Documentation / git.txton commit Merge branch 'maint-1.6.5' into maint-1.6.6 (eb0bcd0)
   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:v1.6.6.2/git.html[documentation for release 1.6.6.2]
  47
  48* release notes for
  49  link:RelNotes-1.6.6.2.txt[1.6.6.2],
  50  link:RelNotes-1.6.6.1.txt[1.6.6.1],
  51  link:RelNotes-1.6.6.txt[1.6.6].
  52
  53* link:v1.6.5.8/git.html[documentation for release 1.6.5.8]
  54
  55* release notes for
  56  link:RelNotes-1.6.5.8.txt[1.6.5.8],
  57  link:RelNotes-1.6.5.7.txt[1.6.5.7],
  58  link:RelNotes-1.6.5.6.txt[1.6.5.6],
  59  link:RelNotes-1.6.5.5.txt[1.6.5.5],
  60  link:RelNotes-1.6.5.4.txt[1.6.5.4],
  61  link:RelNotes-1.6.5.3.txt[1.6.5.3],
  62  link:RelNotes-1.6.5.2.txt[1.6.5.2],
  63  link:RelNotes-1.6.5.1.txt[1.6.5.1],
  64  link:RelNotes-1.6.5.txt[1.6.5].
  65
  66* link:v1.6.4.4/git.html[documentation for release 1.6.4.4]
  67
  68* release notes for
  69  link:RelNotes-1.6.4.4.txt[1.6.4.4],
  70  link:RelNotes-1.6.4.3.txt[1.6.4.3],
  71  link:RelNotes-1.6.4.2.txt[1.6.4.2],
  72  link:RelNotes-1.6.4.1.txt[1.6.4.1],
  73  link:RelNotes-1.6.4.txt[1.6.4].
  74
  75* link:v1.6.3.4/git.html[documentation for release 1.6.3.4]
  76
  77* release notes for
  78  link:RelNotes-1.6.3.4.txt[1.6.3.4],
  79  link:RelNotes-1.6.3.3.txt[1.6.3.3],
  80  link:RelNotes-1.6.3.2.txt[1.6.3.2],
  81  link:RelNotes-1.6.3.1.txt[1.6.3.1],
  82  link:RelNotes-1.6.3.txt[1.6.3].
  83
  84* release notes for
  85  link:RelNotes-1.6.2.5.txt[1.6.2.5],
  86  link:RelNotes-1.6.2.4.txt[1.6.2.4],
  87  link:RelNotes-1.6.2.3.txt[1.6.2.3],
  88  link:RelNotes-1.6.2.2.txt[1.6.2.2],
  89  link:RelNotes-1.6.2.1.txt[1.6.2.1],
  90  link:RelNotes-1.6.2.txt[1.6.2].
  91
  92* link:v1.6.1.3/git.html[documentation for release 1.6.1.3]
  93
  94* release notes for
  95  link:RelNotes-1.6.1.3.txt[1.6.1.3],
  96  link:RelNotes-1.6.1.2.txt[1.6.1.2],
  97  link:RelNotes-1.6.1.1.txt[1.6.1.1],
  98  link:RelNotes-1.6.1.txt[1.6.1].
  99
 100* link:v1.6.0.6/git.html[documentation for release 1.6.0.6]
 101
 102* release notes for
 103  link:RelNotes-1.6.0.6.txt[1.6.0.6],
 104  link:RelNotes-1.6.0.5.txt[1.6.0.5],
 105  link:RelNotes-1.6.0.4.txt[1.6.0.4],
 106  link:RelNotes-1.6.0.3.txt[1.6.0.3],
 107  link:RelNotes-1.6.0.2.txt[1.6.0.2],
 108  link:RelNotes-1.6.0.1.txt[1.6.0.1],
 109  link:RelNotes-1.6.0.txt[1.6.0].
 110
 111* link:v1.5.6.6/git.html[documentation for release 1.5.6.6]
 112
 113* release notes for
 114  link:RelNotes-1.5.6.6.txt[1.5.6.6],
 115  link:RelNotes-1.5.6.5.txt[1.5.6.5],
 116  link:RelNotes-1.5.6.4.txt[1.5.6.4],
 117  link:RelNotes-1.5.6.3.txt[1.5.6.3],
 118  link:RelNotes-1.5.6.2.txt[1.5.6.2],
 119  link:RelNotes-1.5.6.1.txt[1.5.6.1],
 120  link:RelNotes-1.5.6.txt[1.5.6].
 121
 122* link:v1.5.5.6/git.html[documentation for release 1.5.5.6]
 123
 124* release notes for
 125  link:RelNotes-1.5.5.6.txt[1.5.5.6],
 126  link:RelNotes-1.5.5.5.txt[1.5.5.5],
 127  link:RelNotes-1.5.5.4.txt[1.5.5.4],
 128  link:RelNotes-1.5.5.3.txt[1.5.5.3],
 129  link:RelNotes-1.5.5.2.txt[1.5.5.2],
 130  link:RelNotes-1.5.5.1.txt[1.5.5.1],
 131  link:RelNotes-1.5.5.txt[1.5.5].
 132
 133* link:v1.5.4.7/git.html[documentation for release 1.5.4.7]
 134
 135* release notes for
 136  link:RelNotes-1.5.4.7.txt[1.5.4.7],
 137  link:RelNotes-1.5.4.6.txt[1.5.4.6],
 138  link:RelNotes-1.5.4.5.txt[1.5.4.5],
 139  link:RelNotes-1.5.4.4.txt[1.5.4.4],
 140  link:RelNotes-1.5.4.3.txt[1.5.4.3],
 141  link:RelNotes-1.5.4.2.txt[1.5.4.2],
 142  link:RelNotes-1.5.4.1.txt[1.5.4.1],
 143  link:RelNotes-1.5.4.txt[1.5.4].
 144
 145* link:v1.5.3.8/git.html[documentation for release 1.5.3.8]
 146
 147* release notes for
 148  link:RelNotes-1.5.3.8.txt[1.5.3.8],
 149  link:RelNotes-1.5.3.7.txt[1.5.3.7],
 150  link:RelNotes-1.5.3.6.txt[1.5.3.6],
 151  link:RelNotes-1.5.3.5.txt[1.5.3.5],
 152  link:RelNotes-1.5.3.4.txt[1.5.3.4],
 153  link:RelNotes-1.5.3.3.txt[1.5.3.3],
 154  link:RelNotes-1.5.3.2.txt[1.5.3.2],
 155  link:RelNotes-1.5.3.1.txt[1.5.3.1],
 156  link:RelNotes-1.5.3.txt[1.5.3].
 157
 158* link:v1.5.2.5/git.html[documentation for release 1.5.2.5]
 159
 160* release notes for
 161  link:RelNotes-1.5.2.5.txt[1.5.2.5],
 162  link:RelNotes-1.5.2.4.txt[1.5.2.4],
 163  link:RelNotes-1.5.2.3.txt[1.5.2.3],
 164  link:RelNotes-1.5.2.2.txt[1.5.2.2],
 165  link:RelNotes-1.5.2.1.txt[1.5.2.1],
 166  link:RelNotes-1.5.2.txt[1.5.2].
 167
 168* link:v1.5.1.6/git.html[documentation for release 1.5.1.6]
 169
 170* release notes for
 171  link:RelNotes-1.5.1.6.txt[1.5.1.6],
 172  link:RelNotes-1.5.1.5.txt[1.5.1.5],
 173  link:RelNotes-1.5.1.4.txt[1.5.1.4],
 174  link:RelNotes-1.5.1.3.txt[1.5.1.3],
 175  link:RelNotes-1.5.1.2.txt[1.5.1.2],
 176  link:RelNotes-1.5.1.1.txt[1.5.1.1],
 177  link:RelNotes-1.5.1.txt[1.5.1].
 178
 179* link:v1.5.0.7/git.html[documentation for release 1.5.0.7]
 180
 181* release notes for
 182  link:RelNotes-1.5.0.7.txt[1.5.0.7],
 183  link:RelNotes-1.5.0.6.txt[1.5.0.6],
 184  link:RelNotes-1.5.0.5.txt[1.5.0.5],
 185  link:RelNotes-1.5.0.3.txt[1.5.0.3],
 186  link:RelNotes-1.5.0.2.txt[1.5.0.2],
 187  link:RelNotes-1.5.0.1.txt[1.5.0.1],
 188  link:RelNotes-1.5.0.txt[1.5.0].
 189
 190* documentation for release link:v1.4.4.4/git.html[1.4.4.4],
 191  link:v1.3.3/git.html[1.3.3],
 192  link:v1.2.6/git.html[1.2.6],
 193  link:v1.0.13/git.html[1.0.13].
 194
 195============
 196
 197endif::stalenotes[]
 198
 199OPTIONS
 200-------
 201--version::
 202        Prints the git suite version that the 'git' program came from.
 203
 204--help::
 205        Prints the synopsis and a list of the most commonly used
 206        commands. If the option '--all' or '-a' is given then all
 207        available commands are printed. If a git command is named this
 208        option will bring up the manual page for that command.
 209+
 210Other options are available to control how the manual page is
 211displayed. See linkgit:git-help[1] for more information,
 212because `git --help ...` is converted internally into `git
 213help ...`.
 214
 215--exec-path::
 216        Path to wherever your core git programs are installed.
 217        This can also be controlled by setting the GIT_EXEC_PATH
 218        environment variable. If no path is given, 'git' will print
 219        the current setting and then exit.
 220
 221--html-path::
 222        Print the path to wherever your git HTML documentation is installed
 223        and exit.
 224
 225-p::
 226--paginate::
 227        Pipe all output into 'less' (or if set, $PAGER).
 228
 229--no-pager::
 230        Do not pipe git output into a pager.
 231
 232--git-dir=<path>::
 233        Set the path to the repository. This can also be controlled by
 234        setting the GIT_DIR environment variable. It can be an absolute
 235        path or relative path to current working directory.
 236
 237--work-tree=<path>::
 238        Set the path to the working tree.  The value will not be
 239        used in combination with repositories found automatically in
 240        a .git directory (i.e. $GIT_DIR is not set).
 241        This can also be controlled by setting the GIT_WORK_TREE
 242        environment variable and the core.worktree configuration
 243        variable. It can be an absolute path or relative path to
 244        the directory specified by --git-dir or GIT_DIR.
 245        Note: If --git-dir or GIT_DIR are specified but none of
 246        --work-tree, GIT_WORK_TREE and core.worktree is specified,
 247        the current working directory is regarded as the top directory
 248        of your working tree.
 249
 250--bare::
 251        Treat the repository as a bare repository.  If GIT_DIR
 252        environment is not set, it is set to the current working
 253        directory.
 254
 255--no-replace-objects::
 256        Do not use replacement refs to replace git objects. See
 257        linkgit:git-replace[1] for more information.
 258
 259
 260FURTHER DOCUMENTATION
 261---------------------
 262
 263See the references above to get started using git.  The following is
 264probably more detail than necessary for a first-time user.
 265
 266The link:user-manual.html#git-concepts[git concepts chapter of the
 267user-manual] and linkgit:gitcore-tutorial[7] both provide
 268introductions to the underlying git architecture.
 269
 270See linkgit:gitworkflows[7] for an overview of recommended workflows.
 271
 272See also the link:howto-index.html[howto] documents for some useful
 273examples.
 274
 275The internals are documented in the
 276link:technical/api-index.html[GIT API documentation].
 277
 278GIT COMMANDS
 279------------
 280
 281We divide git into high level ("porcelain") commands and low level
 282("plumbing") commands.
 283
 284High-level commands (porcelain)
 285-------------------------------
 286
 287We separate the porcelain commands into the main commands and some
 288ancillary user utilities.
 289
 290Main porcelain commands
 291~~~~~~~~~~~~~~~~~~~~~~~
 292
 293include::cmds-mainporcelain.txt[]
 294
 295Ancillary Commands
 296~~~~~~~~~~~~~~~~~~
 297Manipulators:
 298
 299include::cmds-ancillarymanipulators.txt[]
 300
 301Interrogators:
 302
 303include::cmds-ancillaryinterrogators.txt[]
 304
 305
 306Interacting with Others
 307~~~~~~~~~~~~~~~~~~~~~~~
 308
 309These commands are to interact with foreign SCM and with other
 310people via patch over e-mail.
 311
 312include::cmds-foreignscminterface.txt[]
 313
 314
 315Low-level commands (plumbing)
 316-----------------------------
 317
 318Although git includes its
 319own porcelain layer, its low-level commands are sufficient to support
 320development of alternative porcelains.  Developers of such porcelains
 321might start by reading about linkgit:git-update-index[1] and
 322linkgit:git-read-tree[1].
 323
 324The interface (input, output, set of options and the semantics)
 325to these low-level commands are meant to be a lot more stable
 326than Porcelain level commands, because these commands are
 327primarily for scripted use.  The interface to Porcelain commands
 328on the other hand are subject to change in order to improve the
 329end user experience.
 330
 331The following description divides
 332the low-level commands into commands that manipulate objects (in
 333the repository, index, and working tree), commands that interrogate and
 334compare objects, and commands that move objects and references between
 335repositories.
 336
 337
 338Manipulation commands
 339~~~~~~~~~~~~~~~~~~~~~
 340
 341include::cmds-plumbingmanipulators.txt[]
 342
 343
 344Interrogation commands
 345~~~~~~~~~~~~~~~~~~~~~~
 346
 347include::cmds-plumbinginterrogators.txt[]
 348
 349In general, the interrogate commands do not touch the files in
 350the working tree.
 351
 352
 353Synching repositories
 354~~~~~~~~~~~~~~~~~~~~~
 355
 356include::cmds-synchingrepositories.txt[]
 357
 358The following are helper commands used by the above; end users
 359typically do not use them directly.
 360
 361include::cmds-synchelpers.txt[]
 362
 363
 364Internal helper commands
 365~~~~~~~~~~~~~~~~~~~~~~~~
 366
 367These are internal helper commands used by other commands; end
 368users typically do not use them directly.
 369
 370include::cmds-purehelpers.txt[]
 371
 372
 373Configuration Mechanism
 374-----------------------
 375
 376Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file
 377is used to hold per-repository configuration options.  It is a
 378simple text file modeled after `.ini` format familiar to some
 379people.  Here is an example:
 380
 381------------
 382#
 383# A '#' or ';' character indicates a comment.
 384#
 385
 386; core variables
 387[core]
 388        ; Don't trust file modes
 389        filemode = false
 390
 391; user identity
 392[user]
 393        name = "Junio C Hamano"
 394        email = "junkio@twinsun.com"
 395
 396------------
 397
 398Various commands read from the configuration file and adjust
 399their operation accordingly.
 400
 401
 402Identifier Terminology
 403----------------------
 404<object>::
 405        Indicates the object name for any type of object.
 406
 407<blob>::
 408        Indicates a blob object name.
 409
 410<tree>::
 411        Indicates a tree object name.
 412
 413<commit>::
 414        Indicates a commit object name.
 415
 416<tree-ish>::
 417        Indicates a tree, commit or tag object name.  A
 418        command that takes a <tree-ish> argument ultimately wants to
 419        operate on a <tree> object but automatically dereferences
 420        <commit> and <tag> objects that point at a <tree>.
 421
 422<commit-ish>::
 423        Indicates a commit or tag object name.  A
 424        command that takes a <commit-ish> argument ultimately wants to
 425        operate on a <commit> object but automatically dereferences
 426        <tag> objects that point at a <commit>.
 427
 428<type>::
 429        Indicates that an object type is required.
 430        Currently one of: `blob`, `tree`, `commit`, or `tag`.
 431
 432<file>::
 433        Indicates a filename - almost always relative to the
 434        root of the tree structure `GIT_INDEX_FILE` describes.
 435
 436Symbolic Identifiers
 437--------------------
 438Any git command accepting any <object> can also use the following
 439symbolic notation:
 440
 441HEAD::
 442        indicates the head of the current branch (i.e. the
 443        contents of `$GIT_DIR/HEAD`).
 444
 445<tag>::
 446        a valid tag 'name'
 447        (i.e. the contents of `$GIT_DIR/refs/tags/<tag>`).
 448
 449<head>::
 450        a valid head 'name'
 451        (i.e. the contents of `$GIT_DIR/refs/heads/<head>`).
 452
 453For a more complete list of ways to spell object names, see
 454"SPECIFYING REVISIONS" section in linkgit:git-rev-parse[1].
 455
 456
 457File/Directory Structure
 458------------------------
 459
 460Please see the linkgit:gitrepository-layout[5] document.
 461
 462Read linkgit:githooks[5] for more details about each hook.
 463
 464Higher level SCMs may provide and manage additional information in the
 465`$GIT_DIR`.
 466
 467
 468Terminology
 469-----------
 470Please see linkgit:gitglossary[7].
 471
 472
 473Environment Variables
 474---------------------
 475Various git commands use the following environment variables:
 476
 477The git Repository
 478~~~~~~~~~~~~~~~~~~
 479These environment variables apply to 'all' core git commands. Nb: it
 480is worth noting that they may be used/overridden by SCMS sitting above
 481git so take care if using Cogito etc.
 482
 483'GIT_INDEX_FILE'::
 484        This environment allows the specification of an alternate
 485        index file. If not specified, the default of `$GIT_DIR/index`
 486        is used.
 487
 488'GIT_OBJECT_DIRECTORY'::
 489        If the object storage directory is specified via this
 490        environment variable then the sha1 directories are created
 491        underneath - otherwise the default `$GIT_DIR/objects`
 492        directory is used.
 493
 494'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
 495        Due to the immutable nature of git objects, old objects can be
 496        archived into shared, read-only directories. This variable
 497        specifies a ":" separated (on Windows ";" separated) list
 498        of git object directories which can be used to search for git
 499        objects. New objects will not be written to these directories.
 500
 501'GIT_DIR'::
 502        If the 'GIT_DIR' environment variable is set then it
 503        specifies a path to use instead of the default `.git`
 504        for the base of the repository.
 505
 506'GIT_WORK_TREE'::
 507        Set the path to the working tree.  The value will not be
 508        used in combination with repositories found automatically in
 509        a .git directory (i.e. $GIT_DIR is not set).
 510        This can also be controlled by the '--work-tree' command line
 511        option and the core.worktree configuration variable.
 512
 513'GIT_CEILING_DIRECTORIES'::
 514        This should be a colon-separated list of absolute paths.
 515        If set, it is a list of directories that git should not chdir
 516        up into while looking for a repository directory.
 517        It will not exclude the current working directory or
 518        a GIT_DIR set on the command line or in the environment.
 519        (Useful for excluding slow-loading network directories.)
 520
 521git Commits
 522~~~~~~~~~~~
 523'GIT_AUTHOR_NAME'::
 524'GIT_AUTHOR_EMAIL'::
 525'GIT_AUTHOR_DATE'::
 526'GIT_COMMITTER_NAME'::
 527'GIT_COMMITTER_EMAIL'::
 528'GIT_COMMITTER_DATE'::
 529'EMAIL'::
 530        see linkgit:git-commit-tree[1]
 531
 532git Diffs
 533~~~~~~~~~
 534'GIT_DIFF_OPTS'::
 535        Only valid setting is "--unified=??" or "-u??" to set the
 536        number of context lines shown when a unified diff is created.
 537        This takes precedence over any "-U" or "--unified" option
 538        value passed on the git diff command line.
 539
 540'GIT_EXTERNAL_DIFF'::
 541        When the environment variable 'GIT_EXTERNAL_DIFF' is set, the
 542        program named by it is called, instead of the diff invocation
 543        described above.  For a path that is added, removed, or modified,
 544        'GIT_EXTERNAL_DIFF' is called with 7 parameters:
 545
 546        path old-file old-hex old-mode new-file new-hex new-mode
 547+
 548where:
 549
 550        <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the
 551                         contents of <old|new>,
 552        <old|new>-hex:: are the 40-hexdigit SHA1 hashes,
 553        <old|new>-mode:: are the octal representation of the file modes.
 554
 555+
 556The file parameters can point at the user's working file
 557(e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
 558when a new file is added), or a temporary file (e.g. `old-file` in the
 559index).  'GIT_EXTERNAL_DIFF' should not worry about unlinking the
 560temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits.
 561+
 562For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1
 563parameter, <path>.
 564
 565other
 566~~~~~
 567'GIT_MERGE_VERBOSITY'::
 568        A number controlling the amount of output shown by
 569        the recursive merge strategy.  Overrides merge.verbosity.
 570        See linkgit:git-merge[1]
 571
 572'GIT_PAGER'::
 573        This environment variable overrides `$PAGER`. If it is set
 574        to an empty string or to the value "cat", git will not launch
 575        a pager.  See also the `core.pager` option in
 576        linkgit:git-config[1].
 577
 578'GIT_SSH'::
 579        If this environment variable is set then 'git-fetch'
 580        and 'git-push' will use this command instead
 581        of 'ssh' when they need to connect to a remote system.
 582        The '$GIT_SSH' command will be given exactly two arguments:
 583        the 'username@host' (or just 'host') from the URL and the
 584        shell command to execute on that remote system.
 585+
 586To pass options to the program that you want to list in GIT_SSH
 587you will need to wrap the program and options into a shell script,
 588then set GIT_SSH to refer to the shell script.
 589+
 590Usually it is easier to configure any desired options through your
 591personal `.ssh/config` file.  Please consult your ssh documentation
 592for further details.
 593
 594'GIT_FLUSH'::
 595        If this environment variable is set to "1", then commands such
 596        as 'git-blame' (in incremental mode), 'git-rev-list', 'git-log',
 597        and 'git-whatchanged' will force a flush of the output stream
 598        after each commit-oriented record have been flushed.   If this
 599        variable is set to "0", the output of these commands will be done
 600        using completely buffered I/O.   If this environment variable is
 601        not set, git will choose buffered or record-oriented flushing
 602        based on whether stdout appears to be redirected to a file or not.
 603
 604'GIT_TRACE'::
 605        If this variable is set to "1", "2" or "true" (comparison
 606        is case insensitive), git will print `trace:` messages on
 607        stderr telling about alias expansion, built-in command
 608        execution and external command execution.
 609        If this variable is set to an integer value greater than 1
 610        and lower than 10 (strictly) then git will interpret this
 611        value as an open file descriptor and will try to write the
 612        trace messages into this file descriptor.
 613        Alternatively, if this variable is set to an absolute path
 614        (starting with a '/' character), git will interpret this
 615        as a file path and will try to write the trace messages
 616        into it.
 617
 618Discussion[[Discussion]]
 619------------------------
 620
 621More detail on the following is available from the
 622link:user-manual.html#git-concepts[git concepts chapter of the
 623user-manual] and linkgit:gitcore-tutorial[7].
 624
 625A git project normally consists of a working directory with a ".git"
 626subdirectory at the top level.  The .git directory contains, among other
 627things, a compressed object database representing the complete history
 628of the project, an "index" file which links that history to the current
 629contents of the working tree, and named pointers into that history such
 630as tags and branch heads.
 631
 632The object database contains objects of three main types: blobs, which
 633hold file data; trees, which point to blobs and other trees to build up
 634directory hierarchies; and commits, which each reference a single tree
 635and some number of parent commits.
 636
 637The commit, equivalent to what other systems call a "changeset" or
 638"version", represents a step in the project's history, and each parent
 639represents an immediately preceding step.  Commits with more than one
 640parent represent merges of independent lines of development.
 641
 642All objects are named by the SHA1 hash of their contents, normally
 643written as a string of 40 hex digits.  Such names are globally unique.
 644The entire history leading up to a commit can be vouched for by signing
 645just that commit.  A fourth object type, the tag, is provided for this
 646purpose.
 647
 648When first created, objects are stored in individual files, but for
 649efficiency may later be compressed together into "pack files".
 650
 651Named pointers called refs mark interesting points in history.  A ref
 652may contain the SHA1 name of an object or the name of another ref.  Refs
 653with names beginning `ref/head/` contain the SHA1 name of the most
 654recent commit (or "head") of a branch under development.  SHA1 names of
 655tags of interest are stored under `ref/tags/`.  A special ref named
 656`HEAD` contains the name of the currently checked-out branch.
 657
 658The index file is initialized with a list of all paths and, for each
 659path, a blob object and a set of attributes.  The blob object represents
 660the contents of the file as of the head of the current branch.  The
 661attributes (last modified time, size, etc.) are taken from the
 662corresponding file in the working tree.  Subsequent changes to the
 663working tree can be found by comparing these attributes.  The index may
 664be updated with new content, and new commits may be created from the
 665content stored in the index.
 666
 667The index is also capable of storing multiple entries (called "stages")
 668for a given pathname.  These stages are used to hold the various
 669unmerged version of a file when a merge is in progress.
 670
 671Authors
 672-------
 673* git's founding father is Linus Torvalds <torvalds@osdl.org>.
 674* The current git nurse is Junio C Hamano <gitster@pobox.com>.
 675* The git potty was written by Andreas Ericsson <ae@op5.se>.
 676* General upbringing is handled by the git-list <git@vger.kernel.org>.
 677
 678Documentation
 679--------------
 680The documentation for git suite was started by David Greaves
 681<david@dgreaves.com>, and later enhanced greatly by the
 682contributors on the git-list <git@vger.kernel.org>.
 683
 684SEE ALSO
 685--------
 686linkgit:gittutorial[7], linkgit:gittutorial-2[7],
 687link:everyday.html[Everyday Git], linkgit:gitcvs-migration[7],
 688linkgit:gitglossary[7], linkgit:gitcore-tutorial[7],
 689linkgit:gitcli[7], link:user-manual.html[The Git User's Manual],
 690linkgit:gitworkflows[7]
 691
 692GIT
 693---
 694Part of the linkgit:git[1] suite