Documentation / git.txton commit git svn: Fix launching of pager (190c1cd)
   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/git.html[documentation for release 1.7.0]
  47
  48* release notes for
  49  link:RelNotes-1.7.0.txt[1.7.0].
  50
  51* link:v1.6.6.2/git.html[documentation for release 1.6.6.2]
  52
  53* release notes for
  54  link:RelNotes-1.6.6.2.txt[1.6.6.2],
  55  link:RelNotes-1.6.6.1.txt[1.6.6.1],
  56  link:RelNotes-1.6.6.txt[1.6.6].
  57
  58* link:v1.6.5.8/git.html[documentation for release 1.6.5.8]
  59
  60* release notes for
  61  link:RelNotes-1.6.5.8.txt[1.6.5.8],
  62  link:RelNotes-1.6.5.7.txt[1.6.5.7],
  63  link:RelNotes-1.6.5.6.txt[1.6.5.6],
  64  link:RelNotes-1.6.5.5.txt[1.6.5.5],
  65  link:RelNotes-1.6.5.4.txt[1.6.5.4],
  66  link:RelNotes-1.6.5.3.txt[1.6.5.3],
  67  link:RelNotes-1.6.5.2.txt[1.6.5.2],
  68  link:RelNotes-1.6.5.1.txt[1.6.5.1],
  69  link:RelNotes-1.6.5.txt[1.6.5].
  70
  71* link:v1.6.4.4/git.html[documentation for release 1.6.4.4]
  72
  73* release notes for
  74  link:RelNotes-1.6.4.4.txt[1.6.4.4],
  75  link:RelNotes-1.6.4.3.txt[1.6.4.3],
  76  link:RelNotes-1.6.4.2.txt[1.6.4.2],
  77  link:RelNotes-1.6.4.1.txt[1.6.4.1],
  78  link:RelNotes-1.6.4.txt[1.6.4].
  79
  80* link:v1.6.3.4/git.html[documentation for release 1.6.3.4]
  81
  82* release notes for
  83  link:RelNotes-1.6.3.4.txt[1.6.3.4],
  84  link:RelNotes-1.6.3.3.txt[1.6.3.3],
  85  link:RelNotes-1.6.3.2.txt[1.6.3.2],
  86  link:RelNotes-1.6.3.1.txt[1.6.3.1],
  87  link:RelNotes-1.6.3.txt[1.6.3].
  88
  89* release notes for
  90  link:RelNotes-1.6.2.5.txt[1.6.2.5],
  91  link:RelNotes-1.6.2.4.txt[1.6.2.4],
  92  link:RelNotes-1.6.2.3.txt[1.6.2.3],
  93  link:RelNotes-1.6.2.2.txt[1.6.2.2],
  94  link:RelNotes-1.6.2.1.txt[1.6.2.1],
  95  link:RelNotes-1.6.2.txt[1.6.2].
  96
  97* link:v1.6.1.3/git.html[documentation for release 1.6.1.3]
  98
  99* release notes for
 100  link:RelNotes-1.6.1.3.txt[1.6.1.3],
 101  link:RelNotes-1.6.1.2.txt[1.6.1.2],
 102  link:RelNotes-1.6.1.1.txt[1.6.1.1],
 103  link:RelNotes-1.6.1.txt[1.6.1].
 104
 105* link:v1.6.0.6/git.html[documentation for release 1.6.0.6]
 106
 107* release notes for
 108  link:RelNotes-1.6.0.6.txt[1.6.0.6],
 109  link:RelNotes-1.6.0.5.txt[1.6.0.5],
 110  link:RelNotes-1.6.0.4.txt[1.6.0.4],
 111  link:RelNotes-1.6.0.3.txt[1.6.0.3],
 112  link:RelNotes-1.6.0.2.txt[1.6.0.2],
 113  link:RelNotes-1.6.0.1.txt[1.6.0.1],
 114  link:RelNotes-1.6.0.txt[1.6.0].
 115
 116* link:v1.5.6.6/git.html[documentation for release 1.5.6.6]
 117
 118* release notes for
 119  link:RelNotes-1.5.6.6.txt[1.5.6.6],
 120  link:RelNotes-1.5.6.5.txt[1.5.6.5],
 121  link:RelNotes-1.5.6.4.txt[1.5.6.4],
 122  link:RelNotes-1.5.6.3.txt[1.5.6.3],
 123  link:RelNotes-1.5.6.2.txt[1.5.6.2],
 124  link:RelNotes-1.5.6.1.txt[1.5.6.1],
 125  link:RelNotes-1.5.6.txt[1.5.6].
 126
 127* link:v1.5.5.6/git.html[documentation for release 1.5.5.6]
 128
 129* release notes for
 130  link:RelNotes-1.5.5.6.txt[1.5.5.6],
 131  link:RelNotes-1.5.5.5.txt[1.5.5.5],
 132  link:RelNotes-1.5.5.4.txt[1.5.5.4],
 133  link:RelNotes-1.5.5.3.txt[1.5.5.3],
 134  link:RelNotes-1.5.5.2.txt[1.5.5.2],
 135  link:RelNotes-1.5.5.1.txt[1.5.5.1],
 136  link:RelNotes-1.5.5.txt[1.5.5].
 137
 138* link:v1.5.4.7/git.html[documentation for release 1.5.4.7]
 139
 140* release notes for
 141  link:RelNotes-1.5.4.7.txt[1.5.4.7],
 142  link:RelNotes-1.5.4.6.txt[1.5.4.6],
 143  link:RelNotes-1.5.4.5.txt[1.5.4.5],
 144  link:RelNotes-1.5.4.4.txt[1.5.4.4],
 145  link:RelNotes-1.5.4.3.txt[1.5.4.3],
 146  link:RelNotes-1.5.4.2.txt[1.5.4.2],
 147  link:RelNotes-1.5.4.1.txt[1.5.4.1],
 148  link:RelNotes-1.5.4.txt[1.5.4].
 149
 150* link:v1.5.3.8/git.html[documentation for release 1.5.3.8]
 151
 152* release notes for
 153  link:RelNotes-1.5.3.8.txt[1.5.3.8],
 154  link:RelNotes-1.5.3.7.txt[1.5.3.7],
 155  link:RelNotes-1.5.3.6.txt[1.5.3.6],
 156  link:RelNotes-1.5.3.5.txt[1.5.3.5],
 157  link:RelNotes-1.5.3.4.txt[1.5.3.4],
 158  link:RelNotes-1.5.3.3.txt[1.5.3.3],
 159  link:RelNotes-1.5.3.2.txt[1.5.3.2],
 160  link:RelNotes-1.5.3.1.txt[1.5.3.1],
 161  link:RelNotes-1.5.3.txt[1.5.3].
 162
 163* link:v1.5.2.5/git.html[documentation for release 1.5.2.5]
 164
 165* release notes for
 166  link:RelNotes-1.5.2.5.txt[1.5.2.5],
 167  link:RelNotes-1.5.2.4.txt[1.5.2.4],
 168  link:RelNotes-1.5.2.3.txt[1.5.2.3],
 169  link:RelNotes-1.5.2.2.txt[1.5.2.2],
 170  link:RelNotes-1.5.2.1.txt[1.5.2.1],
 171  link:RelNotes-1.5.2.txt[1.5.2].
 172
 173* link:v1.5.1.6/git.html[documentation for release 1.5.1.6]
 174
 175* release notes for
 176  link:RelNotes-1.5.1.6.txt[1.5.1.6],
 177  link:RelNotes-1.5.1.5.txt[1.5.1.5],
 178  link:RelNotes-1.5.1.4.txt[1.5.1.4],
 179  link:RelNotes-1.5.1.3.txt[1.5.1.3],
 180  link:RelNotes-1.5.1.2.txt[1.5.1.2],
 181  link:RelNotes-1.5.1.1.txt[1.5.1.1],
 182  link:RelNotes-1.5.1.txt[1.5.1].
 183
 184* link:v1.5.0.7/git.html[documentation for release 1.5.0.7]
 185
 186* release notes for
 187  link:RelNotes-1.5.0.7.txt[1.5.0.7],
 188  link:RelNotes-1.5.0.6.txt[1.5.0.6],
 189  link:RelNotes-1.5.0.5.txt[1.5.0.5],
 190  link:RelNotes-1.5.0.3.txt[1.5.0.3],
 191  link:RelNotes-1.5.0.2.txt[1.5.0.2],
 192  link:RelNotes-1.5.0.1.txt[1.5.0.1],
 193  link:RelNotes-1.5.0.txt[1.5.0].
 194
 195* documentation for release link:v1.4.4.4/git.html[1.4.4.4],
 196  link:v1.3.3/git.html[1.3.3],
 197  link:v1.2.6/git.html[1.2.6],
 198  link:v1.0.13/git.html[1.0.13].
 199
 200============
 201
 202endif::stalenotes[]
 203
 204OPTIONS
 205-------
 206--version::
 207        Prints the git suite version that the 'git' program came from.
 208
 209--help::
 210        Prints the synopsis and a list of the most commonly used
 211        commands. If the option '--all' or '-a' is given then all
 212        available commands are printed. If a git command is named this
 213        option will bring up the manual page for that command.
 214+
 215Other options are available to control how the manual page is
 216displayed. See linkgit:git-help[1] for more information,
 217because `git --help ...` is converted internally into `git
 218help ...`.
 219
 220--exec-path::
 221        Path to wherever your core git programs are installed.
 222        This can also be controlled by setting the GIT_EXEC_PATH
 223        environment variable. If no path is given, 'git' will print
 224        the current setting and then exit.
 225
 226--html-path::
 227        Print the path to wherever your git HTML documentation is installed
 228        and exit.
 229
 230-p::
 231--paginate::
 232        Pipe all output into 'less' (or if set, $PAGER) if standard
 233        output is a terminal.  This overrides the `pager.<cmd>`
 234        configuration options (see the "Configuration Mechanism" section
 235        below).
 236
 237--no-pager::
 238        Do not pipe git output into a pager.
 239
 240--git-dir=<path>::
 241        Set the path to the repository. This can also be controlled by
 242        setting the GIT_DIR environment variable. It can be an absolute
 243        path or relative path to current working directory.
 244
 245--work-tree=<path>::
 246        Set the path to the working tree.  The value will not be
 247        used in combination with repositories found automatically in
 248        a .git directory (i.e. $GIT_DIR is not set).
 249        This can also be controlled by setting the GIT_WORK_TREE
 250        environment variable and the core.worktree configuration
 251        variable. It can be an absolute path or relative path to
 252        the directory specified by --git-dir or GIT_DIR.
 253        Note: If --git-dir or GIT_DIR are specified but none of
 254        --work-tree, GIT_WORK_TREE and core.worktree is specified,
 255        the current working directory is regarded as the top directory
 256        of your working tree.
 257
 258--bare::
 259        Treat the repository as a bare repository.  If GIT_DIR
 260        environment is not set, it is set to the current working
 261        directory.
 262
 263--no-replace-objects::
 264        Do not use replacement refs to replace git objects. See
 265        linkgit:git-replace[1] for more information.
 266
 267
 268FURTHER DOCUMENTATION
 269---------------------
 270
 271See the references above to get started using git.  The following is
 272probably more detail than necessary for a first-time user.
 273
 274The link:user-manual.html#git-concepts[git concepts chapter of the
 275user-manual] and linkgit:gitcore-tutorial[7] both provide
 276introductions to the underlying git architecture.
 277
 278See linkgit:gitworkflows[7] for an overview of recommended workflows.
 279
 280See also the link:howto-index.html[howto] documents for some useful
 281examples.
 282
 283The internals are documented in the
 284link:technical/api-index.html[GIT API documentation].
 285
 286GIT COMMANDS
 287------------
 288
 289We divide git into high level ("porcelain") commands and low level
 290("plumbing") commands.
 291
 292High-level commands (porcelain)
 293-------------------------------
 294
 295We separate the porcelain commands into the main commands and some
 296ancillary user utilities.
 297
 298Main porcelain commands
 299~~~~~~~~~~~~~~~~~~~~~~~
 300
 301include::cmds-mainporcelain.txt[]
 302
 303Ancillary Commands
 304~~~~~~~~~~~~~~~~~~
 305Manipulators:
 306
 307include::cmds-ancillarymanipulators.txt[]
 308
 309Interrogators:
 310
 311include::cmds-ancillaryinterrogators.txt[]
 312
 313
 314Interacting with Others
 315~~~~~~~~~~~~~~~~~~~~~~~
 316
 317These commands are to interact with foreign SCM and with other
 318people via patch over e-mail.
 319
 320include::cmds-foreignscminterface.txt[]
 321
 322
 323Low-level commands (plumbing)
 324-----------------------------
 325
 326Although git includes its
 327own porcelain layer, its low-level commands are sufficient to support
 328development of alternative porcelains.  Developers of such porcelains
 329might start by reading about linkgit:git-update-index[1] and
 330linkgit:git-read-tree[1].
 331
 332The interface (input, output, set of options and the semantics)
 333to these low-level commands are meant to be a lot more stable
 334than Porcelain level commands, because these commands are
 335primarily for scripted use.  The interface to Porcelain commands
 336on the other hand are subject to change in order to improve the
 337end user experience.
 338
 339The following description divides
 340the low-level commands into commands that manipulate objects (in
 341the repository, index, and working tree), commands that interrogate and
 342compare objects, and commands that move objects and references between
 343repositories.
 344
 345
 346Manipulation commands
 347~~~~~~~~~~~~~~~~~~~~~
 348
 349include::cmds-plumbingmanipulators.txt[]
 350
 351
 352Interrogation commands
 353~~~~~~~~~~~~~~~~~~~~~~
 354
 355include::cmds-plumbinginterrogators.txt[]
 356
 357In general, the interrogate commands do not touch the files in
 358the working tree.
 359
 360
 361Synching repositories
 362~~~~~~~~~~~~~~~~~~~~~
 363
 364include::cmds-synchingrepositories.txt[]
 365
 366The following are helper commands used by the above; end users
 367typically do not use them directly.
 368
 369include::cmds-synchelpers.txt[]
 370
 371
 372Internal helper commands
 373~~~~~~~~~~~~~~~~~~~~~~~~
 374
 375These are internal helper commands used by other commands; end
 376users typically do not use them directly.
 377
 378include::cmds-purehelpers.txt[]
 379
 380
 381Configuration Mechanism
 382-----------------------
 383
 384Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file
 385is used to hold per-repository configuration options.  It is a
 386simple text file modeled after `.ini` format familiar to some
 387people.  Here is an example:
 388
 389------------
 390#
 391# A '#' or ';' character indicates a comment.
 392#
 393
 394; core variables
 395[core]
 396        ; Don't trust file modes
 397        filemode = false
 398
 399; user identity
 400[user]
 401        name = "Junio C Hamano"
 402        email = "junkio@twinsun.com"
 403
 404------------
 405
 406Various commands read from the configuration file and adjust
 407their operation accordingly.  See linkgit:git-config[1] for a
 408list.
 409
 410
 411Identifier Terminology
 412----------------------
 413<object>::
 414        Indicates the object name for any type of object.
 415
 416<blob>::
 417        Indicates a blob object name.
 418
 419<tree>::
 420        Indicates a tree object name.
 421
 422<commit>::
 423        Indicates a commit object name.
 424
 425<tree-ish>::
 426        Indicates a tree, commit or tag object name.  A
 427        command that takes a <tree-ish> argument ultimately wants to
 428        operate on a <tree> object but automatically dereferences
 429        <commit> and <tag> objects that point at a <tree>.
 430
 431<commit-ish>::
 432        Indicates a commit or tag object name.  A
 433        command that takes a <commit-ish> argument ultimately wants to
 434        operate on a <commit> object but automatically dereferences
 435        <tag> objects that point at a <commit>.
 436
 437<type>::
 438        Indicates that an object type is required.
 439        Currently one of: `blob`, `tree`, `commit`, or `tag`.
 440
 441<file>::
 442        Indicates a filename - almost always relative to the
 443        root of the tree structure `GIT_INDEX_FILE` describes.
 444
 445Symbolic Identifiers
 446--------------------
 447Any git command accepting any <object> can also use the following
 448symbolic notation:
 449
 450HEAD::
 451        indicates the head of the current branch (i.e. the
 452        contents of `$GIT_DIR/HEAD`).
 453
 454<tag>::
 455        a valid tag 'name'
 456        (i.e. the contents of `$GIT_DIR/refs/tags/<tag>`).
 457
 458<head>::
 459        a valid head 'name'
 460        (i.e. the contents of `$GIT_DIR/refs/heads/<head>`).
 461
 462For a more complete list of ways to spell object names, see
 463"SPECIFYING REVISIONS" section in linkgit:git-rev-parse[1].
 464
 465
 466File/Directory Structure
 467------------------------
 468
 469Please see the linkgit:gitrepository-layout[5] document.
 470
 471Read linkgit:githooks[5] for more details about each hook.
 472
 473Higher level SCMs may provide and manage additional information in the
 474`$GIT_DIR`.
 475
 476
 477Terminology
 478-----------
 479Please see linkgit:gitglossary[7].
 480
 481
 482Environment Variables
 483---------------------
 484Various git commands use the following environment variables:
 485
 486The git Repository
 487~~~~~~~~~~~~~~~~~~
 488These environment variables apply to 'all' core git commands. Nb: it
 489is worth noting that they may be used/overridden by SCMS sitting above
 490git so take care if using Cogito etc.
 491
 492'GIT_INDEX_FILE'::
 493        This environment allows the specification of an alternate
 494        index file. If not specified, the default of `$GIT_DIR/index`
 495        is used.
 496
 497'GIT_OBJECT_DIRECTORY'::
 498        If the object storage directory is specified via this
 499        environment variable then the sha1 directories are created
 500        underneath - otherwise the default `$GIT_DIR/objects`
 501        directory is used.
 502
 503'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
 504        Due to the immutable nature of git objects, old objects can be
 505        archived into shared, read-only directories. This variable
 506        specifies a ":" separated (on Windows ";" separated) list
 507        of git object directories which can be used to search for git
 508        objects. New objects will not be written to these directories.
 509
 510'GIT_DIR'::
 511        If the 'GIT_DIR' environment variable is set then it
 512        specifies a path to use instead of the default `.git`
 513        for the base of the repository.
 514
 515'GIT_WORK_TREE'::
 516        Set the path to the working tree.  The value will not be
 517        used in combination with repositories found automatically in
 518        a .git directory (i.e. $GIT_DIR is not set).
 519        This can also be controlled by the '--work-tree' command line
 520        option and the core.worktree configuration variable.
 521
 522'GIT_CEILING_DIRECTORIES'::
 523        This should be a colon-separated list of absolute paths.
 524        If set, it is a list of directories that git should not chdir
 525        up into while looking for a repository directory.
 526        It will not exclude the current working directory or
 527        a GIT_DIR set on the command line or in the environment.
 528        (Useful for excluding slow-loading network directories.)
 529
 530git Commits
 531~~~~~~~~~~~
 532'GIT_AUTHOR_NAME'::
 533'GIT_AUTHOR_EMAIL'::
 534'GIT_AUTHOR_DATE'::
 535'GIT_COMMITTER_NAME'::
 536'GIT_COMMITTER_EMAIL'::
 537'GIT_COMMITTER_DATE'::
 538'EMAIL'::
 539        see linkgit:git-commit-tree[1]
 540
 541git Diffs
 542~~~~~~~~~
 543'GIT_DIFF_OPTS'::
 544        Only valid setting is "--unified=??" or "-u??" to set the
 545        number of context lines shown when a unified diff is created.
 546        This takes precedence over any "-U" or "--unified" option
 547        value passed on the git diff command line.
 548
 549'GIT_EXTERNAL_DIFF'::
 550        When the environment variable 'GIT_EXTERNAL_DIFF' is set, the
 551        program named by it is called, instead of the diff invocation
 552        described above.  For a path that is added, removed, or modified,
 553        'GIT_EXTERNAL_DIFF' is called with 7 parameters:
 554
 555        path old-file old-hex old-mode new-file new-hex new-mode
 556+
 557where:
 558
 559        <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the
 560                         contents of <old|new>,
 561        <old|new>-hex:: are the 40-hexdigit SHA1 hashes,
 562        <old|new>-mode:: are the octal representation of the file modes.
 563
 564+
 565The file parameters can point at the user's working file
 566(e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
 567when a new file is added), or a temporary file (e.g. `old-file` in the
 568index).  'GIT_EXTERNAL_DIFF' should not worry about unlinking the
 569temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits.
 570+
 571For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1
 572parameter, <path>.
 573
 574other
 575~~~~~
 576'GIT_MERGE_VERBOSITY'::
 577        A number controlling the amount of output shown by
 578        the recursive merge strategy.  Overrides merge.verbosity.
 579        See linkgit:git-merge[1]
 580
 581'GIT_PAGER'::
 582        This environment variable overrides `$PAGER`. If it is set
 583        to an empty string or to the value "cat", git will not launch
 584        a pager.  See also the `core.pager` option in
 585        linkgit:git-config[1].
 586
 587'GIT_SSH'::
 588        If this environment variable is set then 'git fetch'
 589        and 'git push' will use this command instead
 590        of 'ssh' when they need to connect to a remote system.
 591        The '$GIT_SSH' command will be given exactly two arguments:
 592        the 'username@host' (or just 'host') from the URL and the
 593        shell command to execute on that remote system.
 594+
 595To pass options to the program that you want to list in GIT_SSH
 596you will need to wrap the program and options into a shell script,
 597then set GIT_SSH to refer to the shell script.
 598+
 599Usually it is easier to configure any desired options through your
 600personal `.ssh/config` file.  Please consult your ssh documentation
 601for further details.
 602
 603'GIT_FLUSH'::
 604        If this environment variable is set to "1", then commands such
 605        as 'git blame' (in incremental mode), 'git rev-list', 'git log',
 606        and 'git whatchanged' will force a flush of the output stream
 607        after each commit-oriented record have been flushed.   If this
 608        variable is set to "0", the output of these commands will be done
 609        using completely buffered I/O.   If this environment variable is
 610        not set, git will choose buffered or record-oriented flushing
 611        based on whether stdout appears to be redirected to a file or not.
 612
 613'GIT_TRACE'::
 614        If this variable is set to "1", "2" or "true" (comparison
 615        is case insensitive), git will print `trace:` messages on
 616        stderr telling about alias expansion, built-in command
 617        execution and external command execution.
 618        If this variable is set to an integer value greater than 1
 619        and lower than 10 (strictly) then git will interpret this
 620        value as an open file descriptor and will try to write the
 621        trace messages into this file descriptor.
 622        Alternatively, if this variable is set to an absolute path
 623        (starting with a '/' character), git will interpret this
 624        as a file path and will try to write the trace messages
 625        into it.
 626
 627Discussion[[Discussion]]
 628------------------------
 629
 630More detail on the following is available from the
 631link:user-manual.html#git-concepts[git concepts chapter of the
 632user-manual] and linkgit:gitcore-tutorial[7].
 633
 634A git project normally consists of a working directory with a ".git"
 635subdirectory at the top level.  The .git directory contains, among other
 636things, a compressed object database representing the complete history
 637of the project, an "index" file which links that history to the current
 638contents of the working tree, and named pointers into that history such
 639as tags and branch heads.
 640
 641The object database contains objects of three main types: blobs, which
 642hold file data; trees, which point to blobs and other trees to build up
 643directory hierarchies; and commits, which each reference a single tree
 644and some number of parent commits.
 645
 646The commit, equivalent to what other systems call a "changeset" or
 647"version", represents a step in the project's history, and each parent
 648represents an immediately preceding step.  Commits with more than one
 649parent represent merges of independent lines of development.
 650
 651All objects are named by the SHA1 hash of their contents, normally
 652written as a string of 40 hex digits.  Such names are globally unique.
 653The entire history leading up to a commit can be vouched for by signing
 654just that commit.  A fourth object type, the tag, is provided for this
 655purpose.
 656
 657When first created, objects are stored in individual files, but for
 658efficiency may later be compressed together into "pack files".
 659
 660Named pointers called refs mark interesting points in history.  A ref
 661may contain the SHA1 name of an object or the name of another ref.  Refs
 662with names beginning `ref/head/` contain the SHA1 name of the most
 663recent commit (or "head") of a branch under development.  SHA1 names of
 664tags of interest are stored under `ref/tags/`.  A special ref named
 665`HEAD` contains the name of the currently checked-out branch.
 666
 667The index file is initialized with a list of all paths and, for each
 668path, a blob object and a set of attributes.  The blob object represents
 669the contents of the file as of the head of the current branch.  The
 670attributes (last modified time, size, etc.) are taken from the
 671corresponding file in the working tree.  Subsequent changes to the
 672working tree can be found by comparing these attributes.  The index may
 673be updated with new content, and new commits may be created from the
 674content stored in the index.
 675
 676The index is also capable of storing multiple entries (called "stages")
 677for a given pathname.  These stages are used to hold the various
 678unmerged version of a file when a merge is in progress.
 679
 680Authors
 681-------
 682* git's founding father is Linus Torvalds <torvalds@osdl.org>.
 683* The current git nurse is Junio C Hamano <gitster@pobox.com>.
 684* The git potty was written by Andreas Ericsson <ae@op5.se>.
 685* General upbringing is handled by the git-list <git@vger.kernel.org>.
 686
 687Documentation
 688--------------
 689The documentation for git suite was started by David Greaves
 690<david@dgreaves.com>, and later enhanced greatly by the
 691contributors on the git-list <git@vger.kernel.org>.
 692
 693SEE ALSO
 694--------
 695linkgit:gittutorial[7], linkgit:gittutorial-2[7],
 696link:everyday.html[Everyday Git], linkgit:gitcvs-migration[7],
 697linkgit:gitglossary[7], linkgit:gitcore-tutorial[7],
 698linkgit:gitcli[7], link:user-manual.html[The Git User's Manual],
 699linkgit:gitworkflows[7]
 700
 701GIT
 702---
 703Part of the linkgit:git[1] suite