Documentation / git.txton commit Merge branch 'ne/pack-local-doc' into maint (162b464)
   1git(1)
   2======
   3
   4NAME
   5----
   6git - the stupid content tracker
   7
   8
   9SYNOPSIS
  10--------
  11[verse]
  12'git' [--version] [--exec-path[=GIT_EXEC_PATH]] [--html-path]
  13    [-p|--paginate|--no-pager] [--no-replace-objects]
  14    [--bare] [--git-dir=GIT_DIR] [--work-tree=GIT_WORK_TREE]
  15    [--help] COMMAND [ARGS]
  16
  17DESCRIPTION
  18-----------
  19Git is a fast, scalable, distributed revision control system with an
  20unusually rich command set that provides both high-level operations
  21and full access to internals.
  22
  23See linkgit:gittutorial[7] to get started, then see
  24link:everyday.html[Everyday Git] for a useful minimum set of commands, and
  25"man git-commandname" for documentation of each command.  CVS users may
  26also want to read linkgit:gitcvs-migration[7].  See
  27the link:user-manual.html[Git User's Manual] for a more in-depth
  28introduction.
  29
  30The COMMAND is either a name of a Git command (see below) or an alias
  31as defined in the configuration file (see linkgit:git-config[1]).
  32
  33Formatted and hyperlinked version of the latest git
  34documentation can be viewed at
  35`http://www.kernel.org/pub/software/scm/git/docs/`.
  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:v1.7.0.2/git.html[documentation for release 1.7.0.2]
  47
  48* release notes for
  49  link:RelNotes-1.7.0.2.txt[1.7.0.2],
  50  link:RelNotes-1.7.0.1.txt[1.7.0.1],
  51  link:RelNotes-1.7.0.txt[1.7.0].
  52
  53* link:v1.6.6.2/git.html[documentation for release 1.6.6.2]
  54
  55* release notes for
  56  link:RelNotes-1.6.6.2.txt[1.6.6.2],
  57  link:RelNotes-1.6.6.1.txt[1.6.6.1],
  58  link:RelNotes-1.6.6.txt[1.6.6].
  59
  60* link:v1.6.5.8/git.html[documentation for release 1.6.5.8]
  61
  62* release notes for
  63  link:RelNotes-1.6.5.8.txt[1.6.5.8],
  64  link:RelNotes-1.6.5.7.txt[1.6.5.7],
  65  link:RelNotes-1.6.5.6.txt[1.6.5.6],
  66  link:RelNotes-1.6.5.5.txt[1.6.5.5],
  67  link:RelNotes-1.6.5.4.txt[1.6.5.4],
  68  link:RelNotes-1.6.5.3.txt[1.6.5.3],
  69  link:RelNotes-1.6.5.2.txt[1.6.5.2],
  70  link:RelNotes-1.6.5.1.txt[1.6.5.1],
  71  link:RelNotes-1.6.5.txt[1.6.5].
  72
  73* link:v1.6.4.4/git.html[documentation for release 1.6.4.4]
  74
  75* release notes for
  76  link:RelNotes-1.6.4.4.txt[1.6.4.4],
  77  link:RelNotes-1.6.4.3.txt[1.6.4.3],
  78  link:RelNotes-1.6.4.2.txt[1.6.4.2],
  79  link:RelNotes-1.6.4.1.txt[1.6.4.1],
  80  link:RelNotes-1.6.4.txt[1.6.4].
  81
  82* link:v1.6.3.4/git.html[documentation for release 1.6.3.4]
  83
  84* release notes for
  85  link:RelNotes-1.6.3.4.txt[1.6.3.4],
  86  link:RelNotes-1.6.3.3.txt[1.6.3.3],
  87  link:RelNotes-1.6.3.2.txt[1.6.3.2],
  88  link:RelNotes-1.6.3.1.txt[1.6.3.1],
  89  link:RelNotes-1.6.3.txt[1.6.3].
  90
  91* release notes for
  92  link:RelNotes-1.6.2.5.txt[1.6.2.5],
  93  link:RelNotes-1.6.2.4.txt[1.6.2.4],
  94  link:RelNotes-1.6.2.3.txt[1.6.2.3],
  95  link:RelNotes-1.6.2.2.txt[1.6.2.2],
  96  link:RelNotes-1.6.2.1.txt[1.6.2.1],
  97  link:RelNotes-1.6.2.txt[1.6.2].
  98
  99* link:v1.6.1.3/git.html[documentation for release 1.6.1.3]
 100
 101* release notes for
 102  link:RelNotes-1.6.1.3.txt[1.6.1.3],
 103  link:RelNotes-1.6.1.2.txt[1.6.1.2],
 104  link:RelNotes-1.6.1.1.txt[1.6.1.1],
 105  link:RelNotes-1.6.1.txt[1.6.1].
 106
 107* link:v1.6.0.6/git.html[documentation for release 1.6.0.6]
 108
 109* release notes for
 110  link:RelNotes-1.6.0.6.txt[1.6.0.6],
 111  link:RelNotes-1.6.0.5.txt[1.6.0.5],
 112  link:RelNotes-1.6.0.4.txt[1.6.0.4],
 113  link:RelNotes-1.6.0.3.txt[1.6.0.3],
 114  link:RelNotes-1.6.0.2.txt[1.6.0.2],
 115  link:RelNotes-1.6.0.1.txt[1.6.0.1],
 116  link:RelNotes-1.6.0.txt[1.6.0].
 117
 118* link:v1.5.6.6/git.html[documentation for release 1.5.6.6]
 119
 120* release notes for
 121  link:RelNotes-1.5.6.6.txt[1.5.6.6],
 122  link:RelNotes-1.5.6.5.txt[1.5.6.5],
 123  link:RelNotes-1.5.6.4.txt[1.5.6.4],
 124  link:RelNotes-1.5.6.3.txt[1.5.6.3],
 125  link:RelNotes-1.5.6.2.txt[1.5.6.2],
 126  link:RelNotes-1.5.6.1.txt[1.5.6.1],
 127  link:RelNotes-1.5.6.txt[1.5.6].
 128
 129* link:v1.5.5.6/git.html[documentation for release 1.5.5.6]
 130
 131* release notes for
 132  link:RelNotes-1.5.5.6.txt[1.5.5.6],
 133  link:RelNotes-1.5.5.5.txt[1.5.5.5],
 134  link:RelNotes-1.5.5.4.txt[1.5.5.4],
 135  link:RelNotes-1.5.5.3.txt[1.5.5.3],
 136  link:RelNotes-1.5.5.2.txt[1.5.5.2],
 137  link:RelNotes-1.5.5.1.txt[1.5.5.1],
 138  link:RelNotes-1.5.5.txt[1.5.5].
 139
 140* link:v1.5.4.7/git.html[documentation for release 1.5.4.7]
 141
 142* release notes for
 143  link:RelNotes-1.5.4.7.txt[1.5.4.7],
 144  link:RelNotes-1.5.4.6.txt[1.5.4.6],
 145  link:RelNotes-1.5.4.5.txt[1.5.4.5],
 146  link:RelNotes-1.5.4.4.txt[1.5.4.4],
 147  link:RelNotes-1.5.4.3.txt[1.5.4.3],
 148  link:RelNotes-1.5.4.2.txt[1.5.4.2],
 149  link:RelNotes-1.5.4.1.txt[1.5.4.1],
 150  link:RelNotes-1.5.4.txt[1.5.4].
 151
 152* link:v1.5.3.8/git.html[documentation for release 1.5.3.8]
 153
 154* release notes for
 155  link:RelNotes-1.5.3.8.txt[1.5.3.8],
 156  link:RelNotes-1.5.3.7.txt[1.5.3.7],
 157  link:RelNotes-1.5.3.6.txt[1.5.3.6],
 158  link:RelNotes-1.5.3.5.txt[1.5.3.5],
 159  link:RelNotes-1.5.3.4.txt[1.5.3.4],
 160  link:RelNotes-1.5.3.3.txt[1.5.3.3],
 161  link:RelNotes-1.5.3.2.txt[1.5.3.2],
 162  link:RelNotes-1.5.3.1.txt[1.5.3.1],
 163  link:RelNotes-1.5.3.txt[1.5.3].
 164
 165* link:v1.5.2.5/git.html[documentation for release 1.5.2.5]
 166
 167* release notes for
 168  link:RelNotes-1.5.2.5.txt[1.5.2.5],
 169  link:RelNotes-1.5.2.4.txt[1.5.2.4],
 170  link:RelNotes-1.5.2.3.txt[1.5.2.3],
 171  link:RelNotes-1.5.2.2.txt[1.5.2.2],
 172  link:RelNotes-1.5.2.1.txt[1.5.2.1],
 173  link:RelNotes-1.5.2.txt[1.5.2].
 174
 175* link:v1.5.1.6/git.html[documentation for release 1.5.1.6]
 176
 177* release notes for
 178  link:RelNotes-1.5.1.6.txt[1.5.1.6],
 179  link:RelNotes-1.5.1.5.txt[1.5.1.5],
 180  link:RelNotes-1.5.1.4.txt[1.5.1.4],
 181  link:RelNotes-1.5.1.3.txt[1.5.1.3],
 182  link:RelNotes-1.5.1.2.txt[1.5.1.2],
 183  link:RelNotes-1.5.1.1.txt[1.5.1.1],
 184  link:RelNotes-1.5.1.txt[1.5.1].
 185
 186* link:v1.5.0.7/git.html[documentation for release 1.5.0.7]
 187
 188* release notes for
 189  link:RelNotes-1.5.0.7.txt[1.5.0.7],
 190  link:RelNotes-1.5.0.6.txt[1.5.0.6],
 191  link:RelNotes-1.5.0.5.txt[1.5.0.5],
 192  link:RelNotes-1.5.0.3.txt[1.5.0.3],
 193  link:RelNotes-1.5.0.2.txt[1.5.0.2],
 194  link:RelNotes-1.5.0.1.txt[1.5.0.1],
 195  link:RelNotes-1.5.0.txt[1.5.0].
 196
 197* documentation for release link:v1.4.4.4/git.html[1.4.4.4],
 198  link:v1.3.3/git.html[1.3.3],
 199  link:v1.2.6/git.html[1.2.6],
 200  link:v1.0.13/git.html[1.0.13].
 201
 202============
 203
 204endif::stalenotes[]
 205
 206OPTIONS
 207-------
 208--version::
 209        Prints the git suite version that the 'git' program came from.
 210
 211--help::
 212        Prints the synopsis and a list of the most commonly used
 213        commands. If the option '--all' or '-a' is given then all
 214        available commands are printed. If a git command is named this
 215        option will bring up the manual page for that command.
 216+
 217Other options are available to control how the manual page is
 218displayed. See linkgit:git-help[1] for more information,
 219because `git --help ...` is converted internally into `git
 220help ...`.
 221
 222--exec-path::
 223        Path to wherever your core git programs are installed.
 224        This can also be controlled by setting the GIT_EXEC_PATH
 225        environment variable. If no path is given, 'git' will print
 226        the current setting and then exit.
 227
 228--html-path::
 229        Print the path to wherever your git HTML documentation is installed
 230        and exit.
 231
 232-p::
 233--paginate::
 234        Pipe all output into 'less' (or if set, $PAGER) if standard
 235        output is a terminal.  This overrides the `pager.<cmd>`
 236        configuration options (see the "Configuration Mechanism" section
 237        below).
 238
 239--no-pager::
 240        Do not pipe git output into a pager.
 241
 242--git-dir=<path>::
 243        Set the path to the repository. This can also be controlled by
 244        setting the GIT_DIR environment variable. It can be an absolute
 245        path or relative path to current working directory.
 246
 247--work-tree=<path>::
 248        Set the path to the working tree.  The value will not be
 249        used in combination with repositories found automatically in
 250        a .git directory (i.e. $GIT_DIR is not set).
 251        This can also be controlled by setting the GIT_WORK_TREE
 252        environment variable and the core.worktree configuration
 253        variable. It can be an absolute path or relative path to
 254        the directory specified by --git-dir or GIT_DIR.
 255        Note: If --git-dir or GIT_DIR are specified but none of
 256        --work-tree, GIT_WORK_TREE and core.worktree is specified,
 257        the current working directory is regarded as the top directory
 258        of your working tree.
 259
 260--bare::
 261        Treat the repository as a bare repository.  If GIT_DIR
 262        environment is not set, it is set to the current working
 263        directory.
 264
 265--no-replace-objects::
 266        Do not use replacement refs to replace git objects. See
 267        linkgit:git-replace[1] for more information.
 268
 269
 270FURTHER DOCUMENTATION
 271---------------------
 272
 273See the references above to get started using git.  The following is
 274probably more detail than necessary for a first-time user.
 275
 276The link:user-manual.html#git-concepts[git concepts chapter of the
 277user-manual] and linkgit:gitcore-tutorial[7] both provide
 278introductions to the underlying git architecture.
 279
 280See linkgit:gitworkflows[7] for an overview of recommended workflows.
 281
 282See also the link:howto-index.html[howto] documents for some useful
 283examples.
 284
 285The internals are documented in the
 286link:technical/api-index.html[GIT API documentation].
 287
 288GIT COMMANDS
 289------------
 290
 291We divide git into high level ("porcelain") commands and low level
 292("plumbing") commands.
 293
 294High-level commands (porcelain)
 295-------------------------------
 296
 297We separate the porcelain commands into the main commands and some
 298ancillary user utilities.
 299
 300Main porcelain commands
 301~~~~~~~~~~~~~~~~~~~~~~~
 302
 303include::cmds-mainporcelain.txt[]
 304
 305Ancillary Commands
 306~~~~~~~~~~~~~~~~~~
 307Manipulators:
 308
 309include::cmds-ancillarymanipulators.txt[]
 310
 311Interrogators:
 312
 313include::cmds-ancillaryinterrogators.txt[]
 314
 315
 316Interacting with Others
 317~~~~~~~~~~~~~~~~~~~~~~~
 318
 319These commands are to interact with foreign SCM and with other
 320people via patch over e-mail.
 321
 322include::cmds-foreignscminterface.txt[]
 323
 324
 325Low-level commands (plumbing)
 326-----------------------------
 327
 328Although git includes its
 329own porcelain layer, its low-level commands are sufficient to support
 330development of alternative porcelains.  Developers of such porcelains
 331might start by reading about linkgit:git-update-index[1] and
 332linkgit:git-read-tree[1].
 333
 334The interface (input, output, set of options and the semantics)
 335to these low-level commands are meant to be a lot more stable
 336than Porcelain level commands, because these commands are
 337primarily for scripted use.  The interface to Porcelain commands
 338on the other hand are subject to change in order to improve the
 339end user experience.
 340
 341The following description divides
 342the low-level commands into commands that manipulate objects (in
 343the repository, index, and working tree), commands that interrogate and
 344compare objects, and commands that move objects and references between
 345repositories.
 346
 347
 348Manipulation commands
 349~~~~~~~~~~~~~~~~~~~~~
 350
 351include::cmds-plumbingmanipulators.txt[]
 352
 353
 354Interrogation commands
 355~~~~~~~~~~~~~~~~~~~~~~
 356
 357include::cmds-plumbinginterrogators.txt[]
 358
 359In general, the interrogate commands do not touch the files in
 360the working tree.
 361
 362
 363Synching repositories
 364~~~~~~~~~~~~~~~~~~~~~
 365
 366include::cmds-synchingrepositories.txt[]
 367
 368The following are helper commands used by the above; end users
 369typically do not use them directly.
 370
 371include::cmds-synchelpers.txt[]
 372
 373
 374Internal helper commands
 375~~~~~~~~~~~~~~~~~~~~~~~~
 376
 377These are internal helper commands used by other commands; end
 378users typically do not use them directly.
 379
 380include::cmds-purehelpers.txt[]
 381
 382
 383Configuration Mechanism
 384-----------------------
 385
 386Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file
 387is used to hold per-repository configuration options.  It is a
 388simple text file modeled after `.ini` format familiar to some
 389people.  Here is an example:
 390
 391------------
 392#
 393# A '#' or ';' character indicates a comment.
 394#
 395
 396; core variables
 397[core]
 398        ; Don't trust file modes
 399        filemode = false
 400
 401; user identity
 402[user]
 403        name = "Junio C Hamano"
 404        email = "junkio@twinsun.com"
 405
 406------------
 407
 408Various commands read from the configuration file and adjust
 409their operation accordingly.  See linkgit:git-config[1] for a
 410list.
 411
 412
 413Identifier Terminology
 414----------------------
 415<object>::
 416        Indicates the object name for any type of object.
 417
 418<blob>::
 419        Indicates a blob object name.
 420
 421<tree>::
 422        Indicates a tree object name.
 423
 424<commit>::
 425        Indicates a commit object name.
 426
 427<tree-ish>::
 428        Indicates a tree, commit or tag object name.  A
 429        command that takes a <tree-ish> argument ultimately wants to
 430        operate on a <tree> object but automatically dereferences
 431        <commit> and <tag> objects that point at a <tree>.
 432
 433<commit-ish>::
 434        Indicates a commit or tag object name.  A
 435        command that takes a <commit-ish> argument ultimately wants to
 436        operate on a <commit> object but automatically dereferences
 437        <tag> objects that point at a <commit>.
 438
 439<type>::
 440        Indicates that an object type is required.
 441        Currently one of: `blob`, `tree`, `commit`, or `tag`.
 442
 443<file>::
 444        Indicates a filename - almost always relative to the
 445        root of the tree structure `GIT_INDEX_FILE` describes.
 446
 447Symbolic Identifiers
 448--------------------
 449Any git command accepting any <object> can also use the following
 450symbolic notation:
 451
 452HEAD::
 453        indicates the head of the current branch (i.e. the
 454        contents of `$GIT_DIR/HEAD`).
 455
 456<tag>::
 457        a valid tag 'name'
 458        (i.e. the contents of `$GIT_DIR/refs/tags/<tag>`).
 459
 460<head>::
 461        a valid head 'name'
 462        (i.e. the contents of `$GIT_DIR/refs/heads/<head>`).
 463
 464For a more complete list of ways to spell object names, see
 465"SPECIFYING REVISIONS" section in linkgit:git-rev-parse[1].
 466
 467
 468File/Directory Structure
 469------------------------
 470
 471Please see the linkgit:gitrepository-layout[5] document.
 472
 473Read linkgit:githooks[5] for more details about each hook.
 474
 475Higher level SCMs may provide and manage additional information in the
 476`$GIT_DIR`.
 477
 478
 479Terminology
 480-----------
 481Please see linkgit:gitglossary[7].
 482
 483
 484Environment Variables
 485---------------------
 486Various git commands use the following environment variables:
 487
 488The git Repository
 489~~~~~~~~~~~~~~~~~~
 490These environment variables apply to 'all' core git commands. Nb: it
 491is worth noting that they may be used/overridden by SCMS sitting above
 492git so take care if using Cogito etc.
 493
 494'GIT_INDEX_FILE'::
 495        This environment allows the specification of an alternate
 496        index file. If not specified, the default of `$GIT_DIR/index`
 497        is used.
 498
 499'GIT_OBJECT_DIRECTORY'::
 500        If the object storage directory is specified via this
 501        environment variable then the sha1 directories are created
 502        underneath - otherwise the default `$GIT_DIR/objects`
 503        directory is used.
 504
 505'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
 506        Due to the immutable nature of git objects, old objects can be
 507        archived into shared, read-only directories. This variable
 508        specifies a ":" separated (on Windows ";" separated) list
 509        of git object directories which can be used to search for git
 510        objects. New objects will not be written to these directories.
 511
 512'GIT_DIR'::
 513        If the 'GIT_DIR' environment variable is set then it
 514        specifies a path to use instead of the default `.git`
 515        for the base of the repository.
 516
 517'GIT_WORK_TREE'::
 518        Set the path to the working tree.  The value will not be
 519        used in combination with repositories found automatically in
 520        a .git directory (i.e. $GIT_DIR is not set).
 521        This can also be controlled by the '--work-tree' command line
 522        option and the core.worktree configuration variable.
 523
 524'GIT_CEILING_DIRECTORIES'::
 525        This should be a colon-separated list of absolute paths.
 526        If set, it is a list of directories that git should not chdir
 527        up into while looking for a repository directory.
 528        It will not exclude the current working directory or
 529        a GIT_DIR set on the command line or in the environment.
 530        (Useful for excluding slow-loading network directories.)
 531
 532git Commits
 533~~~~~~~~~~~
 534'GIT_AUTHOR_NAME'::
 535'GIT_AUTHOR_EMAIL'::
 536'GIT_AUTHOR_DATE'::
 537'GIT_COMMITTER_NAME'::
 538'GIT_COMMITTER_EMAIL'::
 539'GIT_COMMITTER_DATE'::
 540'EMAIL'::
 541        see linkgit:git-commit-tree[1]
 542
 543git Diffs
 544~~~~~~~~~
 545'GIT_DIFF_OPTS'::
 546        Only valid setting is "--unified=??" or "-u??" to set the
 547        number of context lines shown when a unified diff is created.
 548        This takes precedence over any "-U" or "--unified" option
 549        value passed on the git diff command line.
 550
 551'GIT_EXTERNAL_DIFF'::
 552        When the environment variable 'GIT_EXTERNAL_DIFF' is set, the
 553        program named by it is called, instead of the diff invocation
 554        described above.  For a path that is added, removed, or modified,
 555        'GIT_EXTERNAL_DIFF' is called with 7 parameters:
 556
 557        path old-file old-hex old-mode new-file new-hex new-mode
 558+
 559where:
 560
 561        <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the
 562                         contents of <old|new>,
 563        <old|new>-hex:: are the 40-hexdigit SHA1 hashes,
 564        <old|new>-mode:: are the octal representation of the file modes.
 565
 566+
 567The file parameters can point at the user's working file
 568(e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
 569when a new file is added), or a temporary file (e.g. `old-file` in the
 570index).  'GIT_EXTERNAL_DIFF' should not worry about unlinking the
 571temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits.
 572+
 573For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1
 574parameter, <path>.
 575
 576other
 577~~~~~
 578'GIT_MERGE_VERBOSITY'::
 579        A number controlling the amount of output shown by
 580        the recursive merge strategy.  Overrides merge.verbosity.
 581        See linkgit:git-merge[1]
 582
 583'GIT_PAGER'::
 584        This environment variable overrides `$PAGER`. If it is set
 585        to an empty string or to the value "cat", git will not launch
 586        a pager.  See also the `core.pager` option in
 587        linkgit:git-config[1].
 588
 589'GIT_SSH'::
 590        If this environment variable is set then 'git fetch'
 591        and 'git push' will use this command instead
 592        of 'ssh' when they need to connect to a remote system.
 593        The '$GIT_SSH' command will be given exactly two arguments:
 594        the 'username@host' (or just 'host') from the URL and the
 595        shell command to execute on that remote system.
 596+
 597To pass options to the program that you want to list in GIT_SSH
 598you will need to wrap the program and options into a shell script,
 599then set GIT_SSH to refer to the shell script.
 600+
 601Usually it is easier to configure any desired options through your
 602personal `.ssh/config` file.  Please consult your ssh documentation
 603for further details.
 604
 605'GIT_FLUSH'::
 606        If this environment variable is set to "1", then commands such
 607        as 'git blame' (in incremental mode), 'git rev-list', 'git log',
 608        and 'git whatchanged' will force a flush of the output stream
 609        after each commit-oriented record have been flushed.   If this
 610        variable is set to "0", the output of these commands will be done
 611        using completely buffered I/O.   If this environment variable is
 612        not set, git will choose buffered or record-oriented flushing
 613        based on whether stdout appears to be redirected to a file or not.
 614
 615'GIT_TRACE'::
 616        If this variable is set to "1", "2" or "true" (comparison
 617        is case insensitive), git will print `trace:` messages on
 618        stderr telling about alias expansion, built-in command
 619        execution and external command execution.
 620        If this variable is set to an integer value greater than 1
 621        and lower than 10 (strictly) then git will interpret this
 622        value as an open file descriptor and will try to write the
 623        trace messages into this file descriptor.
 624        Alternatively, if this variable is set to an absolute path
 625        (starting with a '/' character), git will interpret this
 626        as a file path and will try to write the trace messages
 627        into it.
 628
 629Discussion[[Discussion]]
 630------------------------
 631
 632More detail on the following is available from the
 633link:user-manual.html#git-concepts[git concepts chapter of the
 634user-manual] and linkgit:gitcore-tutorial[7].
 635
 636A git project normally consists of a working directory with a ".git"
 637subdirectory at the top level.  The .git directory contains, among other
 638things, a compressed object database representing the complete history
 639of the project, an "index" file which links that history to the current
 640contents of the working tree, and named pointers into that history such
 641as tags and branch heads.
 642
 643The object database contains objects of three main types: blobs, which
 644hold file data; trees, which point to blobs and other trees to build up
 645directory hierarchies; and commits, which each reference a single tree
 646and some number of parent commits.
 647
 648The commit, equivalent to what other systems call a "changeset" or
 649"version", represents a step in the project's history, and each parent
 650represents an immediately preceding step.  Commits with more than one
 651parent represent merges of independent lines of development.
 652
 653All objects are named by the SHA1 hash of their contents, normally
 654written as a string of 40 hex digits.  Such names are globally unique.
 655The entire history leading up to a commit can be vouched for by signing
 656just that commit.  A fourth object type, the tag, is provided for this
 657purpose.
 658
 659When first created, objects are stored in individual files, but for
 660efficiency may later be compressed together into "pack files".
 661
 662Named pointers called refs mark interesting points in history.  A ref
 663may contain the SHA1 name of an object or the name of another ref.  Refs
 664with names beginning `ref/head/` contain the SHA1 name of the most
 665recent commit (or "head") of a branch under development.  SHA1 names of
 666tags of interest are stored under `ref/tags/`.  A special ref named
 667`HEAD` contains the name of the currently checked-out branch.
 668
 669The index file is initialized with a list of all paths and, for each
 670path, a blob object and a set of attributes.  The blob object represents
 671the contents of the file as of the head of the current branch.  The
 672attributes (last modified time, size, etc.) are taken from the
 673corresponding file in the working tree.  Subsequent changes to the
 674working tree can be found by comparing these attributes.  The index may
 675be updated with new content, and new commits may be created from the
 676content stored in the index.
 677
 678The index is also capable of storing multiple entries (called "stages")
 679for a given pathname.  These stages are used to hold the various
 680unmerged version of a file when a merge is in progress.
 681
 682Authors
 683-------
 684* git's founding father is Linus Torvalds <torvalds@osdl.org>.
 685* The current git nurse is Junio C Hamano <gitster@pobox.com>.
 686* The git potty was written by Andreas Ericsson <ae@op5.se>.
 687* General upbringing is handled by the git-list <git@vger.kernel.org>.
 688
 689Documentation
 690--------------
 691The documentation for git suite was started by David Greaves
 692<david@dgreaves.com>, and later enhanced greatly by the
 693contributors on the git-list <git@vger.kernel.org>.
 694
 695SEE ALSO
 696--------
 697linkgit:gittutorial[7], linkgit:gittutorial-2[7],
 698link:everyday.html[Everyday Git], linkgit:gitcvs-migration[7],
 699linkgit:gitglossary[7], linkgit:gitcore-tutorial[7],
 700linkgit:gitcli[7], link:user-manual.html[The Git User's Manual],
 701linkgit:gitworkflows[7]
 702
 703GIT
 704---
 705Part of the linkgit:git[1] suite