Documentation / git.txton commit Merge branch 'rc/maint-reflog-msg-for-forced-branch' into maint (c512b03)
   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:v1.7.0.4/git.html[documentation for release 1.7.0.4]
  47
  48* release notes for
  49  link:RelNotes-1.7.0.4.txt[1.7.0.4],
  50  link:RelNotes-1.7.0.3.txt[1.7.0.3],
  51  link:RelNotes-1.7.0.2.txt[1.7.0.2],
  52  link:RelNotes-1.7.0.1.txt[1.7.0.1],
  53  link:RelNotes-1.7.0.txt[1.7.0].
  54
  55* link:v1.6.6.2/git.html[documentation for release 1.6.6.2]
  56
  57* release notes for
  58  link:RelNotes-1.6.6.2.txt[1.6.6.2],
  59  link:RelNotes-1.6.6.1.txt[1.6.6.1],
  60  link:RelNotes-1.6.6.txt[1.6.6].
  61
  62* link:v1.6.5.8/git.html[documentation for release 1.6.5.8]
  63
  64* release notes for
  65  link:RelNotes-1.6.5.8.txt[1.6.5.8],
  66  link:RelNotes-1.6.5.7.txt[1.6.5.7],
  67  link:RelNotes-1.6.5.6.txt[1.6.5.6],
  68  link:RelNotes-1.6.5.5.txt[1.6.5.5],
  69  link:RelNotes-1.6.5.4.txt[1.6.5.4],
  70  link:RelNotes-1.6.5.3.txt[1.6.5.3],
  71  link:RelNotes-1.6.5.2.txt[1.6.5.2],
  72  link:RelNotes-1.6.5.1.txt[1.6.5.1],
  73  link:RelNotes-1.6.5.txt[1.6.5].
  74
  75* link:v1.6.4.4/git.html[documentation for release 1.6.4.4]
  76
  77* release notes for
  78  link:RelNotes-1.6.4.4.txt[1.6.4.4],
  79  link:RelNotes-1.6.4.3.txt[1.6.4.3],
  80  link:RelNotes-1.6.4.2.txt[1.6.4.2],
  81  link:RelNotes-1.6.4.1.txt[1.6.4.1],
  82  link:RelNotes-1.6.4.txt[1.6.4].
  83
  84* link:v1.6.3.4/git.html[documentation for release 1.6.3.4]
  85
  86* release notes for
  87  link:RelNotes-1.6.3.4.txt[1.6.3.4],
  88  link:RelNotes-1.6.3.3.txt[1.6.3.3],
  89  link:RelNotes-1.6.3.2.txt[1.6.3.2],
  90  link:RelNotes-1.6.3.1.txt[1.6.3.1],
  91  link:RelNotes-1.6.3.txt[1.6.3].
  92
  93* release notes for
  94  link:RelNotes-1.6.2.5.txt[1.6.2.5],
  95  link:RelNotes-1.6.2.4.txt[1.6.2.4],
  96  link:RelNotes-1.6.2.3.txt[1.6.2.3],
  97  link:RelNotes-1.6.2.2.txt[1.6.2.2],
  98  link:RelNotes-1.6.2.1.txt[1.6.2.1],
  99  link:RelNotes-1.6.2.txt[1.6.2].
 100
 101* link:v1.6.1.3/git.html[documentation for release 1.6.1.3]
 102
 103* release notes for
 104  link:RelNotes-1.6.1.3.txt[1.6.1.3],
 105  link:RelNotes-1.6.1.2.txt[1.6.1.2],
 106  link:RelNotes-1.6.1.1.txt[1.6.1.1],
 107  link:RelNotes-1.6.1.txt[1.6.1].
 108
 109* link:v1.6.0.6/git.html[documentation for release 1.6.0.6]
 110
 111* release notes for
 112  link:RelNotes-1.6.0.6.txt[1.6.0.6],
 113  link:RelNotes-1.6.0.5.txt[1.6.0.5],
 114  link:RelNotes-1.6.0.4.txt[1.6.0.4],
 115  link:RelNotes-1.6.0.3.txt[1.6.0.3],
 116  link:RelNotes-1.6.0.2.txt[1.6.0.2],
 117  link:RelNotes-1.6.0.1.txt[1.6.0.1],
 118  link:RelNotes-1.6.0.txt[1.6.0].
 119
 120* link:v1.5.6.6/git.html[documentation for release 1.5.6.6]
 121
 122* release notes for
 123  link:RelNotes-1.5.6.6.txt[1.5.6.6],
 124  link:RelNotes-1.5.6.5.txt[1.5.6.5],
 125  link:RelNotes-1.5.6.4.txt[1.5.6.4],
 126  link:RelNotes-1.5.6.3.txt[1.5.6.3],
 127  link:RelNotes-1.5.6.2.txt[1.5.6.2],
 128  link:RelNotes-1.5.6.1.txt[1.5.6.1],
 129  link:RelNotes-1.5.6.txt[1.5.6].
 130
 131* link:v1.5.5.6/git.html[documentation for release 1.5.5.6]
 132
 133* release notes for
 134  link:RelNotes-1.5.5.6.txt[1.5.5.6],
 135  link:RelNotes-1.5.5.5.txt[1.5.5.5],
 136  link:RelNotes-1.5.5.4.txt[1.5.5.4],
 137  link:RelNotes-1.5.5.3.txt[1.5.5.3],
 138  link:RelNotes-1.5.5.2.txt[1.5.5.2],
 139  link:RelNotes-1.5.5.1.txt[1.5.5.1],
 140  link:RelNotes-1.5.5.txt[1.5.5].
 141
 142* link:v1.5.4.7/git.html[documentation for release 1.5.4.7]
 143
 144* release notes for
 145  link:RelNotes-1.5.4.7.txt[1.5.4.7],
 146  link:RelNotes-1.5.4.6.txt[1.5.4.6],
 147  link:RelNotes-1.5.4.5.txt[1.5.4.5],
 148  link:RelNotes-1.5.4.4.txt[1.5.4.4],
 149  link:RelNotes-1.5.4.3.txt[1.5.4.3],
 150  link:RelNotes-1.5.4.2.txt[1.5.4.2],
 151  link:RelNotes-1.5.4.1.txt[1.5.4.1],
 152  link:RelNotes-1.5.4.txt[1.5.4].
 153
 154* link:v1.5.3.8/git.html[documentation for release 1.5.3.8]
 155
 156* release notes for
 157  link:RelNotes-1.5.3.8.txt[1.5.3.8],
 158  link:RelNotes-1.5.3.7.txt[1.5.3.7],
 159  link:RelNotes-1.5.3.6.txt[1.5.3.6],
 160  link:RelNotes-1.5.3.5.txt[1.5.3.5],
 161  link:RelNotes-1.5.3.4.txt[1.5.3.4],
 162  link:RelNotes-1.5.3.3.txt[1.5.3.3],
 163  link:RelNotes-1.5.3.2.txt[1.5.3.2],
 164  link:RelNotes-1.5.3.1.txt[1.5.3.1],
 165  link:RelNotes-1.5.3.txt[1.5.3].
 166
 167* link:v1.5.2.5/git.html[documentation for release 1.5.2.5]
 168
 169* release notes for
 170  link:RelNotes-1.5.2.5.txt[1.5.2.5],
 171  link:RelNotes-1.5.2.4.txt[1.5.2.4],
 172  link:RelNotes-1.5.2.3.txt[1.5.2.3],
 173  link:RelNotes-1.5.2.2.txt[1.5.2.2],
 174  link:RelNotes-1.5.2.1.txt[1.5.2.1],
 175  link:RelNotes-1.5.2.txt[1.5.2].
 176
 177* link:v1.5.1.6/git.html[documentation for release 1.5.1.6]
 178
 179* release notes for
 180  link:RelNotes-1.5.1.6.txt[1.5.1.6],
 181  link:RelNotes-1.5.1.5.txt[1.5.1.5],
 182  link:RelNotes-1.5.1.4.txt[1.5.1.4],
 183  link:RelNotes-1.5.1.3.txt[1.5.1.3],
 184  link:RelNotes-1.5.1.2.txt[1.5.1.2],
 185  link:RelNotes-1.5.1.1.txt[1.5.1.1],
 186  link:RelNotes-1.5.1.txt[1.5.1].
 187
 188* link:v1.5.0.7/git.html[documentation for release 1.5.0.7]
 189
 190* release notes for
 191  link:RelNotes-1.5.0.7.txt[1.5.0.7],
 192  link:RelNotes-1.5.0.6.txt[1.5.0.6],
 193  link:RelNotes-1.5.0.5.txt[1.5.0.5],
 194  link:RelNotes-1.5.0.3.txt[1.5.0.3],
 195  link:RelNotes-1.5.0.2.txt[1.5.0.2],
 196  link:RelNotes-1.5.0.1.txt[1.5.0.1],
 197  link:RelNotes-1.5.0.txt[1.5.0].
 198
 199* documentation for release link:v1.4.4.4/git.html[1.4.4.4],
 200  link:v1.3.3/git.html[1.3.3],
 201  link:v1.2.6/git.html[1.2.6],
 202  link:v1.0.13/git.html[1.0.13].
 203
 204============
 205
 206endif::stalenotes[]
 207
 208OPTIONS
 209-------
 210--version::
 211        Prints the git suite version that the 'git' program came from.
 212
 213--help::
 214        Prints the synopsis and a list of the most commonly used
 215        commands. If the option '--all' or '-a' is given then all
 216        available commands are printed. If a git command is named this
 217        option will bring up the manual page for that command.
 218+
 219Other options are available to control how the manual page is
 220displayed. See linkgit:git-help[1] for more information,
 221because `git --help ...` is converted internally into `git
 222help ...`.
 223
 224--exec-path::
 225        Path to wherever your core git programs are installed.
 226        This can also be controlled by setting the GIT_EXEC_PATH
 227        environment variable. If no path is given, 'git' will print
 228        the current setting and then exit.
 229
 230--html-path::
 231        Print the path to wherever your git HTML documentation is installed
 232        and exit.
 233
 234-p::
 235--paginate::
 236        Pipe all output into 'less' (or if set, $PAGER) if standard
 237        output is a terminal.  This overrides the `pager.<cmd>`
 238        configuration options (see the "Configuration Mechanism" section
 239        below).
 240
 241--no-pager::
 242        Do not pipe git output into a pager.
 243
 244--git-dir=<path>::
 245        Set the path to the repository. This can also be controlled by
 246        setting the GIT_DIR environment variable. It can be an absolute
 247        path or relative path to current working directory.
 248
 249--work-tree=<path>::
 250        Set the path to the working tree.  The value will not be
 251        used in combination with repositories found automatically in
 252        a .git directory (i.e. $GIT_DIR is not set).
 253        This can also be controlled by setting the GIT_WORK_TREE
 254        environment variable and the core.worktree configuration
 255        variable. It can be an absolute path or relative path to
 256        the directory specified by --git-dir or GIT_DIR.
 257        Note: If --git-dir or GIT_DIR are specified but none of
 258        --work-tree, GIT_WORK_TREE and core.worktree is specified,
 259        the current working directory is regarded as the top directory
 260        of your working tree.
 261
 262--bare::
 263        Treat the repository as a bare repository.  If GIT_DIR
 264        environment is not set, it is set to the current working
 265        directory.
 266
 267--no-replace-objects::
 268        Do not use replacement refs to replace git objects. See
 269        linkgit:git-replace[1] for more information.
 270
 271
 272FURTHER DOCUMENTATION
 273---------------------
 274
 275See the references above to get started using git.  The following is
 276probably more detail than necessary for a first-time user.
 277
 278The link:user-manual.html#git-concepts[git concepts chapter of the
 279user-manual] and linkgit:gitcore-tutorial[7] both provide
 280introductions to the underlying git architecture.
 281
 282See linkgit:gitworkflows[7] for an overview of recommended workflows.
 283
 284See also the link:howto-index.html[howto] documents for some useful
 285examples.
 286
 287The internals are documented in the
 288link:technical/api-index.html[GIT API documentation].
 289
 290GIT COMMANDS
 291------------
 292
 293We divide git into high level ("porcelain") commands and low level
 294("plumbing") commands.
 295
 296High-level commands (porcelain)
 297-------------------------------
 298
 299We separate the porcelain commands into the main commands and some
 300ancillary user utilities.
 301
 302Main porcelain commands
 303~~~~~~~~~~~~~~~~~~~~~~~
 304
 305include::cmds-mainporcelain.txt[]
 306
 307Ancillary Commands
 308~~~~~~~~~~~~~~~~~~
 309Manipulators:
 310
 311include::cmds-ancillarymanipulators.txt[]
 312
 313Interrogators:
 314
 315include::cmds-ancillaryinterrogators.txt[]
 316
 317
 318Interacting with Others
 319~~~~~~~~~~~~~~~~~~~~~~~
 320
 321These commands are to interact with foreign SCM and with other
 322people via patch over e-mail.
 323
 324include::cmds-foreignscminterface.txt[]
 325
 326
 327Low-level commands (plumbing)
 328-----------------------------
 329
 330Although git includes its
 331own porcelain layer, its low-level commands are sufficient to support
 332development of alternative porcelains.  Developers of such porcelains
 333might start by reading about linkgit:git-update-index[1] and
 334linkgit:git-read-tree[1].
 335
 336The interface (input, output, set of options and the semantics)
 337to these low-level commands are meant to be a lot more stable
 338than Porcelain level commands, because these commands are
 339primarily for scripted use.  The interface to Porcelain commands
 340on the other hand are subject to change in order to improve the
 341end user experience.
 342
 343The following description divides
 344the low-level commands into commands that manipulate objects (in
 345the repository, index, and working tree), commands that interrogate and
 346compare objects, and commands that move objects and references between
 347repositories.
 348
 349
 350Manipulation commands
 351~~~~~~~~~~~~~~~~~~~~~
 352
 353include::cmds-plumbingmanipulators.txt[]
 354
 355
 356Interrogation commands
 357~~~~~~~~~~~~~~~~~~~~~~
 358
 359include::cmds-plumbinginterrogators.txt[]
 360
 361In general, the interrogate commands do not touch the files in
 362the working tree.
 363
 364
 365Synching repositories
 366~~~~~~~~~~~~~~~~~~~~~
 367
 368include::cmds-synchingrepositories.txt[]
 369
 370The following are helper commands used by the above; end users
 371typically do not use them directly.
 372
 373include::cmds-synchelpers.txt[]
 374
 375
 376Internal helper commands
 377~~~~~~~~~~~~~~~~~~~~~~~~
 378
 379These are internal helper commands used by other commands; end
 380users typically do not use them directly.
 381
 382include::cmds-purehelpers.txt[]
 383
 384
 385Configuration Mechanism
 386-----------------------
 387
 388Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file
 389is used to hold per-repository configuration options.  It is a
 390simple text file modeled after `.ini` format familiar to some
 391people.  Here is an example:
 392
 393------------
 394#
 395# A '#' or ';' character indicates a comment.
 396#
 397
 398; core variables
 399[core]
 400        ; Don't trust file modes
 401        filemode = false
 402
 403; user identity
 404[user]
 405        name = "Junio C Hamano"
 406        email = "junkio@twinsun.com"
 407
 408------------
 409
 410Various commands read from the configuration file and adjust
 411their operation accordingly.  See linkgit:git-config[1] for a
 412list.
 413
 414
 415Identifier Terminology
 416----------------------
 417<object>::
 418        Indicates the object name for any type of object.
 419
 420<blob>::
 421        Indicates a blob object name.
 422
 423<tree>::
 424        Indicates a tree object name.
 425
 426<commit>::
 427        Indicates a commit object name.
 428
 429<tree-ish>::
 430        Indicates a tree, commit or tag object name.  A
 431        command that takes a <tree-ish> argument ultimately wants to
 432        operate on a <tree> object but automatically dereferences
 433        <commit> and <tag> objects that point at a <tree>.
 434
 435<commit-ish>::
 436        Indicates a commit or tag object name.  A
 437        command that takes a <commit-ish> argument ultimately wants to
 438        operate on a <commit> object but automatically dereferences
 439        <tag> objects that point at a <commit>.
 440
 441<type>::
 442        Indicates that an object type is required.
 443        Currently one of: `blob`, `tree`, `commit`, or `tag`.
 444
 445<file>::
 446        Indicates a filename - almost always relative to the
 447        root of the tree structure `GIT_INDEX_FILE` describes.
 448
 449Symbolic Identifiers
 450--------------------
 451Any git command accepting any <object> can also use the following
 452symbolic notation:
 453
 454HEAD::
 455        indicates the head of the current branch (i.e. the
 456        contents of `$GIT_DIR/HEAD`).
 457
 458<tag>::
 459        a valid tag 'name'
 460        (i.e. the contents of `$GIT_DIR/refs/tags/<tag>`).
 461
 462<head>::
 463        a valid head 'name'
 464        (i.e. the contents of `$GIT_DIR/refs/heads/<head>`).
 465
 466For a more complete list of ways to spell object names, see
 467"SPECIFYING REVISIONS" section in linkgit:git-rev-parse[1].
 468
 469
 470File/Directory Structure
 471------------------------
 472
 473Please see the linkgit:gitrepository-layout[5] document.
 474
 475Read linkgit:githooks[5] for more details about each hook.
 476
 477Higher level SCMs may provide and manage additional information in the
 478`$GIT_DIR`.
 479
 480
 481Terminology
 482-----------
 483Please see linkgit:gitglossary[7].
 484
 485
 486Environment Variables
 487---------------------
 488Various git commands use the following environment variables:
 489
 490The git Repository
 491~~~~~~~~~~~~~~~~~~
 492These environment variables apply to 'all' core git commands. Nb: it
 493is worth noting that they may be used/overridden by SCMS sitting above
 494git so take care if using Cogito etc.
 495
 496'GIT_INDEX_FILE'::
 497        This environment allows the specification of an alternate
 498        index file. If not specified, the default of `$GIT_DIR/index`
 499        is used.
 500
 501'GIT_OBJECT_DIRECTORY'::
 502        If the object storage directory is specified via this
 503        environment variable then the sha1 directories are created
 504        underneath - otherwise the default `$GIT_DIR/objects`
 505        directory is used.
 506
 507'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
 508        Due to the immutable nature of git objects, old objects can be
 509        archived into shared, read-only directories. This variable
 510        specifies a ":" separated (on Windows ";" separated) list
 511        of git object directories which can be used to search for git
 512        objects. New objects will not be written to these directories.
 513
 514'GIT_DIR'::
 515        If the 'GIT_DIR' environment variable is set then it
 516        specifies a path to use instead of the default `.git`
 517        for the base of the repository.
 518
 519'GIT_WORK_TREE'::
 520        Set the path to the working tree.  The value will not be
 521        used in combination with repositories found automatically in
 522        a .git directory (i.e. $GIT_DIR is not set).
 523        This can also be controlled by the '--work-tree' command line
 524        option and the core.worktree configuration variable.
 525
 526'GIT_CEILING_DIRECTORIES'::
 527        This should be a colon-separated list of absolute paths.
 528        If set, it is a list of directories that git should not chdir
 529        up into while looking for a repository directory.
 530        It will not exclude the current working directory or
 531        a GIT_DIR set on the command line or in the environment.
 532        (Useful for excluding slow-loading network directories.)
 533
 534git Commits
 535~~~~~~~~~~~
 536'GIT_AUTHOR_NAME'::
 537'GIT_AUTHOR_EMAIL'::
 538'GIT_AUTHOR_DATE'::
 539'GIT_COMMITTER_NAME'::
 540'GIT_COMMITTER_EMAIL'::
 541'GIT_COMMITTER_DATE'::
 542'EMAIL'::
 543        see linkgit:git-commit-tree[1]
 544
 545git Diffs
 546~~~~~~~~~
 547'GIT_DIFF_OPTS'::
 548        Only valid setting is "--unified=??" or "-u??" to set the
 549        number of context lines shown when a unified diff is created.
 550        This takes precedence over any "-U" or "--unified" option
 551        value passed on the git diff command line.
 552
 553'GIT_EXTERNAL_DIFF'::
 554        When the environment variable 'GIT_EXTERNAL_DIFF' is set, the
 555        program named by it is called, instead of the diff invocation
 556        described above.  For a path that is added, removed, or modified,
 557        'GIT_EXTERNAL_DIFF' is called with 7 parameters:
 558
 559        path old-file old-hex old-mode new-file new-hex new-mode
 560+
 561where:
 562
 563        <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the
 564                         contents of <old|new>,
 565        <old|new>-hex:: are the 40-hexdigit SHA1 hashes,
 566        <old|new>-mode:: are the octal representation of the file modes.
 567
 568+
 569The file parameters can point at the user's working file
 570(e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
 571when a new file is added), or a temporary file (e.g. `old-file` in the
 572index).  'GIT_EXTERNAL_DIFF' should not worry about unlinking the
 573temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits.
 574+
 575For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1
 576parameter, <path>.
 577
 578other
 579~~~~~
 580'GIT_MERGE_VERBOSITY'::
 581        A number controlling the amount of output shown by
 582        the recursive merge strategy.  Overrides merge.verbosity.
 583        See linkgit:git-merge[1]
 584
 585'GIT_PAGER'::
 586        This environment variable overrides `$PAGER`. If it is set
 587        to an empty string or to the value "cat", git will not launch
 588        a pager.  See also the `core.pager` option in
 589        linkgit:git-config[1].
 590
 591'GIT_SSH'::
 592        If this environment variable is set then 'git fetch'
 593        and 'git push' will use this command instead
 594        of 'ssh' when they need to connect to a remote system.
 595        The '$GIT_SSH' command will be given exactly two arguments:
 596        the 'username@host' (or just 'host') from the URL and the
 597        shell command to execute on that remote system.
 598+
 599To pass options to the program that you want to list in GIT_SSH
 600you will need to wrap the program and options into a shell script,
 601then set GIT_SSH to refer to the shell script.
 602+
 603Usually it is easier to configure any desired options through your
 604personal `.ssh/config` file.  Please consult your ssh documentation
 605for further details.
 606
 607'GIT_FLUSH'::
 608        If this environment variable is set to "1", then commands such
 609        as 'git blame' (in incremental mode), 'git rev-list', 'git log',
 610        and 'git whatchanged' will force a flush of the output stream
 611        after each commit-oriented record have been flushed.   If this
 612        variable is set to "0", the output of these commands will be done
 613        using completely buffered I/O.   If this environment variable is
 614        not set, git will choose buffered or record-oriented flushing
 615        based on whether stdout appears to be redirected to a file or not.
 616
 617'GIT_TRACE'::
 618        If this variable is set to "1", "2" or "true" (comparison
 619        is case insensitive), git will print `trace:` messages on
 620        stderr telling about alias expansion, built-in command
 621        execution and external command execution.
 622        If this variable is set to an integer value greater than 1
 623        and lower than 10 (strictly) then git will interpret this
 624        value as an open file descriptor and will try to write the
 625        trace messages into this file descriptor.
 626        Alternatively, if this variable is set to an absolute path
 627        (starting with a '/' character), git will interpret this
 628        as a file path and will try to write the trace messages
 629        into it.
 630
 631Discussion[[Discussion]]
 632------------------------
 633
 634More detail on the following is available from the
 635link:user-manual.html#git-concepts[git concepts chapter of the
 636user-manual] and linkgit:gitcore-tutorial[7].
 637
 638A git project normally consists of a working directory with a ".git"
 639subdirectory at the top level.  The .git directory contains, among other
 640things, a compressed object database representing the complete history
 641of the project, an "index" file which links that history to the current
 642contents of the working tree, and named pointers into that history such
 643as tags and branch heads.
 644
 645The object database contains objects of three main types: blobs, which
 646hold file data; trees, which point to blobs and other trees to build up
 647directory hierarchies; and commits, which each reference a single tree
 648and some number of parent commits.
 649
 650The commit, equivalent to what other systems call a "changeset" or
 651"version", represents a step in the project's history, and each parent
 652represents an immediately preceding step.  Commits with more than one
 653parent represent merges of independent lines of development.
 654
 655All objects are named by the SHA1 hash of their contents, normally
 656written as a string of 40 hex digits.  Such names are globally unique.
 657The entire history leading up to a commit can be vouched for by signing
 658just that commit.  A fourth object type, the tag, is provided for this
 659purpose.
 660
 661When first created, objects are stored in individual files, but for
 662efficiency may later be compressed together into "pack files".
 663
 664Named pointers called refs mark interesting points in history.  A ref
 665may contain the SHA1 name of an object or the name of another ref.  Refs
 666with names beginning `ref/head/` contain the SHA1 name of the most
 667recent commit (or "head") of a branch under development.  SHA1 names of
 668tags of interest are stored under `ref/tags/`.  A special ref named
 669`HEAD` contains the name of the currently checked-out branch.
 670
 671The index file is initialized with a list of all paths and, for each
 672path, a blob object and a set of attributes.  The blob object represents
 673the contents of the file as of the head of the current branch.  The
 674attributes (last modified time, size, etc.) are taken from the
 675corresponding file in the working tree.  Subsequent changes to the
 676working tree can be found by comparing these attributes.  The index may
 677be updated with new content, and new commits may be created from the
 678content stored in the index.
 679
 680The index is also capable of storing multiple entries (called "stages")
 681for a given pathname.  These stages are used to hold the various
 682unmerged version of a file when a merge is in progress.
 683
 684Authors
 685-------
 686* git's founding father is Linus Torvalds <torvalds@osdl.org>.
 687* The current git nurse is Junio C Hamano <gitster@pobox.com>.
 688* The git potty was written by Andreas Ericsson <ae@op5.se>.
 689* General upbringing is handled by the git-list <git@vger.kernel.org>.
 690
 691Documentation
 692--------------
 693The documentation for git suite was started by David Greaves
 694<david@dgreaves.com>, and later enhanced greatly by the
 695contributors on the git-list <git@vger.kernel.org>.
 696
 697SEE ALSO
 698--------
 699linkgit:gittutorial[7], linkgit:gittutorial-2[7],
 700link:everyday.html[Everyday Git], linkgit:gitcvs-migration[7],
 701linkgit:gitglossary[7], linkgit:gitcore-tutorial[7],
 702linkgit:gitcli[7], link:user-manual.html[The Git User's Manual],
 703linkgit:gitworkflows[7]
 704
 705GIT
 706---
 707Part of the linkgit:git[1] suite