Documentation / git.txton commit Merge branch 'jh/update-ref-d-through-symref' into maint (ed20513)
   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:v1.8.0.1/git.html[documentation for release 1.8.0.1]
  47
  48* release notes for
  49  link:RelNotes/1.8.0.1.txt[1.8.0.1],
  50  link:RelNotes/1.8.0.txt[1.8.0].
  51
  52* link:v1.7.12.4/git.html[documentation for release 1.7.12.4]
  53
  54* release notes for
  55  link:RelNotes/1.7.12.4.txt[1.7.12.4],
  56  link:RelNotes/1.7.12.3.txt[1.7.12.3],
  57  link:RelNotes/1.7.12.2.txt[1.7.12.2],
  58  link:RelNotes/1.7.12.1.txt[1.7.12.1],
  59  link:RelNotes/1.7.12.txt[1.7.12].
  60
  61* link:v1.7.11.7/git.html[documentation for release 1.7.11.7]
  62
  63* release notes for
  64  link:RelNotes/1.7.11.7.txt[1.7.11.7],
  65  link:RelNotes/1.7.11.6.txt[1.7.11.6],
  66  link:RelNotes/1.7.11.5.txt[1.7.11.5],
  67  link:RelNotes/1.7.11.4.txt[1.7.11.4],
  68  link:RelNotes/1.7.11.3.txt[1.7.11.3],
  69  link:RelNotes/1.7.11.2.txt[1.7.11.2],
  70  link:RelNotes/1.7.11.1.txt[1.7.11.1],
  71  link:RelNotes/1.7.11.txt[1.7.11].
  72
  73* link:v1.7.10.5/git.html[documentation for release 1.7.10.5]
  74
  75* release notes for
  76  link:RelNotes/1.7.10.5.txt[1.7.10.5],
  77  link:RelNotes/1.7.10.4.txt[1.7.10.4],
  78  link:RelNotes/1.7.10.3.txt[1.7.10.3],
  79  link:RelNotes/1.7.10.2.txt[1.7.10.2],
  80  link:RelNotes/1.7.10.1.txt[1.7.10.1],
  81  link:RelNotes/1.7.10.txt[1.7.10].
  82
  83* link:v1.7.9.7/git.html[documentation for release 1.7.9.7]
  84
  85* release notes for
  86  link:RelNotes/1.7.9.7.txt[1.7.9.7],
  87  link:RelNotes/1.7.9.6.txt[1.7.9.6],
  88  link:RelNotes/1.7.9.5.txt[1.7.9.5],
  89  link:RelNotes/1.7.9.4.txt[1.7.9.4],
  90  link:RelNotes/1.7.9.3.txt[1.7.9.3],
  91  link:RelNotes/1.7.9.2.txt[1.7.9.2],
  92  link:RelNotes/1.7.9.1.txt[1.7.9.1],
  93  link:RelNotes/1.7.9.txt[1.7.9].
  94
  95* link:v1.7.8.6/git.html[documentation for release 1.7.8.6]
  96
  97* release notes for
  98  link:RelNotes/1.7.8.6.txt[1.7.8.6],
  99  link:RelNotes/1.7.8.5.txt[1.7.8.5],
 100  link:RelNotes/1.7.8.4.txt[1.7.8.4],
 101  link:RelNotes/1.7.8.3.txt[1.7.8.3],
 102  link:RelNotes/1.7.8.2.txt[1.7.8.2],
 103  link:RelNotes/1.7.8.1.txt[1.7.8.1],
 104  link:RelNotes/1.7.8.txt[1.7.8].
 105
 106* link:v1.7.7.7/git.html[documentation for release 1.7.7.7]
 107
 108* release notes for
 109  link:RelNotes/1.7.7.7.txt[1.7.7.7],
 110  link:RelNotes/1.7.7.6.txt[1.7.7.6],
 111  link:RelNotes/1.7.7.5.txt[1.7.7.5],
 112  link:RelNotes/1.7.7.4.txt[1.7.7.4],
 113  link:RelNotes/1.7.7.3.txt[1.7.7.3],
 114  link:RelNotes/1.7.7.2.txt[1.7.7.2],
 115  link:RelNotes/1.7.7.1.txt[1.7.7.1],
 116  link:RelNotes/1.7.7.txt[1.7.7].
 117
 118* link:v1.7.6.6/git.html[documentation for release 1.7.6.6]
 119
 120* release notes for
 121  link:RelNotes/1.7.6.6.txt[1.7.6.6],
 122  link:RelNotes/1.7.6.5.txt[1.7.6.5],
 123  link:RelNotes/1.7.6.4.txt[1.7.6.4],
 124  link:RelNotes/1.7.6.3.txt[1.7.6.3],
 125  link:RelNotes/1.7.6.2.txt[1.7.6.2],
 126  link:RelNotes/1.7.6.1.txt[1.7.6.1],
 127  link:RelNotes/1.7.6.txt[1.7.6].
 128
 129* link:v1.7.5.4/git.html[documentation for release 1.7.5.4]
 130
 131* release notes for
 132  link:RelNotes/1.7.5.4.txt[1.7.5.4],
 133  link:RelNotes/1.7.5.3.txt[1.7.5.3],
 134  link:RelNotes/1.7.5.2.txt[1.7.5.2],
 135  link:RelNotes/1.7.5.1.txt[1.7.5.1],
 136  link:RelNotes/1.7.5.txt[1.7.5].
 137
 138* link:v1.7.4.5/git.html[documentation for release 1.7.4.5]
 139
 140* release notes for
 141  link:RelNotes/1.7.4.5.txt[1.7.4.5],
 142  link:RelNotes/1.7.4.4.txt[1.7.4.4],
 143  link:RelNotes/1.7.4.3.txt[1.7.4.3],
 144  link:RelNotes/1.7.4.2.txt[1.7.4.2],
 145  link:RelNotes/1.7.4.1.txt[1.7.4.1],
 146  link:RelNotes/1.7.4.txt[1.7.4].
 147
 148* link:v1.7.3.5/git.html[documentation for release 1.7.3.5]
 149
 150* release notes for
 151  link:RelNotes/1.7.3.5.txt[1.7.3.5],
 152  link:RelNotes/1.7.3.4.txt[1.7.3.4],
 153  link:RelNotes/1.7.3.3.txt[1.7.3.3],
 154  link:RelNotes/1.7.3.2.txt[1.7.3.2],
 155  link:RelNotes/1.7.3.1.txt[1.7.3.1],
 156  link:RelNotes/1.7.3.txt[1.7.3].
 157
 158* link:v1.7.2.5/git.html[documentation for release 1.7.2.5]
 159
 160* release notes for
 161  link:RelNotes/1.7.2.5.txt[1.7.2.5],
 162  link:RelNotes/1.7.2.4.txt[1.7.2.4],
 163  link:RelNotes/1.7.2.3.txt[1.7.2.3],
 164  link:RelNotes/1.7.2.2.txt[1.7.2.2],
 165  link:RelNotes/1.7.2.1.txt[1.7.2.1],
 166  link:RelNotes/1.7.2.txt[1.7.2].
 167
 168* link:v1.7.1.4/git.html[documentation for release 1.7.1.4]
 169
 170* release notes for
 171  link:RelNotes/1.7.1.4.txt[1.7.1.4],
 172  link:RelNotes/1.7.1.3.txt[1.7.1.3],
 173  link:RelNotes/1.7.1.2.txt[1.7.1.2],
 174  link:RelNotes/1.7.1.1.txt[1.7.1.1],
 175  link:RelNotes/1.7.1.txt[1.7.1].
 176
 177* link:v1.7.0.9/git.html[documentation for release 1.7.0.9]
 178
 179* release notes for
 180  link:RelNotes/1.7.0.9.txt[1.7.0.9],
 181  link:RelNotes/1.7.0.8.txt[1.7.0.8],
 182  link:RelNotes/1.7.0.7.txt[1.7.0.7],
 183  link:RelNotes/1.7.0.6.txt[1.7.0.6],
 184  link:RelNotes/1.7.0.5.txt[1.7.0.5],
 185  link:RelNotes/1.7.0.4.txt[1.7.0.4],
 186  link:RelNotes/1.7.0.3.txt[1.7.0.3],
 187  link:RelNotes/1.7.0.2.txt[1.7.0.2],
 188  link:RelNotes/1.7.0.1.txt[1.7.0.1],
 189  link:RelNotes/1.7.0.txt[1.7.0].
 190
 191* link:v1.6.6.3/git.html[documentation for release 1.6.6.3]
 192
 193* release notes for
 194  link:RelNotes/1.6.6.3.txt[1.6.6.3],
 195  link:RelNotes/1.6.6.2.txt[1.6.6.2],
 196  link:RelNotes/1.6.6.1.txt[1.6.6.1],
 197  link:RelNotes/1.6.6.txt[1.6.6].
 198
 199* link:v1.6.5.9/git.html[documentation for release 1.6.5.9]
 200
 201* release notes for
 202  link:RelNotes/1.6.5.9.txt[1.6.5.9],
 203  link:RelNotes/1.6.5.8.txt[1.6.5.8],
 204  link:RelNotes/1.6.5.7.txt[1.6.5.7],
 205  link:RelNotes/1.6.5.6.txt[1.6.5.6],
 206  link:RelNotes/1.6.5.5.txt[1.6.5.5],
 207  link:RelNotes/1.6.5.4.txt[1.6.5.4],
 208  link:RelNotes/1.6.5.3.txt[1.6.5.3],
 209  link:RelNotes/1.6.5.2.txt[1.6.5.2],
 210  link:RelNotes/1.6.5.1.txt[1.6.5.1],
 211  link:RelNotes/1.6.5.txt[1.6.5].
 212
 213* link:v1.6.4.5/git.html[documentation for release 1.6.4.5]
 214
 215* release notes for
 216  link:RelNotes/1.6.4.5.txt[1.6.4.5],
 217  link:RelNotes/1.6.4.4.txt[1.6.4.4],
 218  link:RelNotes/1.6.4.3.txt[1.6.4.3],
 219  link:RelNotes/1.6.4.2.txt[1.6.4.2],
 220  link:RelNotes/1.6.4.1.txt[1.6.4.1],
 221  link:RelNotes/1.6.4.txt[1.6.4].
 222
 223* link:v1.6.3.4/git.html[documentation for release 1.6.3.4]
 224
 225* release notes for
 226  link:RelNotes/1.6.3.4.txt[1.6.3.4],
 227  link:RelNotes/1.6.3.3.txt[1.6.3.3],
 228  link:RelNotes/1.6.3.2.txt[1.6.3.2],
 229  link:RelNotes/1.6.3.1.txt[1.6.3.1],
 230  link:RelNotes/1.6.3.txt[1.6.3].
 231
 232* release notes for
 233  link:RelNotes/1.6.2.5.txt[1.6.2.5],
 234  link:RelNotes/1.6.2.4.txt[1.6.2.4],
 235  link:RelNotes/1.6.2.3.txt[1.6.2.3],
 236  link:RelNotes/1.6.2.2.txt[1.6.2.2],
 237  link:RelNotes/1.6.2.1.txt[1.6.2.1],
 238  link:RelNotes/1.6.2.txt[1.6.2].
 239
 240* link:v1.6.1.3/git.html[documentation for release 1.6.1.3]
 241
 242* release notes for
 243  link:RelNotes/1.6.1.3.txt[1.6.1.3],
 244  link:RelNotes/1.6.1.2.txt[1.6.1.2],
 245  link:RelNotes/1.6.1.1.txt[1.6.1.1],
 246  link:RelNotes/1.6.1.txt[1.6.1].
 247
 248* link:v1.6.0.6/git.html[documentation for release 1.6.0.6]
 249
 250* release notes for
 251  link:RelNotes/1.6.0.6.txt[1.6.0.6],
 252  link:RelNotes/1.6.0.5.txt[1.6.0.5],
 253  link:RelNotes/1.6.0.4.txt[1.6.0.4],
 254  link:RelNotes/1.6.0.3.txt[1.6.0.3],
 255  link:RelNotes/1.6.0.2.txt[1.6.0.2],
 256  link:RelNotes/1.6.0.1.txt[1.6.0.1],
 257  link:RelNotes/1.6.0.txt[1.6.0].
 258
 259* link:v1.5.6.6/git.html[documentation for release 1.5.6.6]
 260
 261* release notes for
 262  link:RelNotes/1.5.6.6.txt[1.5.6.6],
 263  link:RelNotes/1.5.6.5.txt[1.5.6.5],
 264  link:RelNotes/1.5.6.4.txt[1.5.6.4],
 265  link:RelNotes/1.5.6.3.txt[1.5.6.3],
 266  link:RelNotes/1.5.6.2.txt[1.5.6.2],
 267  link:RelNotes/1.5.6.1.txt[1.5.6.1],
 268  link:RelNotes/1.5.6.txt[1.5.6].
 269
 270* link:v1.5.5.6/git.html[documentation for release 1.5.5.6]
 271
 272* release notes for
 273  link:RelNotes/1.5.5.6.txt[1.5.5.6],
 274  link:RelNotes/1.5.5.5.txt[1.5.5.5],
 275  link:RelNotes/1.5.5.4.txt[1.5.5.4],
 276  link:RelNotes/1.5.5.3.txt[1.5.5.3],
 277  link:RelNotes/1.5.5.2.txt[1.5.5.2],
 278  link:RelNotes/1.5.5.1.txt[1.5.5.1],
 279  link:RelNotes/1.5.5.txt[1.5.5].
 280
 281* link:v1.5.4.7/git.html[documentation for release 1.5.4.7]
 282
 283* release notes for
 284  link:RelNotes/1.5.4.7.txt[1.5.4.7],
 285  link:RelNotes/1.5.4.6.txt[1.5.4.6],
 286  link:RelNotes/1.5.4.5.txt[1.5.4.5],
 287  link:RelNotes/1.5.4.4.txt[1.5.4.4],
 288  link:RelNotes/1.5.4.3.txt[1.5.4.3],
 289  link:RelNotes/1.5.4.2.txt[1.5.4.2],
 290  link:RelNotes/1.5.4.1.txt[1.5.4.1],
 291  link:RelNotes/1.5.4.txt[1.5.4].
 292
 293* link:v1.5.3.8/git.html[documentation for release 1.5.3.8]
 294
 295* release notes for
 296  link:RelNotes/1.5.3.8.txt[1.5.3.8],
 297  link:RelNotes/1.5.3.7.txt[1.5.3.7],
 298  link:RelNotes/1.5.3.6.txt[1.5.3.6],
 299  link:RelNotes/1.5.3.5.txt[1.5.3.5],
 300  link:RelNotes/1.5.3.4.txt[1.5.3.4],
 301  link:RelNotes/1.5.3.3.txt[1.5.3.3],
 302  link:RelNotes/1.5.3.2.txt[1.5.3.2],
 303  link:RelNotes/1.5.3.1.txt[1.5.3.1],
 304  link:RelNotes/1.5.3.txt[1.5.3].
 305
 306* link:v1.5.2.5/git.html[documentation for release 1.5.2.5]
 307
 308* release notes for
 309  link:RelNotes/1.5.2.5.txt[1.5.2.5],
 310  link:RelNotes/1.5.2.4.txt[1.5.2.4],
 311  link:RelNotes/1.5.2.3.txt[1.5.2.3],
 312  link:RelNotes/1.5.2.2.txt[1.5.2.2],
 313  link:RelNotes/1.5.2.1.txt[1.5.2.1],
 314  link:RelNotes/1.5.2.txt[1.5.2].
 315
 316* link:v1.5.1.6/git.html[documentation for release 1.5.1.6]
 317
 318* release notes for
 319  link:RelNotes/1.5.1.6.txt[1.5.1.6],
 320  link:RelNotes/1.5.1.5.txt[1.5.1.5],
 321  link:RelNotes/1.5.1.4.txt[1.5.1.4],
 322  link:RelNotes/1.5.1.3.txt[1.5.1.3],
 323  link:RelNotes/1.5.1.2.txt[1.5.1.2],
 324  link:RelNotes/1.5.1.1.txt[1.5.1.1],
 325  link:RelNotes/1.5.1.txt[1.5.1].
 326
 327* link:v1.5.0.7/git.html[documentation for release 1.5.0.7]
 328
 329* release notes for
 330  link:RelNotes/1.5.0.7.txt[1.5.0.7],
 331  link:RelNotes/1.5.0.6.txt[1.5.0.6],
 332  link:RelNotes/1.5.0.5.txt[1.5.0.5],
 333  link:RelNotes/1.5.0.3.txt[1.5.0.3],
 334  link:RelNotes/1.5.0.2.txt[1.5.0.2],
 335  link:RelNotes/1.5.0.1.txt[1.5.0.1],
 336  link:RelNotes/1.5.0.txt[1.5.0].
 337
 338* documentation for release link:v1.4.4.4/git.html[1.4.4.4],
 339  link:v1.3.3/git.html[1.3.3],
 340  link:v1.2.6/git.html[1.2.6],
 341  link:v1.0.13/git.html[1.0.13].
 342
 343============
 344
 345endif::stalenotes[]
 346
 347OPTIONS
 348-------
 349--version::
 350        Prints the git suite version that the 'git' program came from.
 351
 352--help::
 353        Prints the synopsis and a list of the most commonly used
 354        commands. If the option '--all' or '-a' is given then all
 355        available commands are printed. If a git command is named this
 356        option will bring up the manual page for that command.
 357+
 358Other options are available to control how the manual page is
 359displayed. See linkgit:git-help[1] for more information,
 360because `git --help ...` is converted internally into `git
 361help ...`.
 362
 363-c <name>=<value>::
 364        Pass a configuration parameter to the command. The value
 365        given will override values from configuration files.
 366        The <name> is expected in the same format as listed by
 367        'git config' (subkeys separated by dots).
 368
 369--exec-path[=<path>]::
 370        Path to wherever your core git programs are installed.
 371        This can also be controlled by setting the GIT_EXEC_PATH
 372        environment variable. If no path is given, 'git' will print
 373        the current setting and then exit.
 374
 375--html-path::
 376        Print the path, without trailing slash, where git's HTML
 377        documentation is installed and exit.
 378
 379--man-path::
 380        Print the manpath (see `man(1)`) for the man pages for
 381        this version of git and exit.
 382
 383--info-path::
 384        Print the path where the Info files documenting this
 385        version of git are installed and exit.
 386
 387-p::
 388--paginate::
 389        Pipe all output into 'less' (or if set, $PAGER) if standard
 390        output is a terminal.  This overrides the `pager.<cmd>`
 391        configuration options (see the "Configuration Mechanism" section
 392        below).
 393
 394--no-pager::
 395        Do not pipe git output into a pager.
 396
 397--git-dir=<path>::
 398        Set the path to the repository. This can also be controlled by
 399        setting the GIT_DIR environment variable. It can be an absolute
 400        path or relative path to current working directory.
 401
 402--work-tree=<path>::
 403        Set the path to the working tree. It can be an absolute path
 404        or a path relative to the current working directory.
 405        This can also be controlled by setting the GIT_WORK_TREE
 406        environment variable and the core.worktree configuration
 407        variable (see core.worktree in linkgit:git-config[1] for a
 408        more detailed discussion).
 409
 410--namespace=<path>::
 411        Set the git namespace.  See linkgit:gitnamespaces[7] for more
 412        details.  Equivalent to setting the `GIT_NAMESPACE` environment
 413        variable.
 414
 415--bare::
 416        Treat the repository as a bare repository.  If GIT_DIR
 417        environment is not set, it is set to the current working
 418        directory.
 419
 420--no-replace-objects::
 421        Do not use replacement refs to replace git objects. See
 422        linkgit:git-replace[1] for more information.
 423
 424
 425GIT COMMANDS
 426------------
 427
 428We divide git into high level ("porcelain") commands and low level
 429("plumbing") commands.
 430
 431High-level commands (porcelain)
 432-------------------------------
 433
 434We separate the porcelain commands into the main commands and some
 435ancillary user utilities.
 436
 437Main porcelain commands
 438~~~~~~~~~~~~~~~~~~~~~~~
 439
 440include::cmds-mainporcelain.txt[]
 441
 442Ancillary Commands
 443~~~~~~~~~~~~~~~~~~
 444Manipulators:
 445
 446include::cmds-ancillarymanipulators.txt[]
 447
 448Interrogators:
 449
 450include::cmds-ancillaryinterrogators.txt[]
 451
 452
 453Interacting with Others
 454~~~~~~~~~~~~~~~~~~~~~~~
 455
 456These commands are to interact with foreign SCM and with other
 457people via patch over e-mail.
 458
 459include::cmds-foreignscminterface.txt[]
 460
 461
 462Low-level commands (plumbing)
 463-----------------------------
 464
 465Although git includes its
 466own porcelain layer, its low-level commands are sufficient to support
 467development of alternative porcelains.  Developers of such porcelains
 468might start by reading about linkgit:git-update-index[1] and
 469linkgit:git-read-tree[1].
 470
 471The interface (input, output, set of options and the semantics)
 472to these low-level commands are meant to be a lot more stable
 473than Porcelain level commands, because these commands are
 474primarily for scripted use.  The interface to Porcelain commands
 475on the other hand are subject to change in order to improve the
 476end user experience.
 477
 478The following description divides
 479the low-level commands into commands that manipulate objects (in
 480the repository, index, and working tree), commands that interrogate and
 481compare objects, and commands that move objects and references between
 482repositories.
 483
 484
 485Manipulation commands
 486~~~~~~~~~~~~~~~~~~~~~
 487
 488include::cmds-plumbingmanipulators.txt[]
 489
 490
 491Interrogation commands
 492~~~~~~~~~~~~~~~~~~~~~~
 493
 494include::cmds-plumbinginterrogators.txt[]
 495
 496In general, the interrogate commands do not touch the files in
 497the working tree.
 498
 499
 500Synching repositories
 501~~~~~~~~~~~~~~~~~~~~~
 502
 503include::cmds-synchingrepositories.txt[]
 504
 505The following are helper commands used by the above; end users
 506typically do not use them directly.
 507
 508include::cmds-synchelpers.txt[]
 509
 510
 511Internal helper commands
 512~~~~~~~~~~~~~~~~~~~~~~~~
 513
 514These are internal helper commands used by other commands; end
 515users typically do not use them directly.
 516
 517include::cmds-purehelpers.txt[]
 518
 519
 520Configuration Mechanism
 521-----------------------
 522
 523Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file
 524is used to hold per-repository configuration options.  It is a
 525simple text file modeled after `.ini` format familiar to some
 526people.  Here is an example:
 527
 528------------
 529#
 530# A '#' or ';' character indicates a comment.
 531#
 532
 533; core variables
 534[core]
 535        ; Don't trust file modes
 536        filemode = false
 537
 538; user identity
 539[user]
 540        name = "Junio C Hamano"
 541        email = "junkio@twinsun.com"
 542
 543------------
 544
 545Various commands read from the configuration file and adjust
 546their operation accordingly.  See linkgit:git-config[1] for a
 547list.
 548
 549
 550Identifier Terminology
 551----------------------
 552<object>::
 553        Indicates the object name for any type of object.
 554
 555<blob>::
 556        Indicates a blob object name.
 557
 558<tree>::
 559        Indicates a tree object name.
 560
 561<commit>::
 562        Indicates a commit object name.
 563
 564<tree-ish>::
 565        Indicates a tree, commit or tag object name.  A
 566        command that takes a <tree-ish> argument ultimately wants to
 567        operate on a <tree> object but automatically dereferences
 568        <commit> and <tag> objects that point at a <tree>.
 569
 570<commit-ish>::
 571        Indicates a commit or tag object name.  A
 572        command that takes a <commit-ish> argument ultimately wants to
 573        operate on a <commit> object but automatically dereferences
 574        <tag> objects that point at a <commit>.
 575
 576<type>::
 577        Indicates that an object type is required.
 578        Currently one of: `blob`, `tree`, `commit`, or `tag`.
 579
 580<file>::
 581        Indicates a filename - almost always relative to the
 582        root of the tree structure `GIT_INDEX_FILE` describes.
 583
 584Symbolic Identifiers
 585--------------------
 586Any git command accepting any <object> can also use the following
 587symbolic notation:
 588
 589HEAD::
 590        indicates the head of the current branch.
 591
 592<tag>::
 593        a valid tag 'name'
 594        (i.e. a `refs/tags/<tag>` reference).
 595
 596<head>::
 597        a valid head 'name'
 598        (i.e. a `refs/heads/<head>` reference).
 599
 600For a more complete list of ways to spell object names, see
 601"SPECIFYING REVISIONS" section in linkgit:gitrevisions[7].
 602
 603
 604File/Directory Structure
 605------------------------
 606
 607Please see the linkgit:gitrepository-layout[5] document.
 608
 609Read linkgit:githooks[5] for more details about each hook.
 610
 611Higher level SCMs may provide and manage additional information in the
 612`$GIT_DIR`.
 613
 614
 615Terminology
 616-----------
 617Please see linkgit:gitglossary[7].
 618
 619
 620Environment Variables
 621---------------------
 622Various git commands use the following environment variables:
 623
 624The git Repository
 625~~~~~~~~~~~~~~~~~~
 626These environment variables apply to 'all' core git commands. Nb: it
 627is worth noting that they may be used/overridden by SCMS sitting above
 628git so take care if using Cogito etc.
 629
 630'GIT_INDEX_FILE'::
 631        This environment allows the specification of an alternate
 632        index file. If not specified, the default of `$GIT_DIR/index`
 633        is used.
 634
 635'GIT_OBJECT_DIRECTORY'::
 636        If the object storage directory is specified via this
 637        environment variable then the sha1 directories are created
 638        underneath - otherwise the default `$GIT_DIR/objects`
 639        directory is used.
 640
 641'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
 642        Due to the immutable nature of git objects, old objects can be
 643        archived into shared, read-only directories. This variable
 644        specifies a ":" separated (on Windows ";" separated) list
 645        of git object directories which can be used to search for git
 646        objects. New objects will not be written to these directories.
 647
 648'GIT_DIR'::
 649        If the 'GIT_DIR' environment variable is set then it
 650        specifies a path to use instead of the default `.git`
 651        for the base of the repository.
 652
 653'GIT_WORK_TREE'::
 654        Set the path to the working tree.  The value will not be
 655        used in combination with repositories found automatically in
 656        a .git directory (i.e. $GIT_DIR is not set).
 657        This can also be controlled by the '--work-tree' command line
 658        option and the core.worktree configuration variable.
 659
 660'GIT_NAMESPACE'::
 661        Set the git namespace; see linkgit:gitnamespaces[7] for details.
 662        The '--namespace' command-line option also sets this value.
 663
 664'GIT_CEILING_DIRECTORIES'::
 665        This should be a colon-separated list of absolute paths.
 666        If set, it is a list of directories that git should not chdir
 667        up into while looking for a repository directory.
 668        It will not exclude the current working directory or
 669        a GIT_DIR set on the command line or in the environment.
 670        (Useful for excluding slow-loading network directories.)
 671
 672'GIT_DISCOVERY_ACROSS_FILESYSTEM'::
 673        When run in a directory that does not have ".git" repository
 674        directory, git tries to find such a directory in the parent
 675        directories to find the top of the working tree, but by default it
 676        does not cross filesystem boundaries.  This environment variable
 677        can be set to true to tell git not to stop at filesystem
 678        boundaries.  Like 'GIT_CEILING_DIRECTORIES', this will not affect
 679        an explicit repository directory set via 'GIT_DIR' or on the
 680        command line.
 681
 682git Commits
 683~~~~~~~~~~~
 684'GIT_AUTHOR_NAME'::
 685'GIT_AUTHOR_EMAIL'::
 686'GIT_AUTHOR_DATE'::
 687'GIT_COMMITTER_NAME'::
 688'GIT_COMMITTER_EMAIL'::
 689'GIT_COMMITTER_DATE'::
 690'EMAIL'::
 691        see linkgit:git-commit-tree[1]
 692
 693git Diffs
 694~~~~~~~~~
 695'GIT_DIFF_OPTS'::
 696        Only valid setting is "--unified=??" or "-u??" to set the
 697        number of context lines shown when a unified diff is created.
 698        This takes precedence over any "-U" or "--unified" option
 699        value passed on the git diff command line.
 700
 701'GIT_EXTERNAL_DIFF'::
 702        When the environment variable 'GIT_EXTERNAL_DIFF' is set, the
 703        program named by it is called, instead of the diff invocation
 704        described above.  For a path that is added, removed, or modified,
 705        'GIT_EXTERNAL_DIFF' is called with 7 parameters:
 706
 707        path old-file old-hex old-mode new-file new-hex new-mode
 708+
 709where:
 710
 711        <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the
 712                         contents of <old|new>,
 713        <old|new>-hex:: are the 40-hexdigit SHA1 hashes,
 714        <old|new>-mode:: are the octal representation of the file modes.
 715+
 716The file parameters can point at the user's working file
 717(e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
 718when a new file is added), or a temporary file (e.g. `old-file` in the
 719index).  'GIT_EXTERNAL_DIFF' should not worry about unlinking the
 720temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits.
 721+
 722For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1
 723parameter, <path>.
 724
 725other
 726~~~~~
 727'GIT_MERGE_VERBOSITY'::
 728        A number controlling the amount of output shown by
 729        the recursive merge strategy.  Overrides merge.verbosity.
 730        See linkgit:git-merge[1]
 731
 732'GIT_PAGER'::
 733        This environment variable overrides `$PAGER`. If it is set
 734        to an empty string or to the value "cat", git will not launch
 735        a pager.  See also the `core.pager` option in
 736        linkgit:git-config[1].
 737
 738'GIT_EDITOR'::
 739        This environment variable overrides `$EDITOR` and `$VISUAL`.
 740        It is used by several git commands when, on interactive mode,
 741        an editor is to be launched. See also linkgit:git-var[1]
 742        and the `core.editor` option in linkgit:git-config[1].
 743
 744'GIT_SSH'::
 745        If this environment variable is set then 'git fetch'
 746        and 'git push' will use this command instead
 747        of 'ssh' when they need to connect to a remote system.
 748        The '$GIT_SSH' command will be given exactly two arguments:
 749        the 'username@host' (or just 'host') from the URL and the
 750        shell command to execute on that remote system.
 751+
 752To pass options to the program that you want to list in GIT_SSH
 753you will need to wrap the program and options into a shell script,
 754then set GIT_SSH to refer to the shell script.
 755+
 756Usually it is easier to configure any desired options through your
 757personal `.ssh/config` file.  Please consult your ssh documentation
 758for further details.
 759
 760'GIT_ASKPASS'::
 761        If this environment variable is set, then git commands which need to
 762        acquire passwords or passphrases (e.g. for HTTP or IMAP authentication)
 763        will call this program with a suitable prompt as command line argument
 764        and read the password from its STDOUT. See also the 'core.askpass'
 765        option in linkgit:git-config[1].
 766
 767'GIT_FLUSH'::
 768        If this environment variable is set to "1", then commands such
 769        as 'git blame' (in incremental mode), 'git rev-list', 'git log',
 770        and 'git whatchanged' will force a flush of the output stream
 771        after each commit-oriented record have been flushed.   If this
 772        variable is set to "0", the output of these commands will be done
 773        using completely buffered I/O.   If this environment variable is
 774        not set, git will choose buffered or record-oriented flushing
 775        based on whether stdout appears to be redirected to a file or not.
 776
 777'GIT_TRACE'::
 778        If this variable is set to "1", "2" or "true" (comparison
 779        is case insensitive), git will print `trace:` messages on
 780        stderr telling about alias expansion, built-in command
 781        execution and external command execution.
 782        If this variable is set to an integer value greater than 1
 783        and lower than 10 (strictly) then git will interpret this
 784        value as an open file descriptor and will try to write the
 785        trace messages into this file descriptor.
 786        Alternatively, if this variable is set to an absolute path
 787        (starting with a '/' character), git will interpret this
 788        as a file path and will try to write the trace messages
 789        into it.
 790
 791Discussion[[Discussion]]
 792------------------------
 793
 794More detail on the following is available from the
 795link:user-manual.html#git-concepts[git concepts chapter of the
 796user-manual] and linkgit:gitcore-tutorial[7].
 797
 798A git project normally consists of a working directory with a ".git"
 799subdirectory at the top level.  The .git directory contains, among other
 800things, a compressed object database representing the complete history
 801of the project, an "index" file which links that history to the current
 802contents of the working tree, and named pointers into that history such
 803as tags and branch heads.
 804
 805The object database contains objects of three main types: blobs, which
 806hold file data; trees, which point to blobs and other trees to build up
 807directory hierarchies; and commits, which each reference a single tree
 808and some number of parent commits.
 809
 810The commit, equivalent to what other systems call a "changeset" or
 811"version", represents a step in the project's history, and each parent
 812represents an immediately preceding step.  Commits with more than one
 813parent represent merges of independent lines of development.
 814
 815All objects are named by the SHA1 hash of their contents, normally
 816written as a string of 40 hex digits.  Such names are globally unique.
 817The entire history leading up to a commit can be vouched for by signing
 818just that commit.  A fourth object type, the tag, is provided for this
 819purpose.
 820
 821When first created, objects are stored in individual files, but for
 822efficiency may later be compressed together into "pack files".
 823
 824Named pointers called refs mark interesting points in history.  A ref
 825may contain the SHA1 name of an object or the name of another ref.  Refs
 826with names beginning `ref/head/` contain the SHA1 name of the most
 827recent commit (or "head") of a branch under development.  SHA1 names of
 828tags of interest are stored under `ref/tags/`.  A special ref named
 829`HEAD` contains the name of the currently checked-out branch.
 830
 831The index file is initialized with a list of all paths and, for each
 832path, a blob object and a set of attributes.  The blob object represents
 833the contents of the file as of the head of the current branch.  The
 834attributes (last modified time, size, etc.) are taken from the
 835corresponding file in the working tree.  Subsequent changes to the
 836working tree can be found by comparing these attributes.  The index may
 837be updated with new content, and new commits may be created from the
 838content stored in the index.
 839
 840The index is also capable of storing multiple entries (called "stages")
 841for a given pathname.  These stages are used to hold the various
 842unmerged version of a file when a merge is in progress.
 843
 844FURTHER DOCUMENTATION
 845---------------------
 846
 847See the references in the "description" section to get started
 848using git.  The following is probably more detail than necessary
 849for a first-time user.
 850
 851The link:user-manual.html#git-concepts[git concepts chapter of the
 852user-manual] and linkgit:gitcore-tutorial[7] both provide
 853introductions to the underlying git architecture.
 854
 855See linkgit:gitworkflows[7] for an overview of recommended workflows.
 856
 857See also the link:howto-index.html[howto] documents for some useful
 858examples.
 859
 860The internals are documented in the
 861link:technical/api-index.html[GIT API documentation].
 862
 863Users migrating from CVS may also want to
 864read linkgit:gitcvs-migration[7].
 865
 866
 867Authors
 868-------
 869Git was started by Linus Torvalds, and is currently maintained by Junio
 870C Hamano. Numerous contributions have come from the git mailing list
 871<git@vger.kernel.org>. For a more complete list of contributors, see
 872http://git-scm.com/about. If you have a clone of git.git itself, the
 873output of linkgit:git-shortlog[1] and linkgit:git-blame[1] can show you
 874the authors for specific parts of the project.
 875
 876Reporting Bugs
 877--------------
 878
 879Report bugs to the Git mailing list <git@vger.kernel.org> where the
 880development and maintenance is primarily done.  You do not have to be
 881subscribed to the list to send a message there.
 882
 883SEE ALSO
 884--------
 885linkgit:gittutorial[7], linkgit:gittutorial-2[7],
 886link:everyday.html[Everyday Git], linkgit:gitcvs-migration[7],
 887linkgit:gitglossary[7], linkgit:gitcore-tutorial[7],
 888linkgit:gitcli[7], link:user-manual.html[The Git User's Manual],
 889linkgit:gitworkflows[7]
 890
 891GIT
 892---
 893Part of the linkgit:git[1] suite