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