Documentation / git.txton commit Merge branch 'js/diff-verbose-submodule' (d39d667)
   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:v1.6.5.2/git.html[documentation for release 1.6.5.2]
  47
  48* release notes for
  49  link:RelNotes-1.6.5.2.txt[1.6.5.2],
  50  link:RelNotes-1.6.5.1.txt[1.6.5.1],
  51  link:RelNotes-1.6.5.txt[1.6.5].
  52
  53* link:v1.6.4.4/git.html[documentation for release 1.6.4.4]
  54
  55* release notes for
  56  link:RelNotes-1.6.4.4.txt[1.6.4.4],
  57  link:RelNotes-1.6.4.3.txt[1.6.4.3],
  58  link:RelNotes-1.6.4.2.txt[1.6.4.2],
  59  link:RelNotes-1.6.4.1.txt[1.6.4.1],
  60  link:RelNotes-1.6.4.txt[1.6.4].
  61
  62* link:v1.6.3.4/git.html[documentation for release 1.6.3.4]
  63
  64* release notes for
  65  link:RelNotes-1.6.3.4.txt[1.6.3.4],
  66  link:RelNotes-1.6.3.3.txt[1.6.3.3],
  67  link:RelNotes-1.6.3.2.txt[1.6.3.2],
  68  link:RelNotes-1.6.3.1.txt[1.6.3.1],
  69  link:RelNotes-1.6.3.txt[1.6.3].
  70
  71* release notes for
  72  link:RelNotes-1.6.2.5.txt[1.6.2.5],
  73  link:RelNotes-1.6.2.4.txt[1.6.2.4],
  74  link:RelNotes-1.6.2.3.txt[1.6.2.3],
  75  link:RelNotes-1.6.2.2.txt[1.6.2.2],
  76  link:RelNotes-1.6.2.1.txt[1.6.2.1],
  77  link:RelNotes-1.6.2.txt[1.6.2].
  78
  79* link:v1.6.1.3/git.html[documentation for release 1.6.1.3]
  80
  81* release notes for
  82  link:RelNotes-1.6.1.3.txt[1.6.1.3],
  83  link:RelNotes-1.6.1.2.txt[1.6.1.2],
  84  link:RelNotes-1.6.1.1.txt[1.6.1.1],
  85  link:RelNotes-1.6.1.txt[1.6.1].
  86
  87* link:v1.6.0.6/git.html[documentation for release 1.6.0.6]
  88
  89* release notes for
  90  link:RelNotes-1.6.0.6.txt[1.6.0.6],
  91  link:RelNotes-1.6.0.5.txt[1.6.0.5],
  92  link:RelNotes-1.6.0.4.txt[1.6.0.4],
  93  link:RelNotes-1.6.0.3.txt[1.6.0.3],
  94  link:RelNotes-1.6.0.2.txt[1.6.0.2],
  95  link:RelNotes-1.6.0.1.txt[1.6.0.1],
  96  link:RelNotes-1.6.0.txt[1.6.0].
  97
  98* link:v1.5.6.6/git.html[documentation for release 1.5.6.6]
  99
 100* release notes for
 101  link:RelNotes-1.5.6.6.txt[1.5.6.6],
 102  link:RelNotes-1.5.6.5.txt[1.5.6.5],
 103  link:RelNotes-1.5.6.4.txt[1.5.6.4],
 104  link:RelNotes-1.5.6.3.txt[1.5.6.3],
 105  link:RelNotes-1.5.6.2.txt[1.5.6.2],
 106  link:RelNotes-1.5.6.1.txt[1.5.6.1],
 107  link:RelNotes-1.5.6.txt[1.5.6].
 108
 109* link:v1.5.5.6/git.html[documentation for release 1.5.5.6]
 110
 111* release notes for
 112  link:RelNotes-1.5.5.6.txt[1.5.5.6],
 113  link:RelNotes-1.5.5.5.txt[1.5.5.5],
 114  link:RelNotes-1.5.5.4.txt[1.5.5.4],
 115  link:RelNotes-1.5.5.3.txt[1.5.5.3],
 116  link:RelNotes-1.5.5.2.txt[1.5.5.2],
 117  link:RelNotes-1.5.5.1.txt[1.5.5.1],
 118  link:RelNotes-1.5.5.txt[1.5.5].
 119
 120* link:v1.5.4.7/git.html[documentation for release 1.5.4.7]
 121
 122* release notes for
 123  link:RelNotes-1.5.4.7.txt[1.5.4.7],
 124  link:RelNotes-1.5.4.6.txt[1.5.4.6],
 125  link:RelNotes-1.5.4.5.txt[1.5.4.5],
 126  link:RelNotes-1.5.4.4.txt[1.5.4.4],
 127  link:RelNotes-1.5.4.3.txt[1.5.4.3],
 128  link:RelNotes-1.5.4.2.txt[1.5.4.2],
 129  link:RelNotes-1.5.4.1.txt[1.5.4.1],
 130  link:RelNotes-1.5.4.txt[1.5.4].
 131
 132* link:v1.5.3.8/git.html[documentation for release 1.5.3.8]
 133
 134* release notes for
 135  link:RelNotes-1.5.3.8.txt[1.5.3.8],
 136  link:RelNotes-1.5.3.7.txt[1.5.3.7],
 137  link:RelNotes-1.5.3.6.txt[1.5.3.6],
 138  link:RelNotes-1.5.3.5.txt[1.5.3.5],
 139  link:RelNotes-1.5.3.4.txt[1.5.3.4],
 140  link:RelNotes-1.5.3.3.txt[1.5.3.3],
 141  link:RelNotes-1.5.3.2.txt[1.5.3.2],
 142  link:RelNotes-1.5.3.1.txt[1.5.3.1],
 143  link:RelNotes-1.5.3.txt[1.5.3].
 144
 145* link:v1.5.2.5/git.html[documentation for release 1.5.2.5]
 146
 147* release notes for
 148  link:RelNotes-1.5.2.5.txt[1.5.2.5],
 149  link:RelNotes-1.5.2.4.txt[1.5.2.4],
 150  link:RelNotes-1.5.2.3.txt[1.5.2.3],
 151  link:RelNotes-1.5.2.2.txt[1.5.2.2],
 152  link:RelNotes-1.5.2.1.txt[1.5.2.1],
 153  link:RelNotes-1.5.2.txt[1.5.2].
 154
 155* link:v1.5.1.6/git.html[documentation for release 1.5.1.6]
 156
 157* release notes for
 158  link:RelNotes-1.5.1.6.txt[1.5.1.6],
 159  link:RelNotes-1.5.1.5.txt[1.5.1.5],
 160  link:RelNotes-1.5.1.4.txt[1.5.1.4],
 161  link:RelNotes-1.5.1.3.txt[1.5.1.3],
 162  link:RelNotes-1.5.1.2.txt[1.5.1.2],
 163  link:RelNotes-1.5.1.1.txt[1.5.1.1],
 164  link:RelNotes-1.5.1.txt[1.5.1].
 165
 166* link:v1.5.0.7/git.html[documentation for release 1.5.0.7]
 167
 168* release notes for
 169  link:RelNotes-1.5.0.7.txt[1.5.0.7],
 170  link:RelNotes-1.5.0.6.txt[1.5.0.6],
 171  link:RelNotes-1.5.0.5.txt[1.5.0.5],
 172  link:RelNotes-1.5.0.3.txt[1.5.0.3],
 173  link:RelNotes-1.5.0.2.txt[1.5.0.2],
 174  link:RelNotes-1.5.0.1.txt[1.5.0.1],
 175  link:RelNotes-1.5.0.txt[1.5.0].
 176
 177* documentation for release link:v1.4.4.4/git.html[1.4.4.4],
 178  link:v1.3.3/git.html[1.3.3],
 179  link:v1.2.6/git.html[1.2.6],
 180  link:v1.0.13/git.html[1.0.13].
 181
 182============
 183
 184endif::stalenotes[]
 185
 186OPTIONS
 187-------
 188--version::
 189        Prints the git suite version that the 'git' program came from.
 190
 191--help::
 192        Prints the synopsis and a list of the most commonly used
 193        commands. If the option '--all' or '-a' is given then all
 194        available commands are printed. If a git command is named this
 195        option will bring up the manual page for that command.
 196+
 197Other options are available to control how the manual page is
 198displayed. See linkgit:git-help[1] for more information,
 199because `git --help ...` is converted internally into `git
 200help ...`.
 201
 202--exec-path::
 203        Path to wherever your core git programs are installed.
 204        This can also be controlled by setting the GIT_EXEC_PATH
 205        environment variable. If no path is given, 'git' will print
 206        the current setting and then exit.
 207
 208--html-path::
 209        Print the path to wherever your git HTML documentation is installed
 210        and exit.
 211
 212-p::
 213--paginate::
 214        Pipe all output into 'less' (or if set, $PAGER).
 215
 216--no-pager::
 217        Do not pipe git output into a pager.
 218
 219--git-dir=<path>::
 220        Set the path to the repository. This can also be controlled by
 221        setting the GIT_DIR environment variable. It can be an absolute
 222        path or relative path to current working directory.
 223
 224--work-tree=<path>::
 225        Set the path to the working tree.  The value will not be
 226        used in combination with repositories found automatically in
 227        a .git directory (i.e. $GIT_DIR is not set).
 228        This can also be controlled by setting the GIT_WORK_TREE
 229        environment variable and the core.worktree configuration
 230        variable. It can be an absolute path or relative path to
 231        the directory specified by --git-dir or GIT_DIR.
 232        Note: If --git-dir or GIT_DIR are specified but none of
 233        --work-tree, GIT_WORK_TREE and core.worktree is specified,
 234        the current working directory is regarded as the top directory
 235        of your working tree.
 236
 237--bare::
 238        Treat the repository as a bare repository.  If GIT_DIR
 239        environment is not set, it is set to the current working
 240        directory.
 241
 242--no-replace-objects::
 243        Do not use replacement refs to replace git objects. See
 244        linkgit:git-replace[1] for more information.
 245
 246
 247FURTHER DOCUMENTATION
 248---------------------
 249
 250See the references above to get started using git.  The following is
 251probably more detail than necessary for a first-time user.
 252
 253The link:user-manual.html#git-concepts[git concepts chapter of the
 254user-manual] and linkgit:gitcore-tutorial[7] both provide
 255introductions to the underlying git architecture.
 256
 257See linkgit:gitworkflows[7] for an overview of recommended workflows.
 258
 259See also the link:howto-index.html[howto] documents for some useful
 260examples.
 261
 262The internals are documented in the
 263link:technical/api-index.html[GIT API documentation].
 264
 265GIT COMMANDS
 266------------
 267
 268We divide git into high level ("porcelain") commands and low level
 269("plumbing") commands.
 270
 271High-level commands (porcelain)
 272-------------------------------
 273
 274We separate the porcelain commands into the main commands and some
 275ancillary user utilities.
 276
 277Main porcelain commands
 278~~~~~~~~~~~~~~~~~~~~~~~
 279
 280include::cmds-mainporcelain.txt[]
 281
 282Ancillary Commands
 283~~~~~~~~~~~~~~~~~~
 284Manipulators:
 285
 286include::cmds-ancillarymanipulators.txt[]
 287
 288Interrogators:
 289
 290include::cmds-ancillaryinterrogators.txt[]
 291
 292
 293Interacting with Others
 294~~~~~~~~~~~~~~~~~~~~~~~
 295
 296These commands are to interact with foreign SCM and with other
 297people via patch over e-mail.
 298
 299include::cmds-foreignscminterface.txt[]
 300
 301
 302Low-level commands (plumbing)
 303-----------------------------
 304
 305Although git includes its
 306own porcelain layer, its low-level commands are sufficient to support
 307development of alternative porcelains.  Developers of such porcelains
 308might start by reading about linkgit:git-update-index[1] and
 309linkgit:git-read-tree[1].
 310
 311The interface (input, output, set of options and the semantics)
 312to these low-level commands are meant to be a lot more stable
 313than Porcelain level commands, because these commands are
 314primarily for scripted use.  The interface to Porcelain commands
 315on the other hand are subject to change in order to improve the
 316end user experience.
 317
 318The following description divides
 319the low-level commands into commands that manipulate objects (in
 320the repository, index, and working tree), commands that interrogate and
 321compare objects, and commands that move objects and references between
 322repositories.
 323
 324
 325Manipulation commands
 326~~~~~~~~~~~~~~~~~~~~~
 327
 328include::cmds-plumbingmanipulators.txt[]
 329
 330
 331Interrogation commands
 332~~~~~~~~~~~~~~~~~~~~~~
 333
 334include::cmds-plumbinginterrogators.txt[]
 335
 336In general, the interrogate commands do not touch the files in
 337the working tree.
 338
 339
 340Synching repositories
 341~~~~~~~~~~~~~~~~~~~~~
 342
 343include::cmds-synchingrepositories.txt[]
 344
 345The following are helper commands used by the above; end users
 346typically do not use them directly.
 347
 348include::cmds-synchelpers.txt[]
 349
 350
 351Internal helper commands
 352~~~~~~~~~~~~~~~~~~~~~~~~
 353
 354These are internal helper commands used by other commands; end
 355users typically do not use them directly.
 356
 357include::cmds-purehelpers.txt[]
 358
 359
 360Configuration Mechanism
 361-----------------------
 362
 363Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file
 364is used to hold per-repository configuration options.  It is a
 365simple text file modeled after `.ini` format familiar to some
 366people.  Here is an example:
 367
 368------------
 369#
 370# A '#' or ';' character indicates a comment.
 371#
 372
 373; core variables
 374[core]
 375        ; Don't trust file modes
 376        filemode = false
 377
 378; user identity
 379[user]
 380        name = "Junio C Hamano"
 381        email = "junkio@twinsun.com"
 382
 383------------
 384
 385Various commands read from the configuration file and adjust
 386their operation accordingly.
 387
 388
 389Identifier Terminology
 390----------------------
 391<object>::
 392        Indicates the object name for any type of object.
 393
 394<blob>::
 395        Indicates a blob object name.
 396
 397<tree>::
 398        Indicates a tree object name.
 399
 400<commit>::
 401        Indicates a commit object name.
 402
 403<tree-ish>::
 404        Indicates a tree, commit or tag object name.  A
 405        command that takes a <tree-ish> argument ultimately wants to
 406        operate on a <tree> object but automatically dereferences
 407        <commit> and <tag> objects that point at a <tree>.
 408
 409<commit-ish>::
 410        Indicates a commit or tag object name.  A
 411        command that takes a <commit-ish> argument ultimately wants to
 412        operate on a <commit> object but automatically dereferences
 413        <tag> objects that point at a <commit>.
 414
 415<type>::
 416        Indicates that an object type is required.
 417        Currently one of: `blob`, `tree`, `commit`, or `tag`.
 418
 419<file>::
 420        Indicates a filename - almost always relative to the
 421        root of the tree structure `GIT_INDEX_FILE` describes.
 422
 423Symbolic Identifiers
 424--------------------
 425Any git command accepting any <object> can also use the following
 426symbolic notation:
 427
 428HEAD::
 429        indicates the head of the current branch (i.e. the
 430        contents of `$GIT_DIR/HEAD`).
 431
 432<tag>::
 433        a valid tag 'name'
 434        (i.e. the contents of `$GIT_DIR/refs/tags/<tag>`).
 435
 436<head>::
 437        a valid head 'name'
 438        (i.e. the contents of `$GIT_DIR/refs/heads/<head>`).
 439
 440For a more complete list of ways to spell object names, see
 441"SPECIFYING REVISIONS" section in linkgit:git-rev-parse[1].
 442
 443
 444File/Directory Structure
 445------------------------
 446
 447Please see the linkgit:gitrepository-layout[5] document.
 448
 449Read linkgit:githooks[5] for more details about each hook.
 450
 451Higher level SCMs may provide and manage additional information in the
 452`$GIT_DIR`.
 453
 454
 455Terminology
 456-----------
 457Please see linkgit:gitglossary[7].
 458
 459
 460Environment Variables
 461---------------------
 462Various git commands use the following environment variables:
 463
 464The git Repository
 465~~~~~~~~~~~~~~~~~~
 466These environment variables apply to 'all' core git commands. Nb: it
 467is worth noting that they may be used/overridden by SCMS sitting above
 468git so take care if using Cogito etc.
 469
 470'GIT_INDEX_FILE'::
 471        This environment allows the specification of an alternate
 472        index file. If not specified, the default of `$GIT_DIR/index`
 473        is used.
 474
 475'GIT_OBJECT_DIRECTORY'::
 476        If the object storage directory is specified via this
 477        environment variable then the sha1 directories are created
 478        underneath - otherwise the default `$GIT_DIR/objects`
 479        directory is used.
 480
 481'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
 482        Due to the immutable nature of git objects, old objects can be
 483        archived into shared, read-only directories. This variable
 484        specifies a ":" separated (on Windows ";" separated) list
 485        of git object directories which can be used to search for git
 486        objects. New objects will not be written to these directories.
 487
 488'GIT_DIR'::
 489        If the 'GIT_DIR' environment variable is set then it
 490        specifies a path to use instead of the default `.git`
 491        for the base of the repository.
 492
 493'GIT_WORK_TREE'::
 494        Set the path to the working tree.  The value will not be
 495        used in combination with repositories found automatically in
 496        a .git directory (i.e. $GIT_DIR is not set).
 497        This can also be controlled by the '--work-tree' command line
 498        option and the core.worktree configuration variable.
 499
 500'GIT_CEILING_DIRECTORIES'::
 501        This should be a colon-separated list of absolute paths.
 502        If set, it is a list of directories that git should not chdir
 503        up into while looking for a repository directory.
 504        It will not exclude the current working directory or
 505        a GIT_DIR set on the command line or in the environment.
 506        (Useful for excluding slow-loading network directories.)
 507
 508git Commits
 509~~~~~~~~~~~
 510'GIT_AUTHOR_NAME'::
 511'GIT_AUTHOR_EMAIL'::
 512'GIT_AUTHOR_DATE'::
 513'GIT_COMMITTER_NAME'::
 514'GIT_COMMITTER_EMAIL'::
 515'GIT_COMMITTER_DATE'::
 516'EMAIL'::
 517        see linkgit:git-commit-tree[1]
 518
 519git Diffs
 520~~~~~~~~~
 521'GIT_DIFF_OPTS'::
 522        Only valid setting is "--unified=??" or "-u??" to set the
 523        number of context lines shown when a unified diff is created.
 524        This takes precedence over any "-U" or "--unified" option
 525        value passed on the git diff command line.
 526
 527'GIT_EXTERNAL_DIFF'::
 528        When the environment variable 'GIT_EXTERNAL_DIFF' is set, the
 529        program named by it is called, instead of the diff invocation
 530        described above.  For a path that is added, removed, or modified,
 531        'GIT_EXTERNAL_DIFF' is called with 7 parameters:
 532
 533        path old-file old-hex old-mode new-file new-hex new-mode
 534+
 535where:
 536
 537        <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the
 538                         contents of <old|new>,
 539        <old|new>-hex:: are the 40-hexdigit SHA1 hashes,
 540        <old|new>-mode:: are the octal representation of the file modes.
 541
 542+
 543The file parameters can point at the user's working file
 544(e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
 545when a new file is added), or a temporary file (e.g. `old-file` in the
 546index).  'GIT_EXTERNAL_DIFF' should not worry about unlinking the
 547temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits.
 548+
 549For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1
 550parameter, <path>.
 551
 552other
 553~~~~~
 554'GIT_MERGE_VERBOSITY'::
 555        A number controlling the amount of output shown by
 556        the recursive merge strategy.  Overrides merge.verbosity.
 557        See linkgit:git-merge[1]
 558
 559'GIT_PAGER'::
 560        This environment variable overrides `$PAGER`. If it is set
 561        to an empty string or to the value "cat", git will not launch
 562        a pager.  See also the `core.pager` option in
 563        linkgit:git-config[1].
 564
 565'GIT_SSH'::
 566        If this environment variable is set then 'git-fetch'
 567        and 'git-push' will use this command instead
 568        of 'ssh' when they need to connect to a remote system.
 569        The '$GIT_SSH' command will be given exactly two arguments:
 570        the 'username@host' (or just 'host') from the URL and the
 571        shell command to execute on that remote system.
 572+
 573To pass options to the program that you want to list in GIT_SSH
 574you will need to wrap the program and options into a shell script,
 575then set GIT_SSH to refer to the shell script.
 576+
 577Usually it is easier to configure any desired options through your
 578personal `.ssh/config` file.  Please consult your ssh documentation
 579for further details.
 580
 581'GIT_FLUSH'::
 582        If this environment variable is set to "1", then commands such
 583        as 'git-blame' (in incremental mode), 'git-rev-list', 'git-log',
 584        and 'git-whatchanged' will force a flush of the output stream
 585        after each commit-oriented record have been flushed.   If this
 586        variable is set to "0", the output of these commands will be done
 587        using completely buffered I/O.   If this environment variable is
 588        not set, git will choose buffered or record-oriented flushing
 589        based on whether stdout appears to be redirected to a file or not.
 590
 591'GIT_TRACE'::
 592        If this variable is set to "1", "2" or "true" (comparison
 593        is case insensitive), git will print `trace:` messages on
 594        stderr telling about alias expansion, built-in command
 595        execution and external command execution.
 596        If this variable is set to an integer value greater than 1
 597        and lower than 10 (strictly) then git will interpret this
 598        value as an open file descriptor and will try to write the
 599        trace messages into this file descriptor.
 600        Alternatively, if this variable is set to an absolute path
 601        (starting with a '/' character), git will interpret this
 602        as a file path and will try to write the trace messages
 603        into it.
 604
 605Discussion[[Discussion]]
 606------------------------
 607
 608More detail on the following is available from the
 609link:user-manual.html#git-concepts[git concepts chapter of the
 610user-manual] and linkgit:gitcore-tutorial[7].
 611
 612A git project normally consists of a working directory with a ".git"
 613subdirectory at the top level.  The .git directory contains, among other
 614things, a compressed object database representing the complete history
 615of the project, an "index" file which links that history to the current
 616contents of the working tree, and named pointers into that history such
 617as tags and branch heads.
 618
 619The object database contains objects of three main types: blobs, which
 620hold file data; trees, which point to blobs and other trees to build up
 621directory hierarchies; and commits, which each reference a single tree
 622and some number of parent commits.
 623
 624The commit, equivalent to what other systems call a "changeset" or
 625"version", represents a step in the project's history, and each parent
 626represents an immediately preceding step.  Commits with more than one
 627parent represent merges of independent lines of development.
 628
 629All objects are named by the SHA1 hash of their contents, normally
 630written as a string of 40 hex digits.  Such names are globally unique.
 631The entire history leading up to a commit can be vouched for by signing
 632just that commit.  A fourth object type, the tag, is provided for this
 633purpose.
 634
 635When first created, objects are stored in individual files, but for
 636efficiency may later be compressed together into "pack files".
 637
 638Named pointers called refs mark interesting points in history.  A ref
 639may contain the SHA1 name of an object or the name of another ref.  Refs
 640with names beginning `ref/head/` contain the SHA1 name of the most
 641recent commit (or "head") of a branch under development.  SHA1 names of
 642tags of interest are stored under `ref/tags/`.  A special ref named
 643`HEAD` contains the name of the currently checked-out branch.
 644
 645The index file is initialized with a list of all paths and, for each
 646path, a blob object and a set of attributes.  The blob object represents
 647the contents of the file as of the head of the current branch.  The
 648attributes (last modified time, size, etc.) are taken from the
 649corresponding file in the working tree.  Subsequent changes to the
 650working tree can be found by comparing these attributes.  The index may
 651be updated with new content, and new commits may be created from the
 652content stored in the index.
 653
 654The index is also capable of storing multiple entries (called "stages")
 655for a given pathname.  These stages are used to hold the various
 656unmerged version of a file when a merge is in progress.
 657
 658Authors
 659-------
 660* git's founding father is Linus Torvalds <torvalds@osdl.org>.
 661* The current git nurse is Junio C Hamano <gitster@pobox.com>.
 662* The git potty was written by Andreas Ericsson <ae@op5.se>.
 663* General upbringing is handled by the git-list <git@vger.kernel.org>.
 664
 665Documentation
 666--------------
 667The documentation for git suite was started by David Greaves
 668<david@dgreaves.com>, and later enhanced greatly by the
 669contributors on the git-list <git@vger.kernel.org>.
 670
 671SEE ALSO
 672--------
 673linkgit:gittutorial[7], linkgit:gittutorial-2[7],
 674link:everyday.html[Everyday Git], linkgit:gitcvs-migration[7],
 675linkgit:gitglossary[7], linkgit:gitcore-tutorial[7],
 676linkgit:gitcli[7], link:user-manual.html[The Git User's Manual],
 677linkgit:gitworkflows[7]
 678
 679GIT
 680---
 681Part of the linkgit:git[1] suite