Documentation / git.txton commit Merge branch 'bg/rebase-reword' (e79999b)
   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/git.html[documentation for release 1.6.5]
  47
  48* release notes for
  49  link:RelNotes-1.6.5.1.txt[1.6.5.1],
  50  link:RelNotes-1.6.5.txt[1.6.5].
  51
  52* link:v1.6.4.4/git.html[documentation for release 1.6.4.4]
  53
  54* release notes for
  55  link:RelNotes-1.6.4.4.txt[1.6.4.4],
  56  link:RelNotes-1.6.4.3.txt[1.6.4.3],
  57  link:RelNotes-1.6.4.2.txt[1.6.4.2],
  58  link:RelNotes-1.6.4.1.txt[1.6.4.1],
  59  link:RelNotes-1.6.4.txt[1.6.4].
  60
  61* link:v1.6.3.4/git.html[documentation for release 1.6.3.4]
  62
  63* release notes for
  64  link:RelNotes-1.6.3.4.txt[1.6.3.4],
  65  link:RelNotes-1.6.3.3.txt[1.6.3.3],
  66  link:RelNotes-1.6.3.2.txt[1.6.3.2],
  67  link:RelNotes-1.6.3.1.txt[1.6.3.1],
  68  link:RelNotes-1.6.3.txt[1.6.3].
  69
  70* release notes for
  71  link:RelNotes-1.6.2.5.txt[1.6.2.5],
  72  link:RelNotes-1.6.2.4.txt[1.6.2.4],
  73  link:RelNotes-1.6.2.3.txt[1.6.2.3],
  74  link:RelNotes-1.6.2.2.txt[1.6.2.2],
  75  link:RelNotes-1.6.2.1.txt[1.6.2.1],
  76  link:RelNotes-1.6.2.txt[1.6.2].
  77
  78* link:v1.6.1.3/git.html[documentation for release 1.6.1.3]
  79
  80* release notes for
  81  link:RelNotes-1.6.1.3.txt[1.6.1.3],
  82  link:RelNotes-1.6.1.2.txt[1.6.1.2],
  83  link:RelNotes-1.6.1.1.txt[1.6.1.1],
  84  link:RelNotes-1.6.1.txt[1.6.1].
  85
  86* link:v1.6.0.6/git.html[documentation for release 1.6.0.6]
  87
  88* release notes for
  89  link:RelNotes-1.6.0.6.txt[1.6.0.6],
  90  link:RelNotes-1.6.0.5.txt[1.6.0.5],
  91  link:RelNotes-1.6.0.4.txt[1.6.0.4],
  92  link:RelNotes-1.6.0.3.txt[1.6.0.3],
  93  link:RelNotes-1.6.0.2.txt[1.6.0.2],
  94  link:RelNotes-1.6.0.1.txt[1.6.0.1],
  95  link:RelNotes-1.6.0.txt[1.6.0].
  96
  97* link:v1.5.6.6/git.html[documentation for release 1.5.6.6]
  98
  99* release notes for
 100  link:RelNotes-1.5.6.6.txt[1.5.6.6],
 101  link:RelNotes-1.5.6.5.txt[1.5.6.5],
 102  link:RelNotes-1.5.6.4.txt[1.5.6.4],
 103  link:RelNotes-1.5.6.3.txt[1.5.6.3],
 104  link:RelNotes-1.5.6.2.txt[1.5.6.2],
 105  link:RelNotes-1.5.6.1.txt[1.5.6.1],
 106  link:RelNotes-1.5.6.txt[1.5.6].
 107
 108* link:v1.5.5.6/git.html[documentation for release 1.5.5.6]
 109
 110* release notes for
 111  link:RelNotes-1.5.5.6.txt[1.5.5.6],
 112  link:RelNotes-1.5.5.5.txt[1.5.5.5],
 113  link:RelNotes-1.5.5.4.txt[1.5.5.4],
 114  link:RelNotes-1.5.5.3.txt[1.5.5.3],
 115  link:RelNotes-1.5.5.2.txt[1.5.5.2],
 116  link:RelNotes-1.5.5.1.txt[1.5.5.1],
 117  link:RelNotes-1.5.5.txt[1.5.5].
 118
 119* link:v1.5.4.7/git.html[documentation for release 1.5.4.7]
 120
 121* release notes for
 122  link:RelNotes-1.5.4.7.txt[1.5.4.7],
 123  link:RelNotes-1.5.4.6.txt[1.5.4.6],
 124  link:RelNotes-1.5.4.5.txt[1.5.4.5],
 125  link:RelNotes-1.5.4.4.txt[1.5.4.4],
 126  link:RelNotes-1.5.4.3.txt[1.5.4.3],
 127  link:RelNotes-1.5.4.2.txt[1.5.4.2],
 128  link:RelNotes-1.5.4.1.txt[1.5.4.1],
 129  link:RelNotes-1.5.4.txt[1.5.4].
 130
 131* link:v1.5.3.8/git.html[documentation for release 1.5.3.8]
 132
 133* release notes for
 134  link:RelNotes-1.5.3.8.txt[1.5.3.8],
 135  link:RelNotes-1.5.3.7.txt[1.5.3.7],
 136  link:RelNotes-1.5.3.6.txt[1.5.3.6],
 137  link:RelNotes-1.5.3.5.txt[1.5.3.5],
 138  link:RelNotes-1.5.3.4.txt[1.5.3.4],
 139  link:RelNotes-1.5.3.3.txt[1.5.3.3],
 140  link:RelNotes-1.5.3.2.txt[1.5.3.2],
 141  link:RelNotes-1.5.3.1.txt[1.5.3.1],
 142  link:RelNotes-1.5.3.txt[1.5.3].
 143
 144* link:v1.5.2.5/git.html[documentation for release 1.5.2.5]
 145
 146* release notes for
 147  link:RelNotes-1.5.2.5.txt[1.5.2.5],
 148  link:RelNotes-1.5.2.4.txt[1.5.2.4],
 149  link:RelNotes-1.5.2.3.txt[1.5.2.3],
 150  link:RelNotes-1.5.2.2.txt[1.5.2.2],
 151  link:RelNotes-1.5.2.1.txt[1.5.2.1],
 152  link:RelNotes-1.5.2.txt[1.5.2].
 153
 154* link:v1.5.1.6/git.html[documentation for release 1.5.1.6]
 155
 156* release notes for
 157  link:RelNotes-1.5.1.6.txt[1.5.1.6],
 158  link:RelNotes-1.5.1.5.txt[1.5.1.5],
 159  link:RelNotes-1.5.1.4.txt[1.5.1.4],
 160  link:RelNotes-1.5.1.3.txt[1.5.1.3],
 161  link:RelNotes-1.5.1.2.txt[1.5.1.2],
 162  link:RelNotes-1.5.1.1.txt[1.5.1.1],
 163  link:RelNotes-1.5.1.txt[1.5.1].
 164
 165* link:v1.5.0.7/git.html[documentation for release 1.5.0.7]
 166
 167* release notes for
 168  link:RelNotes-1.5.0.7.txt[1.5.0.7],
 169  link:RelNotes-1.5.0.6.txt[1.5.0.6],
 170  link:RelNotes-1.5.0.5.txt[1.5.0.5],
 171  link:RelNotes-1.5.0.3.txt[1.5.0.3],
 172  link:RelNotes-1.5.0.2.txt[1.5.0.2],
 173  link:RelNotes-1.5.0.1.txt[1.5.0.1],
 174  link:RelNotes-1.5.0.txt[1.5.0].
 175
 176* documentation for release link:v1.4.4.4/git.html[1.4.4.4],
 177  link:v1.3.3/git.html[1.3.3],
 178  link:v1.2.6/git.html[1.2.6],
 179  link:v1.0.13/git.html[1.0.13].
 180
 181============
 182
 183endif::stalenotes[]
 184
 185OPTIONS
 186-------
 187--version::
 188        Prints the git suite version that the 'git' program came from.
 189
 190--help::
 191        Prints the synopsis and a list of the most commonly used
 192        commands. If the option '--all' or '-a' is given then all
 193        available commands are printed. If a git command is named this
 194        option will bring up the manual page for that command.
 195+
 196Other options are available to control how the manual page is
 197displayed. See linkgit:git-help[1] for more information,
 198because `git --help ...` is converted internally into `git
 199help ...`.
 200
 201--exec-path::
 202        Path to wherever your core git programs are installed.
 203        This can also be controlled by setting the GIT_EXEC_PATH
 204        environment variable. If no path is given, 'git' will print
 205        the current setting and then exit.
 206
 207--html-path::
 208        Print the path to wherever your git HTML documentation is installed
 209        and exit.
 210
 211-p::
 212--paginate::
 213        Pipe all output into 'less' (or if set, $PAGER).
 214
 215--no-pager::
 216        Do not pipe git output into a pager.
 217
 218--git-dir=<path>::
 219        Set the path to the repository. This can also be controlled by
 220        setting the GIT_DIR environment variable. It can be an absolute
 221        path or relative path to current working directory.
 222
 223--work-tree=<path>::
 224        Set the path to the working tree.  The value will not be
 225        used in combination with repositories found automatically in
 226        a .git directory (i.e. $GIT_DIR is not set).
 227        This can also be controlled by setting the GIT_WORK_TREE
 228        environment variable and the core.worktree configuration
 229        variable. It can be an absolute path or relative path to
 230        the directory specified by --git-dir or GIT_DIR.
 231        Note: If --git-dir or GIT_DIR are specified but none of
 232        --work-tree, GIT_WORK_TREE and core.worktree is specified,
 233        the current working directory is regarded as the top directory
 234        of your working tree.
 235
 236--bare::
 237        Treat the repository as a bare repository.  If GIT_DIR
 238        environment is not set, it is set to the current working
 239        directory.
 240
 241--no-replace-objects::
 242        Do not use replacement refs to replace git objects. See
 243        linkgit:git-replace[1] for more information.
 244
 245
 246FURTHER DOCUMENTATION
 247---------------------
 248
 249See the references above to get started using git.  The following is
 250probably more detail than necessary for a first-time user.
 251
 252The link:user-manual.html#git-concepts[git concepts chapter of the
 253user-manual] and linkgit:gitcore-tutorial[7] both provide
 254introductions to the underlying git architecture.
 255
 256See linkgit:gitworkflows[7] for an overview of recommended workflows.
 257
 258See also the link:howto-index.html[howto] documents for some useful
 259examples.
 260
 261The internals are documented in the
 262link:technical/api-index.html[GIT API documentation].
 263
 264GIT COMMANDS
 265------------
 266
 267We divide git into high level ("porcelain") commands and low level
 268("plumbing") commands.
 269
 270High-level commands (porcelain)
 271-------------------------------
 272
 273We separate the porcelain commands into the main commands and some
 274ancillary user utilities.
 275
 276Main porcelain commands
 277~~~~~~~~~~~~~~~~~~~~~~~
 278
 279include::cmds-mainporcelain.txt[]
 280
 281Ancillary Commands
 282~~~~~~~~~~~~~~~~~~
 283Manipulators:
 284
 285include::cmds-ancillarymanipulators.txt[]
 286
 287Interrogators:
 288
 289include::cmds-ancillaryinterrogators.txt[]
 290
 291
 292Interacting with Others
 293~~~~~~~~~~~~~~~~~~~~~~~
 294
 295These commands are to interact with foreign SCM and with other
 296people via patch over e-mail.
 297
 298include::cmds-foreignscminterface.txt[]
 299
 300
 301Low-level commands (plumbing)
 302-----------------------------
 303
 304Although git includes its
 305own porcelain layer, its low-level commands are sufficient to support
 306development of alternative porcelains.  Developers of such porcelains
 307might start by reading about linkgit:git-update-index[1] and
 308linkgit:git-read-tree[1].
 309
 310The interface (input, output, set of options and the semantics)
 311to these low-level commands are meant to be a lot more stable
 312than Porcelain level commands, because these commands are
 313primarily for scripted use.  The interface to Porcelain commands
 314on the other hand are subject to change in order to improve the
 315end user experience.
 316
 317The following description divides
 318the low-level commands into commands that manipulate objects (in
 319the repository, index, and working tree), commands that interrogate and
 320compare objects, and commands that move objects and references between
 321repositories.
 322
 323
 324Manipulation commands
 325~~~~~~~~~~~~~~~~~~~~~
 326
 327include::cmds-plumbingmanipulators.txt[]
 328
 329
 330Interrogation commands
 331~~~~~~~~~~~~~~~~~~~~~~
 332
 333include::cmds-plumbinginterrogators.txt[]
 334
 335In general, the interrogate commands do not touch the files in
 336the working tree.
 337
 338
 339Synching repositories
 340~~~~~~~~~~~~~~~~~~~~~
 341
 342include::cmds-synchingrepositories.txt[]
 343
 344The following are helper commands used by the above; end users
 345typically do not use them directly.
 346
 347include::cmds-synchelpers.txt[]
 348
 349
 350Internal helper commands
 351~~~~~~~~~~~~~~~~~~~~~~~~
 352
 353These are internal helper commands used by other commands; end
 354users typically do not use them directly.
 355
 356include::cmds-purehelpers.txt[]
 357
 358
 359Configuration Mechanism
 360-----------------------
 361
 362Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file
 363is used to hold per-repository configuration options.  It is a
 364simple text file modeled after `.ini` format familiar to some
 365people.  Here is an example:
 366
 367------------
 368#
 369# A '#' or ';' character indicates a comment.
 370#
 371
 372; core variables
 373[core]
 374        ; Don't trust file modes
 375        filemode = false
 376
 377; user identity
 378[user]
 379        name = "Junio C Hamano"
 380        email = "junkio@twinsun.com"
 381
 382------------
 383
 384Various commands read from the configuration file and adjust
 385their operation accordingly.
 386
 387
 388Identifier Terminology
 389----------------------
 390<object>::
 391        Indicates the object name for any type of object.
 392
 393<blob>::
 394        Indicates a blob object name.
 395
 396<tree>::
 397        Indicates a tree object name.
 398
 399<commit>::
 400        Indicates a commit object name.
 401
 402<tree-ish>::
 403        Indicates a tree, commit or tag object name.  A
 404        command that takes a <tree-ish> argument ultimately wants to
 405        operate on a <tree> object but automatically dereferences
 406        <commit> and <tag> objects that point at a <tree>.
 407
 408<commit-ish>::
 409        Indicates a commit or tag object name.  A
 410        command that takes a <commit-ish> argument ultimately wants to
 411        operate on a <commit> object but automatically dereferences
 412        <tag> objects that point at a <commit>.
 413
 414<type>::
 415        Indicates that an object type is required.
 416        Currently one of: `blob`, `tree`, `commit`, or `tag`.
 417
 418<file>::
 419        Indicates a filename - almost always relative to the
 420        root of the tree structure `GIT_INDEX_FILE` describes.
 421
 422Symbolic Identifiers
 423--------------------
 424Any git command accepting any <object> can also use the following
 425symbolic notation:
 426
 427HEAD::
 428        indicates the head of the current branch (i.e. the
 429        contents of `$GIT_DIR/HEAD`).
 430
 431<tag>::
 432        a valid tag 'name'
 433        (i.e. the contents of `$GIT_DIR/refs/tags/<tag>`).
 434
 435<head>::
 436        a valid head 'name'
 437        (i.e. the contents of `$GIT_DIR/refs/heads/<head>`).
 438
 439For a more complete list of ways to spell object names, see
 440"SPECIFYING REVISIONS" section in linkgit:git-rev-parse[1].
 441
 442
 443File/Directory Structure
 444------------------------
 445
 446Please see the linkgit:gitrepository-layout[5] document.
 447
 448Read linkgit:githooks[5] for more details about each hook.
 449
 450Higher level SCMs may provide and manage additional information in the
 451`$GIT_DIR`.
 452
 453
 454Terminology
 455-----------
 456Please see linkgit:gitglossary[7].
 457
 458
 459Environment Variables
 460---------------------
 461Various git commands use the following environment variables:
 462
 463The git Repository
 464~~~~~~~~~~~~~~~~~~
 465These environment variables apply to 'all' core git commands. Nb: it
 466is worth noting that they may be used/overridden by SCMS sitting above
 467git so take care if using Cogito etc.
 468
 469'GIT_INDEX_FILE'::
 470        This environment allows the specification of an alternate
 471        index file. If not specified, the default of `$GIT_DIR/index`
 472        is used.
 473
 474'GIT_OBJECT_DIRECTORY'::
 475        If the object storage directory is specified via this
 476        environment variable then the sha1 directories are created
 477        underneath - otherwise the default `$GIT_DIR/objects`
 478        directory is used.
 479
 480'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
 481        Due to the immutable nature of git objects, old objects can be
 482        archived into shared, read-only directories. This variable
 483        specifies a ":" separated (on Windows ";" separated) list
 484        of git object directories which can be used to search for git
 485        objects. New objects will not be written to these directories.
 486
 487'GIT_DIR'::
 488        If the 'GIT_DIR' environment variable is set then it
 489        specifies a path to use instead of the default `.git`
 490        for the base of the repository.
 491
 492'GIT_WORK_TREE'::
 493        Set the path to the working tree.  The value will not be
 494        used in combination with repositories found automatically in
 495        a .git directory (i.e. $GIT_DIR is not set).
 496        This can also be controlled by the '--work-tree' command line
 497        option and the core.worktree configuration variable.
 498
 499'GIT_CEILING_DIRECTORIES'::
 500        This should be a colon-separated list of absolute paths.
 501        If set, it is a list of directories that git should not chdir
 502        up into while looking for a repository directory.
 503        It will not exclude the current working directory or
 504        a GIT_DIR set on the command line or in the environment.
 505        (Useful for excluding slow-loading network directories.)
 506
 507git Commits
 508~~~~~~~~~~~
 509'GIT_AUTHOR_NAME'::
 510'GIT_AUTHOR_EMAIL'::
 511'GIT_AUTHOR_DATE'::
 512'GIT_COMMITTER_NAME'::
 513'GIT_COMMITTER_EMAIL'::
 514'GIT_COMMITTER_DATE'::
 515'EMAIL'::
 516        see linkgit:git-commit-tree[1]
 517
 518git Diffs
 519~~~~~~~~~
 520'GIT_DIFF_OPTS'::
 521        Only valid setting is "--unified=??" or "-u??" to set the
 522        number of context lines shown when a unified diff is created.
 523        This takes precedence over any "-U" or "--unified" option
 524        value passed on the git diff command line.
 525
 526'GIT_EXTERNAL_DIFF'::
 527        When the environment variable 'GIT_EXTERNAL_DIFF' is set, the
 528        program named by it is called, instead of the diff invocation
 529        described above.  For a path that is added, removed, or modified,
 530        'GIT_EXTERNAL_DIFF' is called with 7 parameters:
 531
 532        path old-file old-hex old-mode new-file new-hex new-mode
 533+
 534where:
 535
 536        <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the
 537                         contents of <old|new>,
 538        <old|new>-hex:: are the 40-hexdigit SHA1 hashes,
 539        <old|new>-mode:: are the octal representation of the file modes.
 540
 541+
 542The file parameters can point at the user's working file
 543(e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
 544when a new file is added), or a temporary file (e.g. `old-file` in the
 545index).  'GIT_EXTERNAL_DIFF' should not worry about unlinking the
 546temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits.
 547+
 548For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1
 549parameter, <path>.
 550
 551other
 552~~~~~
 553'GIT_MERGE_VERBOSITY'::
 554        A number controlling the amount of output shown by
 555        the recursive merge strategy.  Overrides merge.verbosity.
 556        See linkgit:git-merge[1]
 557
 558'GIT_PAGER'::
 559        This environment variable overrides `$PAGER`. If it is set
 560        to an empty string or to the value "cat", git will not launch
 561        a pager.  See also the `core.pager` option in
 562        linkgit:git-config[1].
 563
 564'GIT_SSH'::
 565        If this environment variable is set then 'git-fetch'
 566        and 'git-push' will use this command instead
 567        of 'ssh' when they need to connect to a remote system.
 568        The '$GIT_SSH' command will be given exactly two arguments:
 569        the 'username@host' (or just 'host') from the URL and the
 570        shell command to execute on that remote system.
 571+
 572To pass options to the program that you want to list in GIT_SSH
 573you will need to wrap the program and options into a shell script,
 574then set GIT_SSH to refer to the shell script.
 575+
 576Usually it is easier to configure any desired options through your
 577personal `.ssh/config` file.  Please consult your ssh documentation
 578for further details.
 579
 580'GIT_FLUSH'::
 581        If this environment variable is set to "1", then commands such
 582        as 'git-blame' (in incremental mode), 'git-rev-list', 'git-log',
 583        and 'git-whatchanged' will force a flush of the output stream
 584        after each commit-oriented record have been flushed.   If this
 585        variable is set to "0", the output of these commands will be done
 586        using completely buffered I/O.   If this environment variable is
 587        not set, git will choose buffered or record-oriented flushing
 588        based on whether stdout appears to be redirected to a file or not.
 589
 590'GIT_TRACE'::
 591        If this variable is set to "1", "2" or "true" (comparison
 592        is case insensitive), git will print `trace:` messages on
 593        stderr telling about alias expansion, built-in command
 594        execution and external command execution.
 595        If this variable is set to an integer value greater than 1
 596        and lower than 10 (strictly) then git will interpret this
 597        value as an open file descriptor and will try to write the
 598        trace messages into this file descriptor.
 599        Alternatively, if this variable is set to an absolute path
 600        (starting with a '/' character), git will interpret this
 601        as a file path and will try to write the trace messages
 602        into it.
 603
 604Discussion[[Discussion]]
 605------------------------
 606
 607More detail on the following is available from the
 608link:user-manual.html#git-concepts[git concepts chapter of the
 609user-manual] and linkgit:gitcore-tutorial[7].
 610
 611A git project normally consists of a working directory with a ".git"
 612subdirectory at the top level.  The .git directory contains, among other
 613things, a compressed object database representing the complete history
 614of the project, an "index" file which links that history to the current
 615contents of the working tree, and named pointers into that history such
 616as tags and branch heads.
 617
 618The object database contains objects of three main types: blobs, which
 619hold file data; trees, which point to blobs and other trees to build up
 620directory hierarchies; and commits, which each reference a single tree
 621and some number of parent commits.
 622
 623The commit, equivalent to what other systems call a "changeset" or
 624"version", represents a step in the project's history, and each parent
 625represents an immediately preceding step.  Commits with more than one
 626parent represent merges of independent lines of development.
 627
 628All objects are named by the SHA1 hash of their contents, normally
 629written as a string of 40 hex digits.  Such names are globally unique.
 630The entire history leading up to a commit can be vouched for by signing
 631just that commit.  A fourth object type, the tag, is provided for this
 632purpose.
 633
 634When first created, objects are stored in individual files, but for
 635efficiency may later be compressed together into "pack files".
 636
 637Named pointers called refs mark interesting points in history.  A ref
 638may contain the SHA1 name of an object or the name of another ref.  Refs
 639with names beginning `ref/head/` contain the SHA1 name of the most
 640recent commit (or "head") of a branch under development.  SHA1 names of
 641tags of interest are stored under `ref/tags/`.  A special ref named
 642`HEAD` contains the name of the currently checked-out branch.
 643
 644The index file is initialized with a list of all paths and, for each
 645path, a blob object and a set of attributes.  The blob object represents
 646the contents of the file as of the head of the current branch.  The
 647attributes (last modified time, size, etc.) are taken from the
 648corresponding file in the working tree.  Subsequent changes to the
 649working tree can be found by comparing these attributes.  The index may
 650be updated with new content, and new commits may be created from the
 651content stored in the index.
 652
 653The index is also capable of storing multiple entries (called "stages")
 654for a given pathname.  These stages are used to hold the various
 655unmerged version of a file when a merge is in progress.
 656
 657Authors
 658-------
 659* git's founding father is Linus Torvalds <torvalds@osdl.org>.
 660* The current git nurse is Junio C Hamano <gitster@pobox.com>.
 661* The git potty was written by Andreas Ericsson <ae@op5.se>.
 662* General upbringing is handled by the git-list <git@vger.kernel.org>.
 663
 664Documentation
 665--------------
 666The documentation for git suite was started by David Greaves
 667<david@dgreaves.com>, and later enhanced greatly by the
 668contributors on the git-list <git@vger.kernel.org>.
 669
 670SEE ALSO
 671--------
 672linkgit:gittutorial[7], linkgit:gittutorial-2[7],
 673link:everyday.html[Everyday Git], linkgit:gitcvs-migration[7],
 674linkgit:gitglossary[7], linkgit:gitcore-tutorial[7],
 675linkgit:gitcli[7], link:user-manual.html[The Git User's Manual],
 676linkgit:gitworkflows[7]
 677
 678GIT
 679---
 680Part of the linkgit:git[1] suite