Documentation / git.txton commit Git 1.6.5.9 (ec82874)
   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]
  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:v1.6.5.8/git.html[documentation for release 1.6.5.8]
  47
  48* release notes for
  49  link:RelNotes-1.6.5.8.txt[1.6.5.8],
  50  link:RelNotes-1.6.5.7.txt[1.6.5.7],
  51  link:RelNotes-1.6.5.6.txt[1.6.5.6],
  52  link:RelNotes-1.6.5.5.txt[1.6.5.5],
  53  link:RelNotes-1.6.5.4.txt[1.6.5.4],
  54  link:RelNotes-1.6.5.3.txt[1.6.5.3],
  55  link:RelNotes-1.6.5.2.txt[1.6.5.2],
  56  link:RelNotes-1.6.5.1.txt[1.6.5.1],
  57  link:RelNotes-1.6.5.txt[1.6.5].
  58
  59* link:v1.6.4.4/git.html[documentation for release 1.6.4.4]
  60
  61* release notes for
  62  link:RelNotes-1.6.4.4.txt[1.6.4.4],
  63  link:RelNotes-1.6.4.3.txt[1.6.4.3],
  64  link:RelNotes-1.6.4.2.txt[1.6.4.2],
  65  link:RelNotes-1.6.4.1.txt[1.6.4.1],
  66  link:RelNotes-1.6.4.txt[1.6.4].
  67
  68* link:v1.6.3.4/git.html[documentation for release 1.6.3.4]
  69
  70* release notes for
  71  link:RelNotes-1.6.3.4.txt[1.6.3.4],
  72  link:RelNotes-1.6.3.3.txt[1.6.3.3],
  73  link:RelNotes-1.6.3.2.txt[1.6.3.2],
  74  link:RelNotes-1.6.3.1.txt[1.6.3.1],
  75  link:RelNotes-1.6.3.txt[1.6.3].
  76
  77* release notes for
  78  link:RelNotes-1.6.2.5.txt[1.6.2.5],
  79  link:RelNotes-1.6.2.4.txt[1.6.2.4],
  80  link:RelNotes-1.6.2.3.txt[1.6.2.3],
  81  link:RelNotes-1.6.2.2.txt[1.6.2.2],
  82  link:RelNotes-1.6.2.1.txt[1.6.2.1],
  83  link:RelNotes-1.6.2.txt[1.6.2].
  84
  85* link:v1.6.1.3/git.html[documentation for release 1.6.1.3]
  86
  87* release notes for
  88  link:RelNotes-1.6.1.3.txt[1.6.1.3],
  89  link:RelNotes-1.6.1.2.txt[1.6.1.2],
  90  link:RelNotes-1.6.1.1.txt[1.6.1.1],
  91  link:RelNotes-1.6.1.txt[1.6.1].
  92
  93* link:v1.6.0.6/git.html[documentation for release 1.6.0.6]
  94
  95* release notes for
  96  link:RelNotes-1.6.0.6.txt[1.6.0.6],
  97  link:RelNotes-1.6.0.5.txt[1.6.0.5],
  98  link:RelNotes-1.6.0.4.txt[1.6.0.4],
  99  link:RelNotes-1.6.0.3.txt[1.6.0.3],
 100  link:RelNotes-1.6.0.2.txt[1.6.0.2],
 101  link:RelNotes-1.6.0.1.txt[1.6.0.1],
 102  link:RelNotes-1.6.0.txt[1.6.0].
 103
 104* link:v1.5.6.6/git.html[documentation for release 1.5.6.6]
 105
 106* release notes for
 107  link:RelNotes-1.5.6.6.txt[1.5.6.6],
 108  link:RelNotes-1.5.6.5.txt[1.5.6.5],
 109  link:RelNotes-1.5.6.4.txt[1.5.6.4],
 110  link:RelNotes-1.5.6.3.txt[1.5.6.3],
 111  link:RelNotes-1.5.6.2.txt[1.5.6.2],
 112  link:RelNotes-1.5.6.1.txt[1.5.6.1],
 113  link:RelNotes-1.5.6.txt[1.5.6].
 114
 115* link:v1.5.5.6/git.html[documentation for release 1.5.5.6]
 116
 117* release notes for
 118  link:RelNotes-1.5.5.6.txt[1.5.5.6],
 119  link:RelNotes-1.5.5.5.txt[1.5.5.5],
 120  link:RelNotes-1.5.5.4.txt[1.5.5.4],
 121  link:RelNotes-1.5.5.3.txt[1.5.5.3],
 122  link:RelNotes-1.5.5.2.txt[1.5.5.2],
 123  link:RelNotes-1.5.5.1.txt[1.5.5.1],
 124  link:RelNotes-1.5.5.txt[1.5.5].
 125
 126* link:v1.5.4.7/git.html[documentation for release 1.5.4.7]
 127
 128* release notes for
 129  link:RelNotes-1.5.4.7.txt[1.5.4.7],
 130  link:RelNotes-1.5.4.6.txt[1.5.4.6],
 131  link:RelNotes-1.5.4.5.txt[1.5.4.5],
 132  link:RelNotes-1.5.4.4.txt[1.5.4.4],
 133  link:RelNotes-1.5.4.3.txt[1.5.4.3],
 134  link:RelNotes-1.5.4.2.txt[1.5.4.2],
 135  link:RelNotes-1.5.4.1.txt[1.5.4.1],
 136  link:RelNotes-1.5.4.txt[1.5.4].
 137
 138* link:v1.5.3.8/git.html[documentation for release 1.5.3.8]
 139
 140* release notes for
 141  link:RelNotes-1.5.3.8.txt[1.5.3.8],
 142  link:RelNotes-1.5.3.7.txt[1.5.3.7],
 143  link:RelNotes-1.5.3.6.txt[1.5.3.6],
 144  link:RelNotes-1.5.3.5.txt[1.5.3.5],
 145  link:RelNotes-1.5.3.4.txt[1.5.3.4],
 146  link:RelNotes-1.5.3.3.txt[1.5.3.3],
 147  link:RelNotes-1.5.3.2.txt[1.5.3.2],
 148  link:RelNotes-1.5.3.1.txt[1.5.3.1],
 149  link:RelNotes-1.5.3.txt[1.5.3].
 150
 151* link:v1.5.2.5/git.html[documentation for release 1.5.2.5]
 152
 153* release notes for
 154  link:RelNotes-1.5.2.5.txt[1.5.2.5],
 155  link:RelNotes-1.5.2.4.txt[1.5.2.4],
 156  link:RelNotes-1.5.2.3.txt[1.5.2.3],
 157  link:RelNotes-1.5.2.2.txt[1.5.2.2],
 158  link:RelNotes-1.5.2.1.txt[1.5.2.1],
 159  link:RelNotes-1.5.2.txt[1.5.2].
 160
 161* link:v1.5.1.6/git.html[documentation for release 1.5.1.6]
 162
 163* release notes for
 164  link:RelNotes-1.5.1.6.txt[1.5.1.6],
 165  link:RelNotes-1.5.1.5.txt[1.5.1.5],
 166  link:RelNotes-1.5.1.4.txt[1.5.1.4],
 167  link:RelNotes-1.5.1.3.txt[1.5.1.3],
 168  link:RelNotes-1.5.1.2.txt[1.5.1.2],
 169  link:RelNotes-1.5.1.1.txt[1.5.1.1],
 170  link:RelNotes-1.5.1.txt[1.5.1].
 171
 172* link:v1.5.0.7/git.html[documentation for release 1.5.0.7]
 173
 174* release notes for
 175  link:RelNotes-1.5.0.7.txt[1.5.0.7],
 176  link:RelNotes-1.5.0.6.txt[1.5.0.6],
 177  link:RelNotes-1.5.0.5.txt[1.5.0.5],
 178  link:RelNotes-1.5.0.3.txt[1.5.0.3],
 179  link:RelNotes-1.5.0.2.txt[1.5.0.2],
 180  link:RelNotes-1.5.0.1.txt[1.5.0.1],
 181  link:RelNotes-1.5.0.txt[1.5.0].
 182
 183* documentation for release link:v1.4.4.4/git.html[1.4.4.4],
 184  link:v1.3.3/git.html[1.3.3],
 185  link:v1.2.6/git.html[1.2.6],
 186  link:v1.0.13/git.html[1.0.13].
 187
 188============
 189
 190endif::stalenotes[]
 191
 192OPTIONS
 193-------
 194--version::
 195        Prints the git suite version that the 'git' program came from.
 196
 197--help::
 198        Prints the synopsis and a list of the most commonly used
 199        commands. If the option '--all' or '-a' is given then all
 200        available commands are printed. If a git command is named this
 201        option will bring up the manual page for that command.
 202+
 203Other options are available to control how the manual page is
 204displayed. See linkgit:git-help[1] for more information,
 205because `git --help ...` is converted internally into `git
 206help ...`.
 207
 208--exec-path::
 209        Path to wherever your core git programs are installed.
 210        This can also be controlled by setting the GIT_EXEC_PATH
 211        environment variable. If no path is given, 'git' will print
 212        the current setting and then exit.
 213
 214--html-path::
 215        Print the path to wherever your git HTML documentation is installed
 216        and exit.
 217
 218-p::
 219--paginate::
 220        Pipe all output into 'less' (or if set, $PAGER).
 221
 222--no-pager::
 223        Do not pipe git output into a pager.
 224
 225--git-dir=<path>::
 226        Set the path to the repository. This can also be controlled by
 227        setting the GIT_DIR environment variable. It can be an absolute
 228        path or relative path to current working directory.
 229
 230--work-tree=<path>::
 231        Set the path to the working tree.  The value will not be
 232        used in combination with repositories found automatically in
 233        a .git directory (i.e. $GIT_DIR is not set).
 234        This can also be controlled by setting the GIT_WORK_TREE
 235        environment variable and the core.worktree configuration
 236        variable. It can be an absolute path or relative path to
 237        the directory specified by --git-dir or GIT_DIR.
 238        Note: If --git-dir or GIT_DIR are specified but none of
 239        --work-tree, GIT_WORK_TREE and core.worktree is specified,
 240        the current working directory is regarded as the top directory
 241        of your working tree.
 242
 243--bare::
 244        Treat the repository as a bare repository.  If GIT_DIR
 245        environment is not set, it is set to the current working
 246        directory.
 247
 248
 249FURTHER DOCUMENTATION
 250---------------------
 251
 252See the references above to get started using git.  The following is
 253probably more detail than necessary for a first-time user.
 254
 255The link:user-manual.html#git-concepts[git concepts chapter of the
 256user-manual] and linkgit:gitcore-tutorial[7] both provide
 257introductions to the underlying git architecture.
 258
 259See linkgit:gitworkflows[7] for an overview of recommended workflows.
 260
 261See also the link:howto-index.html[howto] documents for some useful
 262examples.
 263
 264The internals are documented in the
 265link:technical/api-index.html[GIT API documentation].
 266
 267GIT COMMANDS
 268------------
 269
 270We divide git into high level ("porcelain") commands and low level
 271("plumbing") commands.
 272
 273High-level commands (porcelain)
 274-------------------------------
 275
 276We separate the porcelain commands into the main commands and some
 277ancillary user utilities.
 278
 279Main porcelain commands
 280~~~~~~~~~~~~~~~~~~~~~~~
 281
 282include::cmds-mainporcelain.txt[]
 283
 284Ancillary Commands
 285~~~~~~~~~~~~~~~~~~
 286Manipulators:
 287
 288include::cmds-ancillarymanipulators.txt[]
 289
 290Interrogators:
 291
 292include::cmds-ancillaryinterrogators.txt[]
 293
 294
 295Interacting with Others
 296~~~~~~~~~~~~~~~~~~~~~~~
 297
 298These commands are to interact with foreign SCM and with other
 299people via patch over e-mail.
 300
 301include::cmds-foreignscminterface.txt[]
 302
 303
 304Low-level commands (plumbing)
 305-----------------------------
 306
 307Although git includes its
 308own porcelain layer, its low-level commands are sufficient to support
 309development of alternative porcelains.  Developers of such porcelains
 310might start by reading about linkgit:git-update-index[1] and
 311linkgit:git-read-tree[1].
 312
 313The interface (input, output, set of options and the semantics)
 314to these low-level commands are meant to be a lot more stable
 315than Porcelain level commands, because these commands are
 316primarily for scripted use.  The interface to Porcelain commands
 317on the other hand are subject to change in order to improve the
 318end user experience.
 319
 320The following description divides
 321the low-level commands into commands that manipulate objects (in
 322the repository, index, and working tree), commands that interrogate and
 323compare objects, and commands that move objects and references between
 324repositories.
 325
 326
 327Manipulation commands
 328~~~~~~~~~~~~~~~~~~~~~
 329
 330include::cmds-plumbingmanipulators.txt[]
 331
 332
 333Interrogation commands
 334~~~~~~~~~~~~~~~~~~~~~~
 335
 336include::cmds-plumbinginterrogators.txt[]
 337
 338In general, the interrogate commands do not touch the files in
 339the working tree.
 340
 341
 342Synching repositories
 343~~~~~~~~~~~~~~~~~~~~~
 344
 345include::cmds-synchingrepositories.txt[]
 346
 347The following are helper commands used by the above; end users
 348typically do not use them directly.
 349
 350include::cmds-synchelpers.txt[]
 351
 352
 353Internal helper commands
 354~~~~~~~~~~~~~~~~~~~~~~~~
 355
 356These are internal helper commands used by other commands; end
 357users typically do not use them directly.
 358
 359include::cmds-purehelpers.txt[]
 360
 361
 362Configuration Mechanism
 363-----------------------
 364
 365Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file
 366is used to hold per-repository configuration options.  It is a
 367simple text file modeled after `.ini` format familiar to some
 368people.  Here is an example:
 369
 370------------
 371#
 372# A '#' or ';' character indicates a comment.
 373#
 374
 375; core variables
 376[core]
 377        ; Don't trust file modes
 378        filemode = false
 379
 380; user identity
 381[user]
 382        name = "Junio C Hamano"
 383        email = "junkio@twinsun.com"
 384
 385------------
 386
 387Various commands read from the configuration file and adjust
 388their operation accordingly.
 389
 390
 391Identifier Terminology
 392----------------------
 393<object>::
 394        Indicates the object name for any type of object.
 395
 396<blob>::
 397        Indicates a blob object name.
 398
 399<tree>::
 400        Indicates a tree object name.
 401
 402<commit>::
 403        Indicates a commit object name.
 404
 405<tree-ish>::
 406        Indicates a tree, commit or tag object name.  A
 407        command that takes a <tree-ish> argument ultimately wants to
 408        operate on a <tree> object but automatically dereferences
 409        <commit> and <tag> objects that point at a <tree>.
 410
 411<commit-ish>::
 412        Indicates a commit or tag object name.  A
 413        command that takes a <commit-ish> argument ultimately wants to
 414        operate on a <commit> object but automatically dereferences
 415        <tag> objects that point at a <commit>.
 416
 417<type>::
 418        Indicates that an object type is required.
 419        Currently one of: `blob`, `tree`, `commit`, or `tag`.
 420
 421<file>::
 422        Indicates a filename - almost always relative to the
 423        root of the tree structure `GIT_INDEX_FILE` describes.
 424
 425Symbolic Identifiers
 426--------------------
 427Any git command accepting any <object> can also use the following
 428symbolic notation:
 429
 430HEAD::
 431        indicates the head of the current branch (i.e. the
 432        contents of `$GIT_DIR/HEAD`).
 433
 434<tag>::
 435        a valid tag 'name'
 436        (i.e. the contents of `$GIT_DIR/refs/tags/<tag>`).
 437
 438<head>::
 439        a valid head 'name'
 440        (i.e. the contents of `$GIT_DIR/refs/heads/<head>`).
 441
 442For a more complete list of ways to spell object names, see
 443"SPECIFYING REVISIONS" section in linkgit:git-rev-parse[1].
 444
 445
 446File/Directory Structure
 447------------------------
 448
 449Please see the linkgit:gitrepository-layout[5] document.
 450
 451Read linkgit:githooks[5] for more details about each hook.
 452
 453Higher level SCMs may provide and manage additional information in the
 454`$GIT_DIR`.
 455
 456
 457Terminology
 458-----------
 459Please see linkgit:gitglossary[7].
 460
 461
 462Environment Variables
 463---------------------
 464Various git commands use the following environment variables:
 465
 466The git Repository
 467~~~~~~~~~~~~~~~~~~
 468These environment variables apply to 'all' core git commands. Nb: it
 469is worth noting that they may be used/overridden by SCMS sitting above
 470git so take care if using Cogito etc.
 471
 472'GIT_INDEX_FILE'::
 473        This environment allows the specification of an alternate
 474        index file. If not specified, the default of `$GIT_DIR/index`
 475        is used.
 476
 477'GIT_OBJECT_DIRECTORY'::
 478        If the object storage directory is specified via this
 479        environment variable then the sha1 directories are created
 480        underneath - otherwise the default `$GIT_DIR/objects`
 481        directory is used.
 482
 483'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
 484        Due to the immutable nature of git objects, old objects can be
 485        archived into shared, read-only directories. This variable
 486        specifies a ":" separated (on Windows ";" separated) list
 487        of git object directories which can be used to search for git
 488        objects. New objects will not be written to these directories.
 489
 490'GIT_DIR'::
 491        If the 'GIT_DIR' environment variable is set then it
 492        specifies a path to use instead of the default `.git`
 493        for the base of the repository.
 494
 495'GIT_WORK_TREE'::
 496        Set the path to the working tree.  The value will not be
 497        used in combination with repositories found automatically in
 498        a .git directory (i.e. $GIT_DIR is not set).
 499        This can also be controlled by the '--work-tree' command line
 500        option and the core.worktree configuration variable.
 501
 502'GIT_CEILING_DIRECTORIES'::
 503        This should be a colon-separated list of absolute paths.
 504        If set, it is a list of directories that git should not chdir
 505        up into while looking for a repository directory.
 506        It will not exclude the current working directory or
 507        a GIT_DIR set on the command line or in the environment.
 508        (Useful for excluding slow-loading network directories.)
 509
 510git Commits
 511~~~~~~~~~~~
 512'GIT_AUTHOR_NAME'::
 513'GIT_AUTHOR_EMAIL'::
 514'GIT_AUTHOR_DATE'::
 515'GIT_COMMITTER_NAME'::
 516'GIT_COMMITTER_EMAIL'::
 517'GIT_COMMITTER_DATE'::
 518'EMAIL'::
 519        see linkgit:git-commit-tree[1]
 520
 521git Diffs
 522~~~~~~~~~
 523'GIT_DIFF_OPTS'::
 524        Only valid setting is "--unified=??" or "-u??" to set the
 525        number of context lines shown when a unified diff is created.
 526        This takes precedence over any "-U" or "--unified" option
 527        value passed on the git diff command line.
 528
 529'GIT_EXTERNAL_DIFF'::
 530        When the environment variable 'GIT_EXTERNAL_DIFF' is set, the
 531        program named by it is called, instead of the diff invocation
 532        described above.  For a path that is added, removed, or modified,
 533        'GIT_EXTERNAL_DIFF' is called with 7 parameters:
 534
 535        path old-file old-hex old-mode new-file new-hex new-mode
 536+
 537where:
 538
 539        <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the
 540                         contents of <old|new>,
 541        <old|new>-hex:: are the 40-hexdigit SHA1 hashes,
 542        <old|new>-mode:: are the octal representation of the file modes.
 543
 544+
 545The file parameters can point at the user's working file
 546(e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
 547when a new file is added), or a temporary file (e.g. `old-file` in the
 548index).  'GIT_EXTERNAL_DIFF' should not worry about unlinking the
 549temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits.
 550+
 551For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1
 552parameter, <path>.
 553
 554other
 555~~~~~
 556'GIT_MERGE_VERBOSITY'::
 557        A number controlling the amount of output shown by
 558        the recursive merge strategy.  Overrides merge.verbosity.
 559        See linkgit:git-merge[1]
 560
 561'GIT_PAGER'::
 562        This environment variable overrides `$PAGER`. If it is set
 563        to an empty string or to the value "cat", git will not launch
 564        a pager.  See also the `core.pager` option in
 565        linkgit:git-config[1].
 566
 567'GIT_SSH'::
 568        If this environment variable is set then 'git-fetch'
 569        and 'git-push' will use this command instead
 570        of 'ssh' when they need to connect to a remote system.
 571        The '$GIT_SSH' command will be given exactly two arguments:
 572        the 'username@host' (or just 'host') from the URL and the
 573        shell command to execute on that remote system.
 574+
 575To pass options to the program that you want to list in GIT_SSH
 576you will need to wrap the program and options into a shell script,
 577then set GIT_SSH to refer to the shell script.
 578+
 579Usually it is easier to configure any desired options through your
 580personal `.ssh/config` file.  Please consult your ssh documentation
 581for further details.
 582
 583'GIT_FLUSH'::
 584        If this environment variable is set to "1", then commands such
 585        as 'git-blame' (in incremental mode), 'git-rev-list', 'git-log',
 586        and 'git-whatchanged' will force a flush of the output stream
 587        after each commit-oriented record have been flushed.   If this
 588        variable is set to "0", the output of these commands will be done
 589        using completely buffered I/O.   If this environment variable is
 590        not set, git will choose buffered or record-oriented flushing
 591        based on whether stdout appears to be redirected to a file or not.
 592
 593'GIT_TRACE'::
 594        If this variable is set to "1", "2" or "true" (comparison
 595        is case insensitive), git will print `trace:` messages on
 596        stderr telling about alias expansion, built-in command
 597        execution and external command execution.
 598        If this variable is set to an integer value greater than 1
 599        and lower than 10 (strictly) then git will interpret this
 600        value as an open file descriptor and will try to write the
 601        trace messages into this file descriptor.
 602        Alternatively, if this variable is set to an absolute path
 603        (starting with a '/' character), git will interpret this
 604        as a file path and will try to write the trace messages
 605        into it.
 606
 607Discussion[[Discussion]]
 608------------------------
 609
 610More detail on the following is available from the
 611link:user-manual.html#git-concepts[git concepts chapter of the
 612user-manual] and linkgit:gitcore-tutorial[7].
 613
 614A git project normally consists of a working directory with a ".git"
 615subdirectory at the top level.  The .git directory contains, among other
 616things, a compressed object database representing the complete history
 617of the project, an "index" file which links that history to the current
 618contents of the working tree, and named pointers into that history such
 619as tags and branch heads.
 620
 621The object database contains objects of three main types: blobs, which
 622hold file data; trees, which point to blobs and other trees to build up
 623directory hierarchies; and commits, which each reference a single tree
 624and some number of parent commits.
 625
 626The commit, equivalent to what other systems call a "changeset" or
 627"version", represents a step in the project's history, and each parent
 628represents an immediately preceding step.  Commits with more than one
 629parent represent merges of independent lines of development.
 630
 631All objects are named by the SHA1 hash of their contents, normally
 632written as a string of 40 hex digits.  Such names are globally unique.
 633The entire history leading up to a commit can be vouched for by signing
 634just that commit.  A fourth object type, the tag, is provided for this
 635purpose.
 636
 637When first created, objects are stored in individual files, but for
 638efficiency may later be compressed together into "pack files".
 639
 640Named pointers called refs mark interesting points in history.  A ref
 641may contain the SHA1 name of an object or the name of another ref.  Refs
 642with names beginning `ref/head/` contain the SHA1 name of the most
 643recent commit (or "head") of a branch under development.  SHA1 names of
 644tags of interest are stored under `ref/tags/`.  A special ref named
 645`HEAD` contains the name of the currently checked-out branch.
 646
 647The index file is initialized with a list of all paths and, for each
 648path, a blob object and a set of attributes.  The blob object represents
 649the contents of the file as of the head of the current branch.  The
 650attributes (last modified time, size, etc.) are taken from the
 651corresponding file in the working tree.  Subsequent changes to the
 652working tree can be found by comparing these attributes.  The index may
 653be updated with new content, and new commits may be created from the
 654content stored in the index.
 655
 656The index is also capable of storing multiple entries (called "stages")
 657for a given pathname.  These stages are used to hold the various
 658unmerged version of a file when a merge is in progress.
 659
 660Authors
 661-------
 662* git's founding father is Linus Torvalds <torvalds@osdl.org>.
 663* The current git nurse is Junio C Hamano <gitster@pobox.com>.
 664* The git potty was written by Andreas Ericsson <ae@op5.se>.
 665* General upbringing is handled by the git-list <git@vger.kernel.org>.
 666
 667Documentation
 668--------------
 669The documentation for git suite was started by David Greaves
 670<david@dgreaves.com>, and later enhanced greatly by the
 671contributors on the git-list <git@vger.kernel.org>.
 672
 673SEE ALSO
 674--------
 675linkgit:gittutorial[7], linkgit:gittutorial-2[7],
 676link:everyday.html[Everyday Git], linkgit:gitcvs-migration[7],
 677linkgit:gitglossary[7], linkgit:gitcore-tutorial[7],
 678linkgit:gitcli[7], link:user-manual.html[The Git User's Manual],
 679linkgit:gitworkflows[7]
 680
 681GIT
 682---
 683Part of the linkgit:git[1] suite