Documentation / git.txton commit Add the 'diff.ignoreSubmodules' config setting (be4f2b4)
   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    [-c name=value]
  16    [--help] COMMAND [ARGS]
  17
  18DESCRIPTION
  19-----------
  20Git is a fast, scalable, distributed revision control system with an
  21unusually rich command set that provides both high-level operations
  22and full access to internals.
  23
  24See linkgit:gittutorial[7] to get started, then see
  25link:everyday.html[Everyday Git] for a useful minimum set of commands, and
  26"man git-commandname" for documentation of each command.  CVS users may
  27also want to read linkgit:gitcvs-migration[7].  See
  28the link:user-manual.html[Git User's Manual] for a more in-depth
  29introduction.
  30
  31The COMMAND is either a name of a Git command (see below) or an alias
  32as defined in the configuration file (see linkgit:git-config[1]).
  33
  34Formatted and hyperlinked version of the latest git
  35documentation can be viewed at
  36`http://www.kernel.org/pub/software/scm/git/docs/`.
  37
  38ifdef::stalenotes[]
  39[NOTE]
  40============
  41
  42You are reading the documentation for the latest (possibly
  43unreleased) version of git, that is available from 'master'
  44branch of the `git.git` repository.
  45Documentation for older releases are available here:
  46
  47* link:v1.7.2/git.html[documentation for release 1.7.2]
  48
  49* release notes for
  50  link:RelNotes-1.7.2.txt[1.7.2].
  51
  52* link:v1.7.1.1/git.html[documentation for release 1.7.1.1]
  53
  54* release notes for
  55  link:RelNotes-1.7.1.1.txt[1.7.1.1],
  56  link:RelNotes-1.7.1.txt[1.7.1].
  57
  58* link:v1.7.0.6/git.html[documentation for release 1.7.0.6]
  59
  60* release notes for
  61  link:RelNotes-1.7.0.6.txt[1.7.0.6],
  62  link:RelNotes-1.7.0.5.txt[1.7.0.5],
  63  link:RelNotes-1.7.0.4.txt[1.7.0.4],
  64  link:RelNotes-1.7.0.3.txt[1.7.0.3],
  65  link:RelNotes-1.7.0.2.txt[1.7.0.2],
  66  link:RelNotes-1.7.0.1.txt[1.7.0.1],
  67  link:RelNotes-1.7.0.txt[1.7.0].
  68
  69* link:v1.6.6.2/git.html[documentation for release 1.6.6.2]
  70
  71* release notes for
  72  link:RelNotes-1.6.6.2.txt[1.6.6.2],
  73  link:RelNotes-1.6.6.1.txt[1.6.6.1],
  74  link:RelNotes-1.6.6.txt[1.6.6].
  75
  76* link:v1.6.5.8/git.html[documentation for release 1.6.5.8]
  77
  78* release notes for
  79  link:RelNotes-1.6.5.8.txt[1.6.5.8],
  80  link:RelNotes-1.6.5.7.txt[1.6.5.7],
  81  link:RelNotes-1.6.5.6.txt[1.6.5.6],
  82  link:RelNotes-1.6.5.5.txt[1.6.5.5],
  83  link:RelNotes-1.6.5.4.txt[1.6.5.4],
  84  link:RelNotes-1.6.5.3.txt[1.6.5.3],
  85  link:RelNotes-1.6.5.2.txt[1.6.5.2],
  86  link:RelNotes-1.6.5.1.txt[1.6.5.1],
  87  link:RelNotes-1.6.5.txt[1.6.5].
  88
  89* link:v1.6.4.4/git.html[documentation for release 1.6.4.4]
  90
  91* release notes for
  92  link:RelNotes-1.6.4.4.txt[1.6.4.4],
  93  link:RelNotes-1.6.4.3.txt[1.6.4.3],
  94  link:RelNotes-1.6.4.2.txt[1.6.4.2],
  95  link:RelNotes-1.6.4.1.txt[1.6.4.1],
  96  link:RelNotes-1.6.4.txt[1.6.4].
  97
  98* link:v1.6.3.4/git.html[documentation for release 1.6.3.4]
  99
 100* release notes for
 101  link:RelNotes-1.6.3.4.txt[1.6.3.4],
 102  link:RelNotes-1.6.3.3.txt[1.6.3.3],
 103  link:RelNotes-1.6.3.2.txt[1.6.3.2],
 104  link:RelNotes-1.6.3.1.txt[1.6.3.1],
 105  link:RelNotes-1.6.3.txt[1.6.3].
 106
 107* release notes for
 108  link:RelNotes-1.6.2.5.txt[1.6.2.5],
 109  link:RelNotes-1.6.2.4.txt[1.6.2.4],
 110  link:RelNotes-1.6.2.3.txt[1.6.2.3],
 111  link:RelNotes-1.6.2.2.txt[1.6.2.2],
 112  link:RelNotes-1.6.2.1.txt[1.6.2.1],
 113  link:RelNotes-1.6.2.txt[1.6.2].
 114
 115* link:v1.6.1.3/git.html[documentation for release 1.6.1.3]
 116
 117* release notes for
 118  link:RelNotes-1.6.1.3.txt[1.6.1.3],
 119  link:RelNotes-1.6.1.2.txt[1.6.1.2],
 120  link:RelNotes-1.6.1.1.txt[1.6.1.1],
 121  link:RelNotes-1.6.1.txt[1.6.1].
 122
 123* link:v1.6.0.6/git.html[documentation for release 1.6.0.6]
 124
 125* release notes for
 126  link:RelNotes-1.6.0.6.txt[1.6.0.6],
 127  link:RelNotes-1.6.0.5.txt[1.6.0.5],
 128  link:RelNotes-1.6.0.4.txt[1.6.0.4],
 129  link:RelNotes-1.6.0.3.txt[1.6.0.3],
 130  link:RelNotes-1.6.0.2.txt[1.6.0.2],
 131  link:RelNotes-1.6.0.1.txt[1.6.0.1],
 132  link:RelNotes-1.6.0.txt[1.6.0].
 133
 134* link:v1.5.6.6/git.html[documentation for release 1.5.6.6]
 135
 136* release notes for
 137  link:RelNotes-1.5.6.6.txt[1.5.6.6],
 138  link:RelNotes-1.5.6.5.txt[1.5.6.5],
 139  link:RelNotes-1.5.6.4.txt[1.5.6.4],
 140  link:RelNotes-1.5.6.3.txt[1.5.6.3],
 141  link:RelNotes-1.5.6.2.txt[1.5.6.2],
 142  link:RelNotes-1.5.6.1.txt[1.5.6.1],
 143  link:RelNotes-1.5.6.txt[1.5.6].
 144
 145* link:v1.5.5.6/git.html[documentation for release 1.5.5.6]
 146
 147* release notes for
 148  link:RelNotes-1.5.5.6.txt[1.5.5.6],
 149  link:RelNotes-1.5.5.5.txt[1.5.5.5],
 150  link:RelNotes-1.5.5.4.txt[1.5.5.4],
 151  link:RelNotes-1.5.5.3.txt[1.5.5.3],
 152  link:RelNotes-1.5.5.2.txt[1.5.5.2],
 153  link:RelNotes-1.5.5.1.txt[1.5.5.1],
 154  link:RelNotes-1.5.5.txt[1.5.5].
 155
 156* link:v1.5.4.7/git.html[documentation for release 1.5.4.7]
 157
 158* release notes for
 159  link:RelNotes-1.5.4.7.txt[1.5.4.7],
 160  link:RelNotes-1.5.4.6.txt[1.5.4.6],
 161  link:RelNotes-1.5.4.5.txt[1.5.4.5],
 162  link:RelNotes-1.5.4.4.txt[1.5.4.4],
 163  link:RelNotes-1.5.4.3.txt[1.5.4.3],
 164  link:RelNotes-1.5.4.2.txt[1.5.4.2],
 165  link:RelNotes-1.5.4.1.txt[1.5.4.1],
 166  link:RelNotes-1.5.4.txt[1.5.4].
 167
 168* link:v1.5.3.8/git.html[documentation for release 1.5.3.8]
 169
 170* release notes for
 171  link:RelNotes-1.5.3.8.txt[1.5.3.8],
 172  link:RelNotes-1.5.3.7.txt[1.5.3.7],
 173  link:RelNotes-1.5.3.6.txt[1.5.3.6],
 174  link:RelNotes-1.5.3.5.txt[1.5.3.5],
 175  link:RelNotes-1.5.3.4.txt[1.5.3.4],
 176  link:RelNotes-1.5.3.3.txt[1.5.3.3],
 177  link:RelNotes-1.5.3.2.txt[1.5.3.2],
 178  link:RelNotes-1.5.3.1.txt[1.5.3.1],
 179  link:RelNotes-1.5.3.txt[1.5.3].
 180
 181* link:v1.5.2.5/git.html[documentation for release 1.5.2.5]
 182
 183* release notes for
 184  link:RelNotes-1.5.2.5.txt[1.5.2.5],
 185  link:RelNotes-1.5.2.4.txt[1.5.2.4],
 186  link:RelNotes-1.5.2.3.txt[1.5.2.3],
 187  link:RelNotes-1.5.2.2.txt[1.5.2.2],
 188  link:RelNotes-1.5.2.1.txt[1.5.2.1],
 189  link:RelNotes-1.5.2.txt[1.5.2].
 190
 191* link:v1.5.1.6/git.html[documentation for release 1.5.1.6]
 192
 193* release notes for
 194  link:RelNotes-1.5.1.6.txt[1.5.1.6],
 195  link:RelNotes-1.5.1.5.txt[1.5.1.5],
 196  link:RelNotes-1.5.1.4.txt[1.5.1.4],
 197  link:RelNotes-1.5.1.3.txt[1.5.1.3],
 198  link:RelNotes-1.5.1.2.txt[1.5.1.2],
 199  link:RelNotes-1.5.1.1.txt[1.5.1.1],
 200  link:RelNotes-1.5.1.txt[1.5.1].
 201
 202* link:v1.5.0.7/git.html[documentation for release 1.5.0.7]
 203
 204* release notes for
 205  link:RelNotes-1.5.0.7.txt[1.5.0.7],
 206  link:RelNotes-1.5.0.6.txt[1.5.0.6],
 207  link:RelNotes-1.5.0.5.txt[1.5.0.5],
 208  link:RelNotes-1.5.0.3.txt[1.5.0.3],
 209  link:RelNotes-1.5.0.2.txt[1.5.0.2],
 210  link:RelNotes-1.5.0.1.txt[1.5.0.1],
 211  link:RelNotes-1.5.0.txt[1.5.0].
 212
 213* documentation for release link:v1.4.4.4/git.html[1.4.4.4],
 214  link:v1.3.3/git.html[1.3.3],
 215  link:v1.2.6/git.html[1.2.6],
 216  link:v1.0.13/git.html[1.0.13].
 217
 218============
 219
 220endif::stalenotes[]
 221
 222OPTIONS
 223-------
 224--version::
 225        Prints the git suite version that the 'git' program came from.
 226
 227--help::
 228        Prints the synopsis and a list of the most commonly used
 229        commands. If the option '--all' or '-a' is given then all
 230        available commands are printed. If a git command is named this
 231        option will bring up the manual page for that command.
 232+
 233Other options are available to control how the manual page is
 234displayed. See linkgit:git-help[1] for more information,
 235because `git --help ...` is converted internally into `git
 236help ...`.
 237
 238-c <name>=<value>::
 239        Pass a configuration parameter to the command. The value
 240        given will override values from configuration files.
 241        The <name> is expected in the same format as listed by
 242        'git config' (subkeys separated by dots).
 243
 244--exec-path::
 245        Path to wherever your core git programs are installed.
 246        This can also be controlled by setting the GIT_EXEC_PATH
 247        environment variable. If no path is given, 'git' will print
 248        the current setting and then exit.
 249
 250--html-path::
 251        Print the path to wherever your git HTML documentation is installed
 252        and exit.
 253
 254-p::
 255--paginate::
 256        Pipe all output into 'less' (or if set, $PAGER) if standard
 257        output is a terminal.  This overrides the `pager.<cmd>`
 258        configuration options (see the "Configuration Mechanism" section
 259        below).
 260
 261--no-pager::
 262        Do not pipe git output into a pager.
 263
 264--git-dir=<path>::
 265        Set the path to the repository. This can also be controlled by
 266        setting the GIT_DIR environment variable. It can be an absolute
 267        path or relative path to current working directory.
 268
 269--work-tree=<path>::
 270        Set the path to the working tree.  The value will not be
 271        used in combination with repositories found automatically in
 272        a .git directory (i.e. $GIT_DIR is not set).
 273        This can also be controlled by setting the GIT_WORK_TREE
 274        environment variable and the core.worktree configuration
 275        variable. It can be an absolute path or relative path to
 276        the directory specified by --git-dir or GIT_DIR.
 277        Note: If --git-dir or GIT_DIR are specified but none of
 278        --work-tree, GIT_WORK_TREE and core.worktree is specified,
 279        the current working directory is regarded as the top directory
 280        of your working tree.
 281
 282--bare::
 283        Treat the repository as a bare repository.  If GIT_DIR
 284        environment is not set, it is set to the current working
 285        directory.
 286
 287--no-replace-objects::
 288        Do not use replacement refs to replace git objects. See
 289        linkgit:git-replace[1] for more information.
 290
 291
 292FURTHER DOCUMENTATION
 293---------------------
 294
 295See the references above to get started using git.  The following is
 296probably more detail than necessary for a first-time user.
 297
 298The link:user-manual.html#git-concepts[git concepts chapter of the
 299user-manual] and linkgit:gitcore-tutorial[7] both provide
 300introductions to the underlying git architecture.
 301
 302See linkgit:gitworkflows[7] for an overview of recommended workflows.
 303
 304See also the link:howto-index.html[howto] documents for some useful
 305examples.
 306
 307The internals are documented in the
 308link:technical/api-index.html[GIT API documentation].
 309
 310GIT COMMANDS
 311------------
 312
 313We divide git into high level ("porcelain") commands and low level
 314("plumbing") commands.
 315
 316High-level commands (porcelain)
 317-------------------------------
 318
 319We separate the porcelain commands into the main commands and some
 320ancillary user utilities.
 321
 322Main porcelain commands
 323~~~~~~~~~~~~~~~~~~~~~~~
 324
 325include::cmds-mainporcelain.txt[]
 326
 327Ancillary Commands
 328~~~~~~~~~~~~~~~~~~
 329Manipulators:
 330
 331include::cmds-ancillarymanipulators.txt[]
 332
 333Interrogators:
 334
 335include::cmds-ancillaryinterrogators.txt[]
 336
 337
 338Interacting with Others
 339~~~~~~~~~~~~~~~~~~~~~~~
 340
 341These commands are to interact with foreign SCM and with other
 342people via patch over e-mail.
 343
 344include::cmds-foreignscminterface.txt[]
 345
 346
 347Low-level commands (plumbing)
 348-----------------------------
 349
 350Although git includes its
 351own porcelain layer, its low-level commands are sufficient to support
 352development of alternative porcelains.  Developers of such porcelains
 353might start by reading about linkgit:git-update-index[1] and
 354linkgit:git-read-tree[1].
 355
 356The interface (input, output, set of options and the semantics)
 357to these low-level commands are meant to be a lot more stable
 358than Porcelain level commands, because these commands are
 359primarily for scripted use.  The interface to Porcelain commands
 360on the other hand are subject to change in order to improve the
 361end user experience.
 362
 363The following description divides
 364the low-level commands into commands that manipulate objects (in
 365the repository, index, and working tree), commands that interrogate and
 366compare objects, and commands that move objects and references between
 367repositories.
 368
 369
 370Manipulation commands
 371~~~~~~~~~~~~~~~~~~~~~
 372
 373include::cmds-plumbingmanipulators.txt[]
 374
 375
 376Interrogation commands
 377~~~~~~~~~~~~~~~~~~~~~~
 378
 379include::cmds-plumbinginterrogators.txt[]
 380
 381In general, the interrogate commands do not touch the files in
 382the working tree.
 383
 384
 385Synching repositories
 386~~~~~~~~~~~~~~~~~~~~~
 387
 388include::cmds-synchingrepositories.txt[]
 389
 390The following are helper commands used by the above; end users
 391typically do not use them directly.
 392
 393include::cmds-synchelpers.txt[]
 394
 395
 396Internal helper commands
 397~~~~~~~~~~~~~~~~~~~~~~~~
 398
 399These are internal helper commands used by other commands; end
 400users typically do not use them directly.
 401
 402include::cmds-purehelpers.txt[]
 403
 404
 405Configuration Mechanism
 406-----------------------
 407
 408Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file
 409is used to hold per-repository configuration options.  It is a
 410simple text file modeled after `.ini` format familiar to some
 411people.  Here is an example:
 412
 413------------
 414#
 415# A '#' or ';' character indicates a comment.
 416#
 417
 418; core variables
 419[core]
 420        ; Don't trust file modes
 421        filemode = false
 422
 423; user identity
 424[user]
 425        name = "Junio C Hamano"
 426        email = "junkio@twinsun.com"
 427
 428------------
 429
 430Various commands read from the configuration file and adjust
 431their operation accordingly.  See linkgit:git-config[1] for a
 432list.
 433
 434
 435Identifier Terminology
 436----------------------
 437<object>::
 438        Indicates the object name for any type of object.
 439
 440<blob>::
 441        Indicates a blob object name.
 442
 443<tree>::
 444        Indicates a tree object name.
 445
 446<commit>::
 447        Indicates a commit object name.
 448
 449<tree-ish>::
 450        Indicates a tree, commit or tag object name.  A
 451        command that takes a <tree-ish> argument ultimately wants to
 452        operate on a <tree> object but automatically dereferences
 453        <commit> and <tag> objects that point at a <tree>.
 454
 455<commit-ish>::
 456        Indicates a commit or tag object name.  A
 457        command that takes a <commit-ish> argument ultimately wants to
 458        operate on a <commit> object but automatically dereferences
 459        <tag> objects that point at a <commit>.
 460
 461<type>::
 462        Indicates that an object type is required.
 463        Currently one of: `blob`, `tree`, `commit`, or `tag`.
 464
 465<file>::
 466        Indicates a filename - almost always relative to the
 467        root of the tree structure `GIT_INDEX_FILE` describes.
 468
 469Symbolic Identifiers
 470--------------------
 471Any git command accepting any <object> can also use the following
 472symbolic notation:
 473
 474HEAD::
 475        indicates the head of the current branch (i.e. the
 476        contents of `$GIT_DIR/HEAD`).
 477
 478<tag>::
 479        a valid tag 'name'
 480        (i.e. the contents of `$GIT_DIR/refs/tags/<tag>`).
 481
 482<head>::
 483        a valid head 'name'
 484        (i.e. the contents of `$GIT_DIR/refs/heads/<head>`).
 485
 486For a more complete list of ways to spell object names, see
 487"SPECIFYING REVISIONS" section in linkgit:gitrevisions[1].
 488
 489
 490File/Directory Structure
 491------------------------
 492
 493Please see the linkgit:gitrepository-layout[5] document.
 494
 495Read linkgit:githooks[5] for more details about each hook.
 496
 497Higher level SCMs may provide and manage additional information in the
 498`$GIT_DIR`.
 499
 500
 501Terminology
 502-----------
 503Please see linkgit:gitglossary[7].
 504
 505
 506Environment Variables
 507---------------------
 508Various git commands use the following environment variables:
 509
 510The git Repository
 511~~~~~~~~~~~~~~~~~~
 512These environment variables apply to 'all' core git commands. Nb: it
 513is worth noting that they may be used/overridden by SCMS sitting above
 514git so take care if using Cogito etc.
 515
 516'GIT_INDEX_FILE'::
 517        This environment allows the specification of an alternate
 518        index file. If not specified, the default of `$GIT_DIR/index`
 519        is used.
 520
 521'GIT_OBJECT_DIRECTORY'::
 522        If the object storage directory is specified via this
 523        environment variable then the sha1 directories are created
 524        underneath - otherwise the default `$GIT_DIR/objects`
 525        directory is used.
 526
 527'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
 528        Due to the immutable nature of git objects, old objects can be
 529        archived into shared, read-only directories. This variable
 530        specifies a ":" separated (on Windows ";" separated) list
 531        of git object directories which can be used to search for git
 532        objects. New objects will not be written to these directories.
 533
 534'GIT_DIR'::
 535        If the 'GIT_DIR' environment variable is set then it
 536        specifies a path to use instead of the default `.git`
 537        for the base of the repository.
 538
 539'GIT_WORK_TREE'::
 540        Set the path to the working tree.  The value will not be
 541        used in combination with repositories found automatically in
 542        a .git directory (i.e. $GIT_DIR is not set).
 543        This can also be controlled by the '--work-tree' command line
 544        option and the core.worktree configuration variable.
 545
 546'GIT_CEILING_DIRECTORIES'::
 547        This should be a colon-separated list of absolute paths.
 548        If set, it is a list of directories that git should not chdir
 549        up into while looking for a repository directory.
 550        It will not exclude the current working directory or
 551        a GIT_DIR set on the command line or in the environment.
 552        (Useful for excluding slow-loading network directories.)
 553
 554'GIT_DISCOVERY_ACROSS_FILESYSTEM'::
 555        When run in a directory that does not have ".git" repository
 556        directory, git tries to find such a directory in the parent
 557        directories to find the top of the working tree, but by default it
 558        does not cross filesystem boundaries.  This environment variable
 559        can be set to true to tell git not to stop at filesystem
 560        boundaries.  Like 'GIT_CEILING_DIRECTORIES', this will not affect
 561        an explicit repository directory set via 'GIT_DIR' or on the
 562        command line.
 563
 564git Commits
 565~~~~~~~~~~~
 566'GIT_AUTHOR_NAME'::
 567'GIT_AUTHOR_EMAIL'::
 568'GIT_AUTHOR_DATE'::
 569'GIT_COMMITTER_NAME'::
 570'GIT_COMMITTER_EMAIL'::
 571'GIT_COMMITTER_DATE'::
 572'EMAIL'::
 573        see linkgit:git-commit-tree[1]
 574
 575git Diffs
 576~~~~~~~~~
 577'GIT_DIFF_OPTS'::
 578        Only valid setting is "--unified=??" or "-u??" to set the
 579        number of context lines shown when a unified diff is created.
 580        This takes precedence over any "-U" or "--unified" option
 581        value passed on the git diff command line.
 582
 583'GIT_EXTERNAL_DIFF'::
 584        When the environment variable 'GIT_EXTERNAL_DIFF' is set, the
 585        program named by it is called, instead of the diff invocation
 586        described above.  For a path that is added, removed, or modified,
 587        'GIT_EXTERNAL_DIFF' is called with 7 parameters:
 588
 589        path old-file old-hex old-mode new-file new-hex new-mode
 590+
 591where:
 592
 593        <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the
 594                         contents of <old|new>,
 595        <old|new>-hex:: are the 40-hexdigit SHA1 hashes,
 596        <old|new>-mode:: are the octal representation of the file modes.
 597
 598+
 599The file parameters can point at the user's working file
 600(e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
 601when a new file is added), or a temporary file (e.g. `old-file` in the
 602index).  'GIT_EXTERNAL_DIFF' should not worry about unlinking the
 603temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits.
 604+
 605For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1
 606parameter, <path>.
 607
 608other
 609~~~~~
 610'GIT_MERGE_VERBOSITY'::
 611        A number controlling the amount of output shown by
 612        the recursive merge strategy.  Overrides merge.verbosity.
 613        See linkgit:git-merge[1]
 614
 615'GIT_PAGER'::
 616        This environment variable overrides `$PAGER`. If it is set
 617        to an empty string or to the value "cat", git will not launch
 618        a pager.  See also the `core.pager` option in
 619        linkgit:git-config[1].
 620
 621'GIT_SSH'::
 622        If this environment variable is set then 'git fetch'
 623        and 'git push' will use this command instead
 624        of 'ssh' when they need to connect to a remote system.
 625        The '$GIT_SSH' command will be given exactly two arguments:
 626        the 'username@host' (or just 'host') from the URL and the
 627        shell command to execute on that remote system.
 628+
 629To pass options to the program that you want to list in GIT_SSH
 630you will need to wrap the program and options into a shell script,
 631then set GIT_SSH to refer to the shell script.
 632+
 633Usually it is easier to configure any desired options through your
 634personal `.ssh/config` file.  Please consult your ssh documentation
 635for further details.
 636
 637'GIT_FLUSH'::
 638        If this environment variable is set to "1", then commands such
 639        as 'git blame' (in incremental mode), 'git rev-list', 'git log',
 640        and 'git whatchanged' will force a flush of the output stream
 641        after each commit-oriented record have been flushed.   If this
 642        variable is set to "0", the output of these commands will be done
 643        using completely buffered I/O.   If this environment variable is
 644        not set, git will choose buffered or record-oriented flushing
 645        based on whether stdout appears to be redirected to a file or not.
 646
 647'GIT_TRACE'::
 648        If this variable is set to "1", "2" or "true" (comparison
 649        is case insensitive), git will print `trace:` messages on
 650        stderr telling about alias expansion, built-in command
 651        execution and external command execution.
 652        If this variable is set to an integer value greater than 1
 653        and lower than 10 (strictly) then git will interpret this
 654        value as an open file descriptor and will try to write the
 655        trace messages into this file descriptor.
 656        Alternatively, if this variable is set to an absolute path
 657        (starting with a '/' character), git will interpret this
 658        as a file path and will try to write the trace messages
 659        into it.
 660
 661Discussion[[Discussion]]
 662------------------------
 663
 664More detail on the following is available from the
 665link:user-manual.html#git-concepts[git concepts chapter of the
 666user-manual] and linkgit:gitcore-tutorial[7].
 667
 668A git project normally consists of a working directory with a ".git"
 669subdirectory at the top level.  The .git directory contains, among other
 670things, a compressed object database representing the complete history
 671of the project, an "index" file which links that history to the current
 672contents of the working tree, and named pointers into that history such
 673as tags and branch heads.
 674
 675The object database contains objects of three main types: blobs, which
 676hold file data; trees, which point to blobs and other trees to build up
 677directory hierarchies; and commits, which each reference a single tree
 678and some number of parent commits.
 679
 680The commit, equivalent to what other systems call a "changeset" or
 681"version", represents a step in the project's history, and each parent
 682represents an immediately preceding step.  Commits with more than one
 683parent represent merges of independent lines of development.
 684
 685All objects are named by the SHA1 hash of their contents, normally
 686written as a string of 40 hex digits.  Such names are globally unique.
 687The entire history leading up to a commit can be vouched for by signing
 688just that commit.  A fourth object type, the tag, is provided for this
 689purpose.
 690
 691When first created, objects are stored in individual files, but for
 692efficiency may later be compressed together into "pack files".
 693
 694Named pointers called refs mark interesting points in history.  A ref
 695may contain the SHA1 name of an object or the name of another ref.  Refs
 696with names beginning `ref/head/` contain the SHA1 name of the most
 697recent commit (or "head") of a branch under development.  SHA1 names of
 698tags of interest are stored under `ref/tags/`.  A special ref named
 699`HEAD` contains the name of the currently checked-out branch.
 700
 701The index file is initialized with a list of all paths and, for each
 702path, a blob object and a set of attributes.  The blob object represents
 703the contents of the file as of the head of the current branch.  The
 704attributes (last modified time, size, etc.) are taken from the
 705corresponding file in the working tree.  Subsequent changes to the
 706working tree can be found by comparing these attributes.  The index may
 707be updated with new content, and new commits may be created from the
 708content stored in the index.
 709
 710The index is also capable of storing multiple entries (called "stages")
 711for a given pathname.  These stages are used to hold the various
 712unmerged version of a file when a merge is in progress.
 713
 714Authors
 715-------
 716* git's founding father is Linus Torvalds <torvalds@osdl.org>.
 717* The current git nurse is Junio C Hamano <gitster@pobox.com>.
 718* The git potty was written by Andreas Ericsson <ae@op5.se>.
 719* General upbringing is handled by the git-list <git@vger.kernel.org>.
 720
 721Documentation
 722--------------
 723The documentation for git suite was started by David Greaves
 724<david@dgreaves.com>, and later enhanced greatly by the
 725contributors on the git-list <git@vger.kernel.org>.
 726
 727SEE ALSO
 728--------
 729linkgit:gittutorial[7], linkgit:gittutorial-2[7],
 730link:everyday.html[Everyday Git], linkgit:gitcvs-migration[7],
 731linkgit:gitglossary[7], linkgit:gitcore-tutorial[7],
 732linkgit:gitcli[7], link:user-manual.html[The Git User's Manual],
 733linkgit:gitworkflows[7]
 734
 735GIT
 736---
 737Part of the linkgit:git[1] suite