Documentation / git.txton commit Merge branch 'js/compat-itimer' (067a1f5)
   1git(1)
   2======
   3
   4NAME
   5----
   6git - the stupid content tracker
   7
   8
   9SYNOPSIS
  10--------
  11[verse]
  12'git' [--version] [--help] [-c <name>=<value>]
  13    [--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]
  14    [-p|--paginate|--no-pager] [--no-replace-objects] [--bare]
  15    [--git-dir=<path>] [--work-tree=<path>] [--namespace=<name>]
  16    <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
  26commands.  The link:user-manual.html[Git User's Manual] has a more
  27in-depth introduction.
  28
  29After you mastered the basic concepts, you can come back to this
  30page to learn what commands git offers.  You can learn more about
  31individual git commands with "git help command".  linkgit:gitcli[7]
  32manual page gives you an overview of the command line command syntax.
  33
  34Formatted and hyperlinked version of the latest git documentation
  35can be viewed at `http://git-htmldocs.googlecode.com/git/git.html`.
  36
  37ifdef::stalenotes[]
  38[NOTE]
  39============
  40
  41You are reading the documentation for the latest (possibly
  42unreleased) version of git, that is available from 'master'
  43branch of the `git.git` repository.
  44Documentation for older releases are available here:
  45
  46* link:v1.7.12/git.html[documentation for release 1.7.12]
  47
  48* release notes for
  49  link:RelNotes/1.7.12.txt[1.7.12].
  50
  51* link:v1.7.11.6/git.html[documentation for release 1.7.11.6]
  52
  53* release notes for
  54  link:RelNotes/1.7.11.6.txt[1.7.11.6],
  55  link:RelNotes/1.7.11.5.txt[1.7.11.5],
  56  link:RelNotes/1.7.11.4.txt[1.7.11.4],
  57  link:RelNotes/1.7.11.3.txt[1.7.11.3],
  58  link:RelNotes/1.7.11.2.txt[1.7.11.2],
  59  link:RelNotes/1.7.11.1.txt[1.7.11.1],
  60  link:RelNotes/1.7.11.txt[1.7.11].
  61
  62* link:v1.7.10.5/git.html[documentation for release 1.7.10.5]
  63
  64* release notes for
  65  link:RelNotes/1.7.10.5.txt[1.7.10.5],
  66  link:RelNotes/1.7.10.4.txt[1.7.10.4],
  67  link:RelNotes/1.7.10.3.txt[1.7.10.3],
  68  link:RelNotes/1.7.10.2.txt[1.7.10.2],
  69  link:RelNotes/1.7.10.1.txt[1.7.10.1],
  70  link:RelNotes/1.7.10.txt[1.7.10].
  71
  72* link:v1.7.9.7/git.html[documentation for release 1.7.9.7]
  73
  74* release notes for
  75  link:RelNotes/1.7.9.7.txt[1.7.9.7],
  76  link:RelNotes/1.7.9.6.txt[1.7.9.6],
  77  link:RelNotes/1.7.9.5.txt[1.7.9.5],
  78  link:RelNotes/1.7.9.4.txt[1.7.9.4],
  79  link:RelNotes/1.7.9.3.txt[1.7.9.3],
  80  link:RelNotes/1.7.9.2.txt[1.7.9.2],
  81  link:RelNotes/1.7.9.1.txt[1.7.9.1],
  82  link:RelNotes/1.7.9.txt[1.7.9].
  83
  84* link:v1.7.8.6/git.html[documentation for release 1.7.8.6]
  85
  86* release notes for
  87  link:RelNotes/1.7.8.6.txt[1.7.8.6],
  88  link:RelNotes/1.7.8.5.txt[1.7.8.5],
  89  link:RelNotes/1.7.8.4.txt[1.7.8.4],
  90  link:RelNotes/1.7.8.3.txt[1.7.8.3],
  91  link:RelNotes/1.7.8.2.txt[1.7.8.2],
  92  link:RelNotes/1.7.8.1.txt[1.7.8.1],
  93  link:RelNotes/1.7.8.txt[1.7.8].
  94
  95* link:v1.7.7.7/git.html[documentation for release 1.7.7.7]
  96
  97* release notes for
  98  link:RelNotes/1.7.7.7.txt[1.7.7.7],
  99  link:RelNotes/1.7.7.6.txt[1.7.7.6],
 100  link:RelNotes/1.7.7.5.txt[1.7.7.5],
 101  link:RelNotes/1.7.7.4.txt[1.7.7.4],
 102  link:RelNotes/1.7.7.3.txt[1.7.7.3],
 103  link:RelNotes/1.7.7.2.txt[1.7.7.2],
 104  link:RelNotes/1.7.7.1.txt[1.7.7.1],
 105  link:RelNotes/1.7.7.txt[1.7.7].
 106
 107* link:v1.7.6.6/git.html[documentation for release 1.7.6.6]
 108
 109* release notes for
 110  link:RelNotes/1.7.6.6.txt[1.7.6.6],
 111  link:RelNotes/1.7.6.5.txt[1.7.6.5],
 112  link:RelNotes/1.7.6.4.txt[1.7.6.4],
 113  link:RelNotes/1.7.6.3.txt[1.7.6.3],
 114  link:RelNotes/1.7.6.2.txt[1.7.6.2],
 115  link:RelNotes/1.7.6.1.txt[1.7.6.1],
 116  link:RelNotes/1.7.6.txt[1.7.6].
 117
 118* link:v1.7.5.4/git.html[documentation for release 1.7.5.4]
 119
 120* release notes for
 121  link:RelNotes/1.7.5.4.txt[1.7.5.4],
 122  link:RelNotes/1.7.5.3.txt[1.7.5.3],
 123  link:RelNotes/1.7.5.2.txt[1.7.5.2],
 124  link:RelNotes/1.7.5.1.txt[1.7.5.1],
 125  link:RelNotes/1.7.5.txt[1.7.5].
 126
 127* link:v1.7.4.5/git.html[documentation for release 1.7.4.5]
 128
 129* release notes for
 130  link:RelNotes/1.7.4.5.txt[1.7.4.5],
 131  link:RelNotes/1.7.4.4.txt[1.7.4.4],
 132  link:RelNotes/1.7.4.3.txt[1.7.4.3],
 133  link:RelNotes/1.7.4.2.txt[1.7.4.2],
 134  link:RelNotes/1.7.4.1.txt[1.7.4.1],
 135  link:RelNotes/1.7.4.txt[1.7.4].
 136
 137* link:v1.7.3.5/git.html[documentation for release 1.7.3.5]
 138
 139* release notes for
 140  link:RelNotes/1.7.3.5.txt[1.7.3.5],
 141  link:RelNotes/1.7.3.4.txt[1.7.3.4],
 142  link:RelNotes/1.7.3.3.txt[1.7.3.3],
 143  link:RelNotes/1.7.3.2.txt[1.7.3.2],
 144  link:RelNotes/1.7.3.1.txt[1.7.3.1],
 145  link:RelNotes/1.7.3.txt[1.7.3].
 146
 147* link:v1.7.2.5/git.html[documentation for release 1.7.2.5]
 148
 149* release notes for
 150  link:RelNotes/1.7.2.5.txt[1.7.2.5],
 151  link:RelNotes/1.7.2.4.txt[1.7.2.4],
 152  link:RelNotes/1.7.2.3.txt[1.7.2.3],
 153  link:RelNotes/1.7.2.2.txt[1.7.2.2],
 154  link:RelNotes/1.7.2.1.txt[1.7.2.1],
 155  link:RelNotes/1.7.2.txt[1.7.2].
 156
 157* link:v1.7.1.4/git.html[documentation for release 1.7.1.4]
 158
 159* release notes for
 160  link:RelNotes/1.7.1.4.txt[1.7.1.4],
 161  link:RelNotes/1.7.1.3.txt[1.7.1.3],
 162  link:RelNotes/1.7.1.2.txt[1.7.1.2],
 163  link:RelNotes/1.7.1.1.txt[1.7.1.1],
 164  link:RelNotes/1.7.1.txt[1.7.1].
 165
 166* link:v1.7.0.9/git.html[documentation for release 1.7.0.9]
 167
 168* release notes for
 169  link:RelNotes/1.7.0.9.txt[1.7.0.9],
 170  link:RelNotes/1.7.0.8.txt[1.7.0.8],
 171  link:RelNotes/1.7.0.7.txt[1.7.0.7],
 172  link:RelNotes/1.7.0.6.txt[1.7.0.6],
 173  link:RelNotes/1.7.0.5.txt[1.7.0.5],
 174  link:RelNotes/1.7.0.4.txt[1.7.0.4],
 175  link:RelNotes/1.7.0.3.txt[1.7.0.3],
 176  link:RelNotes/1.7.0.2.txt[1.7.0.2],
 177  link:RelNotes/1.7.0.1.txt[1.7.0.1],
 178  link:RelNotes/1.7.0.txt[1.7.0].
 179
 180* link:v1.6.6.3/git.html[documentation for release 1.6.6.3]
 181
 182* release notes for
 183  link:RelNotes/1.6.6.3.txt[1.6.6.3],
 184  link:RelNotes/1.6.6.2.txt[1.6.6.2],
 185  link:RelNotes/1.6.6.1.txt[1.6.6.1],
 186  link:RelNotes/1.6.6.txt[1.6.6].
 187
 188* link:v1.6.5.9/git.html[documentation for release 1.6.5.9]
 189
 190* release notes for
 191  link:RelNotes/1.6.5.9.txt[1.6.5.9],
 192  link:RelNotes/1.6.5.8.txt[1.6.5.8],
 193  link:RelNotes/1.6.5.7.txt[1.6.5.7],
 194  link:RelNotes/1.6.5.6.txt[1.6.5.6],
 195  link:RelNotes/1.6.5.5.txt[1.6.5.5],
 196  link:RelNotes/1.6.5.4.txt[1.6.5.4],
 197  link:RelNotes/1.6.5.3.txt[1.6.5.3],
 198  link:RelNotes/1.6.5.2.txt[1.6.5.2],
 199  link:RelNotes/1.6.5.1.txt[1.6.5.1],
 200  link:RelNotes/1.6.5.txt[1.6.5].
 201
 202* link:v1.6.4.5/git.html[documentation for release 1.6.4.5]
 203
 204* release notes for
 205  link:RelNotes/1.6.4.5.txt[1.6.4.5],
 206  link:RelNotes/1.6.4.4.txt[1.6.4.4],
 207  link:RelNotes/1.6.4.3.txt[1.6.4.3],
 208  link:RelNotes/1.6.4.2.txt[1.6.4.2],
 209  link:RelNotes/1.6.4.1.txt[1.6.4.1],
 210  link:RelNotes/1.6.4.txt[1.6.4].
 211
 212* link:v1.6.3.4/git.html[documentation for release 1.6.3.4]
 213
 214* release notes for
 215  link:RelNotes/1.6.3.4.txt[1.6.3.4],
 216  link:RelNotes/1.6.3.3.txt[1.6.3.3],
 217  link:RelNotes/1.6.3.2.txt[1.6.3.2],
 218  link:RelNotes/1.6.3.1.txt[1.6.3.1],
 219  link:RelNotes/1.6.3.txt[1.6.3].
 220
 221* release notes for
 222  link:RelNotes/1.6.2.5.txt[1.6.2.5],
 223  link:RelNotes/1.6.2.4.txt[1.6.2.4],
 224  link:RelNotes/1.6.2.3.txt[1.6.2.3],
 225  link:RelNotes/1.6.2.2.txt[1.6.2.2],
 226  link:RelNotes/1.6.2.1.txt[1.6.2.1],
 227  link:RelNotes/1.6.2.txt[1.6.2].
 228
 229* link:v1.6.1.3/git.html[documentation for release 1.6.1.3]
 230
 231* release notes for
 232  link:RelNotes/1.6.1.3.txt[1.6.1.3],
 233  link:RelNotes/1.6.1.2.txt[1.6.1.2],
 234  link:RelNotes/1.6.1.1.txt[1.6.1.1],
 235  link:RelNotes/1.6.1.txt[1.6.1].
 236
 237* link:v1.6.0.6/git.html[documentation for release 1.6.0.6]
 238
 239* release notes for
 240  link:RelNotes/1.6.0.6.txt[1.6.0.6],
 241  link:RelNotes/1.6.0.5.txt[1.6.0.5],
 242  link:RelNotes/1.6.0.4.txt[1.6.0.4],
 243  link:RelNotes/1.6.0.3.txt[1.6.0.3],
 244  link:RelNotes/1.6.0.2.txt[1.6.0.2],
 245  link:RelNotes/1.6.0.1.txt[1.6.0.1],
 246  link:RelNotes/1.6.0.txt[1.6.0].
 247
 248* link:v1.5.6.6/git.html[documentation for release 1.5.6.6]
 249
 250* release notes for
 251  link:RelNotes/1.5.6.6.txt[1.5.6.6],
 252  link:RelNotes/1.5.6.5.txt[1.5.6.5],
 253  link:RelNotes/1.5.6.4.txt[1.5.6.4],
 254  link:RelNotes/1.5.6.3.txt[1.5.6.3],
 255  link:RelNotes/1.5.6.2.txt[1.5.6.2],
 256  link:RelNotes/1.5.6.1.txt[1.5.6.1],
 257  link:RelNotes/1.5.6.txt[1.5.6].
 258
 259* link:v1.5.5.6/git.html[documentation for release 1.5.5.6]
 260
 261* release notes for
 262  link:RelNotes/1.5.5.6.txt[1.5.5.6],
 263  link:RelNotes/1.5.5.5.txt[1.5.5.5],
 264  link:RelNotes/1.5.5.4.txt[1.5.5.4],
 265  link:RelNotes/1.5.5.3.txt[1.5.5.3],
 266  link:RelNotes/1.5.5.2.txt[1.5.5.2],
 267  link:RelNotes/1.5.5.1.txt[1.5.5.1],
 268  link:RelNotes/1.5.5.txt[1.5.5].
 269
 270* link:v1.5.4.7/git.html[documentation for release 1.5.4.7]
 271
 272* release notes for
 273  link:RelNotes/1.5.4.7.txt[1.5.4.7],
 274  link:RelNotes/1.5.4.6.txt[1.5.4.6],
 275  link:RelNotes/1.5.4.5.txt[1.5.4.5],
 276  link:RelNotes/1.5.4.4.txt[1.5.4.4],
 277  link:RelNotes/1.5.4.3.txt[1.5.4.3],
 278  link:RelNotes/1.5.4.2.txt[1.5.4.2],
 279  link:RelNotes/1.5.4.1.txt[1.5.4.1],
 280  link:RelNotes/1.5.4.txt[1.5.4].
 281
 282* link:v1.5.3.8/git.html[documentation for release 1.5.3.8]
 283
 284* release notes for
 285  link:RelNotes/1.5.3.8.txt[1.5.3.8],
 286  link:RelNotes/1.5.3.7.txt[1.5.3.7],
 287  link:RelNotes/1.5.3.6.txt[1.5.3.6],
 288  link:RelNotes/1.5.3.5.txt[1.5.3.5],
 289  link:RelNotes/1.5.3.4.txt[1.5.3.4],
 290  link:RelNotes/1.5.3.3.txt[1.5.3.3],
 291  link:RelNotes/1.5.3.2.txt[1.5.3.2],
 292  link:RelNotes/1.5.3.1.txt[1.5.3.1],
 293  link:RelNotes/1.5.3.txt[1.5.3].
 294
 295* link:v1.5.2.5/git.html[documentation for release 1.5.2.5]
 296
 297* release notes for
 298  link:RelNotes/1.5.2.5.txt[1.5.2.5],
 299  link:RelNotes/1.5.2.4.txt[1.5.2.4],
 300  link:RelNotes/1.5.2.3.txt[1.5.2.3],
 301  link:RelNotes/1.5.2.2.txt[1.5.2.2],
 302  link:RelNotes/1.5.2.1.txt[1.5.2.1],
 303  link:RelNotes/1.5.2.txt[1.5.2].
 304
 305* link:v1.5.1.6/git.html[documentation for release 1.5.1.6]
 306
 307* release notes for
 308  link:RelNotes/1.5.1.6.txt[1.5.1.6],
 309  link:RelNotes/1.5.1.5.txt[1.5.1.5],
 310  link:RelNotes/1.5.1.4.txt[1.5.1.4],
 311  link:RelNotes/1.5.1.3.txt[1.5.1.3],
 312  link:RelNotes/1.5.1.2.txt[1.5.1.2],
 313  link:RelNotes/1.5.1.1.txt[1.5.1.1],
 314  link:RelNotes/1.5.1.txt[1.5.1].
 315
 316* link:v1.5.0.7/git.html[documentation for release 1.5.0.7]
 317
 318* release notes for
 319  link:RelNotes/1.5.0.7.txt[1.5.0.7],
 320  link:RelNotes/1.5.0.6.txt[1.5.0.6],
 321  link:RelNotes/1.5.0.5.txt[1.5.0.5],
 322  link:RelNotes/1.5.0.3.txt[1.5.0.3],
 323  link:RelNotes/1.5.0.2.txt[1.5.0.2],
 324  link:RelNotes/1.5.0.1.txt[1.5.0.1],
 325  link:RelNotes/1.5.0.txt[1.5.0].
 326
 327* documentation for release link:v1.4.4.4/git.html[1.4.4.4],
 328  link:v1.3.3/git.html[1.3.3],
 329  link:v1.2.6/git.html[1.2.6],
 330  link:v1.0.13/git.html[1.0.13].
 331
 332============
 333
 334endif::stalenotes[]
 335
 336OPTIONS
 337-------
 338--version::
 339        Prints the git suite version that the 'git' program came from.
 340
 341--help::
 342        Prints the synopsis and a list of the most commonly used
 343        commands. If the option '--all' or '-a' is given then all
 344        available commands are printed. If a git command is named this
 345        option will bring up the manual page for that command.
 346+
 347Other options are available to control how the manual page is
 348displayed. See linkgit:git-help[1] for more information,
 349because `git --help ...` is converted internally into `git
 350help ...`.
 351
 352-c <name>=<value>::
 353        Pass a configuration parameter to the command. The value
 354        given will override values from configuration files.
 355        The <name> is expected in the same format as listed by
 356        'git config' (subkeys separated by dots).
 357
 358--exec-path[=<path>]::
 359        Path to wherever your core git programs are installed.
 360        This can also be controlled by setting the GIT_EXEC_PATH
 361        environment variable. If no path is given, 'git' will print
 362        the current setting and then exit.
 363
 364--html-path::
 365        Print the path, without trailing slash, where git's HTML
 366        documentation is installed and exit.
 367
 368--man-path::
 369        Print the manpath (see `man(1)`) for the man pages for
 370        this version of git and exit.
 371
 372--info-path::
 373        Print the path where the Info files documenting this
 374        version of git are installed and exit.
 375
 376-p::
 377--paginate::
 378        Pipe all output into 'less' (or if set, $PAGER) if standard
 379        output is a terminal.  This overrides the `pager.<cmd>`
 380        configuration options (see the "Configuration Mechanism" section
 381        below).
 382
 383--no-pager::
 384        Do not pipe git output into a pager.
 385
 386--git-dir=<path>::
 387        Set the path to the repository. This can also be controlled by
 388        setting the GIT_DIR environment variable. It can be an absolute
 389        path or relative path to current working directory.
 390
 391--work-tree=<path>::
 392        Set the path to the working tree. It can be an absolute path
 393        or a path relative to the current working directory.
 394        This can also be controlled by setting the GIT_WORK_TREE
 395        environment variable and the core.worktree configuration
 396        variable (see core.worktree in linkgit:git-config[1] for a
 397        more detailed discussion).
 398
 399--namespace=<path>::
 400        Set the git namespace.  See linkgit:gitnamespaces[7] for more
 401        details.  Equivalent to setting the `GIT_NAMESPACE` environment
 402        variable.
 403
 404--bare::
 405        Treat the repository as a bare repository.  If GIT_DIR
 406        environment is not set, it is set to the current working
 407        directory.
 408
 409--no-replace-objects::
 410        Do not use replacement refs to replace git objects. See
 411        linkgit:git-replace[1] for more information.
 412
 413
 414GIT COMMANDS
 415------------
 416
 417We divide git into high level ("porcelain") commands and low level
 418("plumbing") commands.
 419
 420High-level commands (porcelain)
 421-------------------------------
 422
 423We separate the porcelain commands into the main commands and some
 424ancillary user utilities.
 425
 426Main porcelain commands
 427~~~~~~~~~~~~~~~~~~~~~~~
 428
 429include::cmds-mainporcelain.txt[]
 430
 431Ancillary Commands
 432~~~~~~~~~~~~~~~~~~
 433Manipulators:
 434
 435include::cmds-ancillarymanipulators.txt[]
 436
 437Interrogators:
 438
 439include::cmds-ancillaryinterrogators.txt[]
 440
 441
 442Interacting with Others
 443~~~~~~~~~~~~~~~~~~~~~~~
 444
 445These commands are to interact with foreign SCM and with other
 446people via patch over e-mail.
 447
 448include::cmds-foreignscminterface.txt[]
 449
 450
 451Low-level commands (plumbing)
 452-----------------------------
 453
 454Although git includes its
 455own porcelain layer, its low-level commands are sufficient to support
 456development of alternative porcelains.  Developers of such porcelains
 457might start by reading about linkgit:git-update-index[1] and
 458linkgit:git-read-tree[1].
 459
 460The interface (input, output, set of options and the semantics)
 461to these low-level commands are meant to be a lot more stable
 462than Porcelain level commands, because these commands are
 463primarily for scripted use.  The interface to Porcelain commands
 464on the other hand are subject to change in order to improve the
 465end user experience.
 466
 467The following description divides
 468the low-level commands into commands that manipulate objects (in
 469the repository, index, and working tree), commands that interrogate and
 470compare objects, and commands that move objects and references between
 471repositories.
 472
 473
 474Manipulation commands
 475~~~~~~~~~~~~~~~~~~~~~
 476
 477include::cmds-plumbingmanipulators.txt[]
 478
 479
 480Interrogation commands
 481~~~~~~~~~~~~~~~~~~~~~~
 482
 483include::cmds-plumbinginterrogators.txt[]
 484
 485In general, the interrogate commands do not touch the files in
 486the working tree.
 487
 488
 489Synching repositories
 490~~~~~~~~~~~~~~~~~~~~~
 491
 492include::cmds-synchingrepositories.txt[]
 493
 494The following are helper commands used by the above; end users
 495typically do not use them directly.
 496
 497include::cmds-synchelpers.txt[]
 498
 499
 500Internal helper commands
 501~~~~~~~~~~~~~~~~~~~~~~~~
 502
 503These are internal helper commands used by other commands; end
 504users typically do not use them directly.
 505
 506include::cmds-purehelpers.txt[]
 507
 508
 509Configuration Mechanism
 510-----------------------
 511
 512Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file
 513is used to hold per-repository configuration options.  It is a
 514simple text file modeled after `.ini` format familiar to some
 515people.  Here is an example:
 516
 517------------
 518#
 519# A '#' or ';' character indicates a comment.
 520#
 521
 522; core variables
 523[core]
 524        ; Don't trust file modes
 525        filemode = false
 526
 527; user identity
 528[user]
 529        name = "Junio C Hamano"
 530        email = "junkio@twinsun.com"
 531
 532------------
 533
 534Various commands read from the configuration file and adjust
 535their operation accordingly.  See linkgit:git-config[1] for a
 536list.
 537
 538
 539Identifier Terminology
 540----------------------
 541<object>::
 542        Indicates the object name for any type of object.
 543
 544<blob>::
 545        Indicates a blob object name.
 546
 547<tree>::
 548        Indicates a tree object name.
 549
 550<commit>::
 551        Indicates a commit object name.
 552
 553<tree-ish>::
 554        Indicates a tree, commit or tag object name.  A
 555        command that takes a <tree-ish> argument ultimately wants to
 556        operate on a <tree> object but automatically dereferences
 557        <commit> and <tag> objects that point at a <tree>.
 558
 559<commit-ish>::
 560        Indicates a commit or tag object name.  A
 561        command that takes a <commit-ish> argument ultimately wants to
 562        operate on a <commit> object but automatically dereferences
 563        <tag> objects that point at a <commit>.
 564
 565<type>::
 566        Indicates that an object type is required.
 567        Currently one of: `blob`, `tree`, `commit`, or `tag`.
 568
 569<file>::
 570        Indicates a filename - almost always relative to the
 571        root of the tree structure `GIT_INDEX_FILE` describes.
 572
 573Symbolic Identifiers
 574--------------------
 575Any git command accepting any <object> can also use the following
 576symbolic notation:
 577
 578HEAD::
 579        indicates the head of the current branch.
 580
 581<tag>::
 582        a valid tag 'name'
 583        (i.e. a `refs/tags/<tag>` reference).
 584
 585<head>::
 586        a valid head 'name'
 587        (i.e. a `refs/heads/<head>` reference).
 588
 589For a more complete list of ways to spell object names, see
 590"SPECIFYING REVISIONS" section in linkgit:gitrevisions[7].
 591
 592
 593File/Directory Structure
 594------------------------
 595
 596Please see the linkgit:gitrepository-layout[5] document.
 597
 598Read linkgit:githooks[5] for more details about each hook.
 599
 600Higher level SCMs may provide and manage additional information in the
 601`$GIT_DIR`.
 602
 603
 604Terminology
 605-----------
 606Please see linkgit:gitglossary[7].
 607
 608
 609Environment Variables
 610---------------------
 611Various git commands use the following environment variables:
 612
 613The git Repository
 614~~~~~~~~~~~~~~~~~~
 615These environment variables apply to 'all' core git commands. Nb: it
 616is worth noting that they may be used/overridden by SCMS sitting above
 617git so take care if using Cogito etc.
 618
 619'GIT_INDEX_FILE'::
 620        This environment allows the specification of an alternate
 621        index file. If not specified, the default of `$GIT_DIR/index`
 622        is used.
 623
 624'GIT_OBJECT_DIRECTORY'::
 625        If the object storage directory is specified via this
 626        environment variable then the sha1 directories are created
 627        underneath - otherwise the default `$GIT_DIR/objects`
 628        directory is used.
 629
 630'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
 631        Due to the immutable nature of git objects, old objects can be
 632        archived into shared, read-only directories. This variable
 633        specifies a ":" separated (on Windows ";" separated) list
 634        of git object directories which can be used to search for git
 635        objects. New objects will not be written to these directories.
 636
 637'GIT_DIR'::
 638        If the 'GIT_DIR' environment variable is set then it
 639        specifies a path to use instead of the default `.git`
 640        for the base of the repository.
 641
 642'GIT_WORK_TREE'::
 643        Set the path to the working tree.  The value will not be
 644        used in combination with repositories found automatically in
 645        a .git directory (i.e. $GIT_DIR is not set).
 646        This can also be controlled by the '--work-tree' command line
 647        option and the core.worktree configuration variable.
 648
 649'GIT_NAMESPACE'::
 650        Set the git namespace; see linkgit:gitnamespaces[7] for details.
 651        The '--namespace' command-line option also sets this value.
 652
 653'GIT_CEILING_DIRECTORIES'::
 654        This should be a colon-separated list of absolute paths.
 655        If set, it is a list of directories that git should not chdir
 656        up into while looking for a repository directory.
 657        It will not exclude the current working directory or
 658        a GIT_DIR set on the command line or in the environment.
 659        (Useful for excluding slow-loading network directories.)
 660
 661'GIT_DISCOVERY_ACROSS_FILESYSTEM'::
 662        When run in a directory that does not have ".git" repository
 663        directory, git tries to find such a directory in the parent
 664        directories to find the top of the working tree, but by default it
 665        does not cross filesystem boundaries.  This environment variable
 666        can be set to true to tell git not to stop at filesystem
 667        boundaries.  Like 'GIT_CEILING_DIRECTORIES', this will not affect
 668        an explicit repository directory set via 'GIT_DIR' or on the
 669        command line.
 670
 671git Commits
 672~~~~~~~~~~~
 673'GIT_AUTHOR_NAME'::
 674'GIT_AUTHOR_EMAIL'::
 675'GIT_AUTHOR_DATE'::
 676'GIT_COMMITTER_NAME'::
 677'GIT_COMMITTER_EMAIL'::
 678'GIT_COMMITTER_DATE'::
 679'EMAIL'::
 680        see linkgit:git-commit-tree[1]
 681
 682git Diffs
 683~~~~~~~~~
 684'GIT_DIFF_OPTS'::
 685        Only valid setting is "--unified=??" or "-u??" to set the
 686        number of context lines shown when a unified diff is created.
 687        This takes precedence over any "-U" or "--unified" option
 688        value passed on the git diff command line.
 689
 690'GIT_EXTERNAL_DIFF'::
 691        When the environment variable 'GIT_EXTERNAL_DIFF' is set, the
 692        program named by it is called, instead of the diff invocation
 693        described above.  For a path that is added, removed, or modified,
 694        'GIT_EXTERNAL_DIFF' is called with 7 parameters:
 695
 696        path old-file old-hex old-mode new-file new-hex new-mode
 697+
 698where:
 699
 700        <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the
 701                         contents of <old|new>,
 702        <old|new>-hex:: are the 40-hexdigit SHA1 hashes,
 703        <old|new>-mode:: are the octal representation of the file modes.
 704+
 705The file parameters can point at the user's working file
 706(e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
 707when a new file is added), or a temporary file (e.g. `old-file` in the
 708index).  'GIT_EXTERNAL_DIFF' should not worry about unlinking the
 709temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits.
 710+
 711For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1
 712parameter, <path>.
 713
 714other
 715~~~~~
 716'GIT_MERGE_VERBOSITY'::
 717        A number controlling the amount of output shown by
 718        the recursive merge strategy.  Overrides merge.verbosity.
 719        See linkgit:git-merge[1]
 720
 721'GIT_PAGER'::
 722        This environment variable overrides `$PAGER`. If it is set
 723        to an empty string or to the value "cat", git will not launch
 724        a pager.  See also the `core.pager` option in
 725        linkgit:git-config[1].
 726
 727'GIT_EDITOR'::
 728        This environment variable overrides `$EDITOR` and `$VISUAL`.
 729        It is used by several git commands when, on interactive mode,
 730        an editor is to be launched. See also linkgit:git-var[1]
 731        and the `core.editor` option in linkgit:git-config[1].
 732
 733'GIT_SSH'::
 734        If this environment variable is set then 'git fetch'
 735        and 'git push' will use this command instead
 736        of 'ssh' when they need to connect to a remote system.
 737        The '$GIT_SSH' command will be given exactly two arguments:
 738        the 'username@host' (or just 'host') from the URL and the
 739        shell command to execute on that remote system.
 740+
 741To pass options to the program that you want to list in GIT_SSH
 742you will need to wrap the program and options into a shell script,
 743then set GIT_SSH to refer to the shell script.
 744+
 745Usually it is easier to configure any desired options through your
 746personal `.ssh/config` file.  Please consult your ssh documentation
 747for further details.
 748
 749'GIT_ASKPASS'::
 750        If this environment variable is set, then git commands which need to
 751        acquire passwords or passphrases (e.g. for HTTP or IMAP authentication)
 752        will call this program with a suitable prompt as command line argument
 753        and read the password from its STDOUT. See also the 'core.askpass'
 754        option in linkgit:git-config[1].
 755
 756'GIT_FLUSH'::
 757        If this environment variable is set to "1", then commands such
 758        as 'git blame' (in incremental mode), 'git rev-list', 'git log',
 759        and 'git whatchanged' will force a flush of the output stream
 760        after each commit-oriented record have been flushed.   If this
 761        variable is set to "0", the output of these commands will be done
 762        using completely buffered I/O.   If this environment variable is
 763        not set, git will choose buffered or record-oriented flushing
 764        based on whether stdout appears to be redirected to a file or not.
 765
 766'GIT_TRACE'::
 767        If this variable is set to "1", "2" or "true" (comparison
 768        is case insensitive), git will print `trace:` messages on
 769        stderr telling about alias expansion, built-in command
 770        execution and external command execution.
 771        If this variable is set to an integer value greater than 1
 772        and lower than 10 (strictly) then git will interpret this
 773        value as an open file descriptor and will try to write the
 774        trace messages into this file descriptor.
 775        Alternatively, if this variable is set to an absolute path
 776        (starting with a '/' character), git will interpret this
 777        as a file path and will try to write the trace messages
 778        into it.
 779
 780Discussion[[Discussion]]
 781------------------------
 782
 783More detail on the following is available from the
 784link:user-manual.html#git-concepts[git concepts chapter of the
 785user-manual] and linkgit:gitcore-tutorial[7].
 786
 787A git project normally consists of a working directory with a ".git"
 788subdirectory at the top level.  The .git directory contains, among other
 789things, a compressed object database representing the complete history
 790of the project, an "index" file which links that history to the current
 791contents of the working tree, and named pointers into that history such
 792as tags and branch heads.
 793
 794The object database contains objects of three main types: blobs, which
 795hold file data; trees, which point to blobs and other trees to build up
 796directory hierarchies; and commits, which each reference a single tree
 797and some number of parent commits.
 798
 799The commit, equivalent to what other systems call a "changeset" or
 800"version", represents a step in the project's history, and each parent
 801represents an immediately preceding step.  Commits with more than one
 802parent represent merges of independent lines of development.
 803
 804All objects are named by the SHA1 hash of their contents, normally
 805written as a string of 40 hex digits.  Such names are globally unique.
 806The entire history leading up to a commit can be vouched for by signing
 807just that commit.  A fourth object type, the tag, is provided for this
 808purpose.
 809
 810When first created, objects are stored in individual files, but for
 811efficiency may later be compressed together into "pack files".
 812
 813Named pointers called refs mark interesting points in history.  A ref
 814may contain the SHA1 name of an object or the name of another ref.  Refs
 815with names beginning `ref/head/` contain the SHA1 name of the most
 816recent commit (or "head") of a branch under development.  SHA1 names of
 817tags of interest are stored under `ref/tags/`.  A special ref named
 818`HEAD` contains the name of the currently checked-out branch.
 819
 820The index file is initialized with a list of all paths and, for each
 821path, a blob object and a set of attributes.  The blob object represents
 822the contents of the file as of the head of the current branch.  The
 823attributes (last modified time, size, etc.) are taken from the
 824corresponding file in the working tree.  Subsequent changes to the
 825working tree can be found by comparing these attributes.  The index may
 826be updated with new content, and new commits may be created from the
 827content stored in the index.
 828
 829The index is also capable of storing multiple entries (called "stages")
 830for a given pathname.  These stages are used to hold the various
 831unmerged version of a file when a merge is in progress.
 832
 833FURTHER DOCUMENTATION
 834---------------------
 835
 836See the references in the "description" section to get started
 837using git.  The following is probably more detail than necessary
 838for a first-time user.
 839
 840The link:user-manual.html#git-concepts[git concepts chapter of the
 841user-manual] and linkgit:gitcore-tutorial[7] both provide
 842introductions to the underlying git architecture.
 843
 844See linkgit:gitworkflows[7] for an overview of recommended workflows.
 845
 846See also the link:howto-index.html[howto] documents for some useful
 847examples.
 848
 849The internals are documented in the
 850link:technical/api-index.html[GIT API documentation].
 851
 852Users migrating from CVS may also want to
 853read linkgit:gitcvs-migration[7].
 854
 855
 856Authors
 857-------
 858Git was started by Linus Torvalds, and is currently maintained by Junio
 859C Hamano. Numerous contributions have come from the git mailing list
 860<git@vger.kernel.org>. For a more complete list of contributors, see
 861http://git-scm.com/about. If you have a clone of git.git itself, the
 862output of linkgit:git-shortlog[1] and linkgit:git-blame[1] can show you
 863the authors for specific parts of the project.
 864
 865Reporting Bugs
 866--------------
 867
 868Report bugs to the Git mailing list <git@vger.kernel.org> where the
 869development and maintenance is primarily done.  You do not have to be
 870subscribed to the list to send a message there.
 871
 872SEE ALSO
 873--------
 874linkgit:gittutorial[7], linkgit:gittutorial-2[7],
 875link:everyday.html[Everyday Git], linkgit:gitcvs-migration[7],
 876linkgit:gitglossary[7], linkgit:gitcore-tutorial[7],
 877linkgit:gitcli[7], link:user-manual.html[The Git User's Manual],
 878linkgit:gitworkflows[7]
 879
 880GIT
 881---
 882Part of the linkgit:git[1] suite