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 548git Commits 549~~~~~~~~~~~ 550'GIT_AUTHOR_NAME':: 551'GIT_AUTHOR_EMAIL':: 552'GIT_AUTHOR_DATE':: 553'GIT_COMMITTER_NAME':: 554'GIT_COMMITTER_EMAIL':: 555'GIT_COMMITTER_DATE':: 556'EMAIL':: 557 see linkgit:git-commit-tree[1] 558 559git Diffs 560~~~~~~~~~ 561'GIT_DIFF_OPTS':: 562 Only valid setting is "--unified=??" or "-u??" to set the 563 number of context lines shown when a unified diff is created. 564 This takes precedence over any "-U" or "--unified" option 565 value passed on the git diff command line. 566 567'GIT_EXTERNAL_DIFF':: 568 When the environment variable 'GIT_EXTERNAL_DIFF' is set, the 569 program named by it is called, instead of the diff invocation 570 described above. For a path that is added, removed, or modified, 571 'GIT_EXTERNAL_DIFF' is called with 7 parameters: 572 573 path old-file old-hex old-mode new-file new-hex new-mode 574+ 575where: 576 577 <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the 578 contents of <old|new>, 579 <old|new>-hex:: are the 40-hexdigit SHA1 hashes, 580 <old|new>-mode:: are the octal representation of the file modes. 581 582+ 583The file parameters can point at the user's working file 584(e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file` 585when a new file is added), or a temporary file (e.g. `old-file` in the 586index). 'GIT_EXTERNAL_DIFF' should not worry about unlinking the 587temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits. 588+ 589For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1 590parameter, <path>. 591 592other 593~~~~~ 594'GIT_MERGE_VERBOSITY':: 595 A number controlling the amount of output shown by 596 the recursive merge strategy. Overrides merge.verbosity. 597 See linkgit:git-merge[1] 598 599'GIT_PAGER':: 600 This environment variable overrides `$PAGER`. If it is set 601 to an empty string or to the value "cat", git will not launch 602 a pager. See also the `core.pager` option in 603 linkgit:git-config[1]. 604 605'GIT_SSH':: 606 If this environment variable is set then 'git fetch' 607 and 'git push' will use this command instead 608 of 'ssh' when they need to connect to a remote system. 609 The '$GIT_SSH' command will be given exactly two arguments: 610 the 'username@host' (or just 'host') from the URL and the 611 shell command to execute on that remote system. 612+ 613To pass options to the program that you want to list in GIT_SSH 614you will need to wrap the program and options into a shell script, 615then set GIT_SSH to refer to the shell script. 616+ 617Usually it is easier to configure any desired options through your 618personal `.ssh/config` file. Please consult your ssh documentation 619for further details. 620 621'GIT_FLUSH':: 622 If this environment variable is set to "1", then commands such 623 as 'git blame' (in incremental mode), 'git rev-list', 'git log', 624 and 'git whatchanged' will force a flush of the output stream 625 after each commit-oriented record have been flushed. If this 626 variable is set to "0", the output of these commands will be done 627 using completely buffered I/O. If this environment variable is 628 not set, git will choose buffered or record-oriented flushing 629 based on whether stdout appears to be redirected to a file or not. 630 631'GIT_TRACE':: 632 If this variable is set to "1", "2" or "true" (comparison 633 is case insensitive), git will print `trace:` messages on 634 stderr telling about alias expansion, built-in command 635 execution and external command execution. 636 If this variable is set to an integer value greater than 1 637 and lower than 10 (strictly) then git will interpret this 638 value as an open file descriptor and will try to write the 639 trace messages into this file descriptor. 640 Alternatively, if this variable is set to an absolute path 641 (starting with a '/' character), git will interpret this 642 as a file path and will try to write the trace messages 643 into it. 644 645Discussion[[Discussion]] 646------------------------ 647 648More detail on the following is available from the 649link:user-manual.html#git-concepts[git concepts chapter of the 650user-manual] and linkgit:gitcore-tutorial[7]. 651 652A git project normally consists of a working directory with a ".git" 653subdirectory at the top level. The .git directory contains, among other 654things, a compressed object database representing the complete history 655of the project, an "index" file which links that history to the current 656contents of the working tree, and named pointers into that history such 657as tags and branch heads. 658 659The object database contains objects of three main types: blobs, which 660hold file data; trees, which point to blobs and other trees to build up 661directory hierarchies; and commits, which each reference a single tree 662and some number of parent commits. 663 664The commit, equivalent to what other systems call a "changeset" or 665"version", represents a step in the project's history, and each parent 666represents an immediately preceding step. Commits with more than one 667parent represent merges of independent lines of development. 668 669All objects are named by the SHA1 hash of their contents, normally 670written as a string of 40 hex digits. Such names are globally unique. 671The entire history leading up to a commit can be vouched for by signing 672just that commit. A fourth object type, the tag, is provided for this 673purpose. 674 675When first created, objects are stored in individual files, but for 676efficiency may later be compressed together into "pack files". 677 678Named pointers called refs mark interesting points in history. A ref 679may contain the SHA1 name of an object or the name of another ref. Refs 680with names beginning `ref/head/` contain the SHA1 name of the most 681recent commit (or "head") of a branch under development. SHA1 names of 682tags of interest are stored under `ref/tags/`. A special ref named 683`HEAD` contains the name of the currently checked-out branch. 684 685The index file is initialized with a list of all paths and, for each 686path, a blob object and a set of attributes. The blob object represents 687the contents of the file as of the head of the current branch. The 688attributes (last modified time, size, etc.) are taken from the 689corresponding file in the working tree. Subsequent changes to the 690working tree can be found by comparing these attributes. The index may 691be updated with new content, and new commits may be created from the 692content stored in the index. 693 694The index is also capable of storing multiple entries (called "stages") 695for a given pathname. These stages are used to hold the various 696unmerged version of a file when a merge is in progress. 697 698Authors 699------- 700* git's founding father is Linus Torvalds <torvalds@osdl.org>. 701* The current git nurse is Junio C Hamano <gitster@pobox.com>. 702* The git potty was written by Andreas Ericsson <ae@op5.se>. 703* General upbringing is handled by the git-list <git@vger.kernel.org>. 704 705Documentation 706-------------- 707The documentation for git suite was started by David Greaves 708<david@dgreaves.com>, and later enhanced greatly by the 709contributors on the git-list <git@vger.kernel.org>. 710 711SEE ALSO 712-------- 713linkgit:gittutorial[7], linkgit:gittutorial-2[7], 714link:everyday.html[Everyday Git], linkgit:gitcvs-migration[7], 715linkgit:gitglossary[7], linkgit:gitcore-tutorial[7], 716linkgit:gitcli[7], link:user-manual.html[The Git User's Manual], 717linkgit:gitworkflows[7] 718 719GIT 720--- 721Part of the linkgit:git[1] suite