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