and a set of attributes.  The blob object represents
 794the contents of the file as of the head of the current branch.  The
 795attributes (last modified time, size, etc.) are taken from the
 796corresponding file in the working tree.  Subsequent changes to the
 797working tree can be found by comparing these attributes.  The index may
 798be updated with new content, and new commits may be created from the
 799content stored in the index.
 800
 801The index is also capable of storing multiple entries (called "stages")
 802for a given pathname.  These stages are used to hold the various
 803unmerged version of a file when a merge is in progress.
 804
 805Authors
 806-------
 807Git was started by Linus Torvalds, and is currently maintained by Junio
 808C Hamano. Numerous contributions have come from the git mailing list
 809<git@vger.kernel.org>. For a more complete list of contributors, see
 810http://git-scm.com/about. If you have a clone of git.git itself, the
 811output of linkgit:git-shortlog[1] and linkgit:git-blame[1] can show you
 812the authors for specific parts of the project.
 813
 814Reporting Bugs
 815--------------
 816
 817Report bugs to the Git mailing list <git@vger.kernel.org> where the
 818development and maintenance is primarily done.  You do not have to be
 819subscribed to the list to send a message there.
 820
 821SEE ALSO
 822--------
 823linkgit:gittutorial[7], linkgit:gittutorial-2[7],
 824link:everyday.html[Everyday Git], linkgit:gitcvs-migration[7],
 825linkgit:gitglossary[7], linkgit:gitcore-tutorial[7],
 826linkgit:gitcli[7], link:user-manual.html[The Git User's Manual],
 827linkgit:gitworkflows[7]
 828
 829GIT
 830---
 831Part of the linkgit:git[1] suite