1git(1) 2====== 3 4NAME 5---- 6git - the stupid content tracker 7 8 9SYNOPSIS 10-------- 11[verse] 12'git' [--version] [--exec-path[=GIT_EXEC_PATH]] [--html-path] 13 [-p|--paginate|--no-pager] [--no-replace-objects] 14 [--bare] [--git-dir=GIT_DIR] [--work-tree=GIT_WORK_TREE] 15 [--help] COMMAND [ARGS] 16 17DESCRIPTION 18----------- 19Git is a fast, scalable, distributed revision control system with an 20unusually rich command set that provides both high-level operations 21and full access to internals. 22 23See linkgit:gittutorial[7] to get started, then see 24link:everyday.html[Everyday Git] for a useful minimum set of commands, and 25"man git-commandname" for documentation of each command. CVS users may 26also want to read linkgit:gitcvs-migration[7]. See 27the link:user-manual.html[Git User's Manual] for a more in-depth 28introduction. 29 30The COMMAND is either a name of a Git command (see below) or an alias 31as defined in the configuration file (see linkgit:git-config[1]). 32 33Formatted and hyperlinked version of the latest git 34documentation can be viewed at 35`http://www.kernel.org/pub/software/scm/git/docs/`. 36 37ifdef::stalenotes[] 38[NOTE] 39============ 40 41You are reading the documentation for the latest (possibly 42unreleased) version of git, that is available from 'master' 43branch of the `git.git` repository. 44Documentation for older releases are available here: 45 46 47* link:v1.7.1.2/git.html[documentation for release 1.7.1.2] 48 49* release notes for 50 link:RelNotes-1.7.1.2.txt[1.7.1.2], 51 link:RelNotes-1.7.1.1.txt[1.7.1.1], 52 link:RelNotes-1.7.1.txt[1.7.1]. 53 54* link:v1.7.0.7/git.html[documentation for release 1.7.0.7] 55 56* release notes for 57 link:RelNotes-1.7.0.7.txt[1.7.0.7], 58 link:RelNotes-1.7.0.6.txt[1.7.0.6], 59 link:RelNotes-1.7.0.5.txt[1.7.0.5], 60 link:RelNotes-1.7.0.4.txt[1.7.0.4], 61 link:RelNotes-1.7.0.3.txt[1.7.0.3], 62 link:RelNotes-1.7.0.2.txt[1.7.0.2], 63 link:RelNotes-1.7.0.1.txt[1.7.0.1], 64 link:RelNotes-1.7.0.txt[1.7.0]. 65 66* link:v1.6.6.2/git.html[documentation for release 1.6.6.2] 67 68* release notes for 69 link:RelNotes-1.6.6.2.txt[1.6.6.2], 70 link:RelNotes-1.6.6.1.txt[1.6.6.1], 71 link:RelNotes-1.6.6.txt[1.6.6]. 72 73* link:v1.6.5.8/git.html[documentation for release 1.6.5.8] 74 75* release notes for 76 link:RelNotes-1.6.5.8.txt[1.6.5.8], 77 link:RelNotes-1.6.5.7.txt[1.6.5.7], 78 link:RelNotes-1.6.5.6.txt[1.6.5.6], 79 link:RelNotes-1.6.5.5.txt[1.6.5.5], 80 link:RelNotes-1.6.5.4.txt[1.6.5.4], 81 link:RelNotes-1.6.5.3.txt[1.6.5.3], 82 link:RelNotes-1.6.5.2.txt[1.6.5.2], 83 link:RelNotes-1.6.5.1.txt[1.6.5.1], 84 link:RelNotes-1.6.5.txt[1.6.5]. 85 86* link:v1.6.4.4/git.html[documentation for release 1.6.4.4] 87 88* release notes for 89 link:RelNotes-1.6.4.4.txt[1.6.4.4], 90 link:RelNotes-1.6.4.3.txt[1.6.4.3], 91 link:RelNotes-1.6.4.2.txt[1.6.4.2], 92 link:RelNotes-1.6.4.1.txt[1.6.4.1], 93 link:RelNotes-1.6.4.txt[1.6.4]. 94 95* link:v1.6.3.4/git.html[documentation for release 1.6.3.4] 96 97* release notes for 98 link:RelNotes-1.6.3.4.txt[1.6.3.4], 99 link:RelNotes-1.6.3.3.txt[1.6.3.3], 100 link:RelNotes-1.6.3.2.txt[1.6.3.2], 101 link:RelNotes-1.6.3.1.txt[1.6.3.1], 102 link:RelNotes-1.6.3.txt[1.6.3]. 103 104* release notes for 105 link:RelNotes-1.6.2.5.txt[1.6.2.5], 106 link:RelNotes-1.6.2.4.txt[1.6.2.4], 107 link:RelNotes-1.6.2.3.txt[1.6.2.3], 108 link:RelNotes-1.6.2.2.txt[1.6.2.2], 109 link:RelNotes-1.6.2.1.txt[1.6.2.1], 110 link:RelNotes-1.6.2.txt[1.6.2]. 111 112* link:v1.6.1.3/git.html[documentation for release 1.6.1.3] 113 114* release notes for 115 link:RelNotes-1.6.1.3.txt[1.6.1.3], 116 link:RelNotes-1.6.1.2.txt[1.6.1.2], 117 link:RelNotes-1.6.1.1.txt[1.6.1.1], 118 link:RelNotes-1.6.1.txt[1.6.1]. 119 120* link:v1.6.0.6/git.html[documentation for release 1.6.0.6] 121 122* release notes for 123 link:RelNotes-1.6.0.6.txt[1.6.0.6], 124 link:RelNotes-1.6.0.5.txt[1.6.0.5], 125 link:RelNotes-1.6.0.4.txt[1.6.0.4], 126 link:RelNotes-1.6.0.3.txt[1.6.0.3], 127 link:RelNotes-1.6.0.2.txt[1.6.0.2], 128 link:RelNotes-1.6.0.1.txt[1.6.0.1], 129 link:RelNotes-1.6.0.txt[1.6.0]. 130 131* link:v1.5.6.6/git.html[documentation for release 1.5.6.6] 132 133* release notes for 134 link:RelNotes-1.5.6.6.txt[1.5.6.6], 135 link:RelNotes-1.5.6.5.txt[1.5.6.5], 136 link:RelNotes-1.5.6.4.txt[1.5.6.4], 137 link:RelNotes-1.5.6.3.txt[1.5.6.3], 138 link:RelNotes-1.5.6.2.txt[1.5.6.2], 139 link:RelNotes-1.5.6.1.txt[1.5.6.1], 140 link:RelNotes-1.5.6.txt[1.5.6]. 141 142* link:v1.5.5.6/git.html[documentation for release 1.5.5.6] 143 144* release notes for 145 link:RelNotes-1.5.5.6.txt[1.5.5.6], 146 link:RelNotes-1.5.5.5.txt[1.5.5.5], 147 link:RelNotes-1.5.5.4.txt[1.5.5.4], 148 link:RelNotes-1.5.5.3.txt[1.5.5.3], 149 link:RelNotes-1.5.5.2.txt[1.5.5.2], 150 link:RelNotes-1.5.5.1.txt[1.5.5.1], 151 link:RelNotes-1.5.5.txt[1.5.5]. 152 153* link:v1.5.4.7/git.html[documentation for release 1.5.4.7] 154 155* release notes for 156 link:RelNotes-1.5.4.7.txt[1.5.4.7], 157 link:RelNotes-1.5.4.6.txt[1.5.4.6], 158 link:RelNotes-1.5.4.5.txt[1.5.4.5], 159 link:RelNotes-1.5.4.4.txt[1.5.4.4], 160 link:RelNotes-1.5.4.3.txt[1.5.4.3], 161 link:RelNotes-1.5.4.2.txt[1.5.4.2], 162 link:RelNotes-1.5.4.1.txt[1.5.4.1], 163 link:RelNotes-1.5.4.txt[1.5.4]. 164 165* link:v1.5.3.8/git.html[documentation for release 1.5.3.8] 166 167* release notes for 168 link:RelNotes-1.5.3.8.txt[1.5.3.8], 169 link:RelNotes-1.5.3.7.txt[1.5.3.7], 170 link:RelNotes-1.5.3.6.txt[1.5.3.6], 171 link:RelNotes-1.5.3.5.txt[1.5.3.5], 172 link:RelNotes-1.5.3.4.txt[1.5.3.4], 173 link:RelNotes-1.5.3.3.txt[1.5.3.3], 174 link:RelNotes-1.5.3.2.txt[1.5.3.2], 175 link:RelNotes-1.5.3.1.txt[1.5.3.1], 176 link:RelNotes-1.5.3.txt[1.5.3]. 177 178* link:v1.5.2.5/git.html[documentation for release 1.5.2.5] 179 180* release notes for 181 link:RelNotes-1.5.2.5.txt[1.5.2.5], 182 link:RelNotes-1.5.2.4.txt[1.5.2.4], 183 link:RelNotes-1.5.2.3.txt[1.5.2.3], 184 link:RelNotes-1.5.2.2.txt[1.5.2.2], 185 link:RelNotes-1.5.2.1.txt[1.5.2.1], 186 link:RelNotes-1.5.2.txt[1.5.2]. 187 188* link:v1.5.1.6/git.html[documentation for release 1.5.1.6] 189 190* release notes for 191 link:RelNotes-1.5.1.6.txt[1.5.1.6], 192 link:RelNotes-1.5.1.5.txt[1.5.1.5], 193 link:RelNotes-1.5.1.4.txt[1.5.1.4], 194 link:RelNotes-1.5.1.3.txt[1.5.1.3], 195 link:RelNotes-1.5.1.2.txt[1.5.1.2], 196 link:RelNotes-1.5.1.1.txt[1.5.1.1], 197 link:RelNotes-1.5.1.txt[1.5.1]. 198 199* link:v1.5.0.7/git.html[documentation for release 1.5.0.7] 200 201* release notes for 202 link:RelNotes-1.5.0.7.txt[1.5.0.7], 203 link:RelNotes-1.5.0.6.txt[1.5.0.6], 204 link:RelNotes-1.5.0.5.txt[1.5.0.5], 205 link:RelNotes-1.5.0.3.txt[1.5.0.3], 206 link:RelNotes-1.5.0.2.txt[1.5.0.2], 207 link:RelNotes-1.5.0.1.txt[1.5.0.1], 208 link:RelNotes-1.5.0.txt[1.5.0]. 209 210* documentation for release link:v1.4.4.4/git.html[1.4.4.4], 211 link:v1.3.3/git.html[1.3.3], 212 link:v1.2.6/git.html[1.2.6], 213 link:v1.0.13/git.html[1.0.13]. 214 215============ 216 217endif::stalenotes[] 218 219OPTIONS 220------- 221--version:: 222 Prints the git suite version that the 'git' program came from. 223 224--help:: 225 Prints the synopsis and a list of the most commonly used 226 commands. If the option '--all' or '-a' is given then all 227 available commands are printed. If a git command is named this 228 option will bring up the manual page for that command. 229+ 230Other options are available to control how the manual page is 231displayed. See linkgit:git-help[1] for more information, 232because `git --help ...` is converted internally into `git 233help ...`. 234 235--exec-path:: 236 Path to wherever your core git programs are installed. 237 This can also be controlled by setting the GIT_EXEC_PATH 238 environment variable. If no path is given, 'git' will print 239 the current setting and then exit. 240 241--html-path:: 242 Print the path to wherever your git HTML documentation is installed 243 and exit. 244 245-p:: 246--paginate:: 247 Pipe all output into 'less' (or if set, $PAGER) if standard 248 output is a terminal. This overrides the `pager.<cmd>` 249 configuration options (see the "Configuration Mechanism" section 250 below). 251 252--no-pager:: 253 Do not pipe git output into a pager. 254 255--git-dir=<path>:: 256 Set the path to the repository. This can also be controlled by 257 setting the GIT_DIR environment variable. It can be an absolute 258 path or relative path to current working directory. 259 260--work-tree=<path>:: 261 Set the path to the working tree. The value will not be 262 used in combination with repositories found automatically in 263 a .git directory (i.e. $GIT_DIR is not set). 264 This can also be controlled by setting the GIT_WORK_TREE 265 environment variable and the core.worktree configuration 266 variable. It can be an absolute path or relative path to 267 the directory specified by --git-dir or GIT_DIR. 268 Note: If --git-dir or GIT_DIR are specified but none of 269 --work-tree, GIT_WORK_TREE and core.worktree is specified, 270 the current working directory is regarded as the top directory 271 of your working tree. 272 273--bare:: 274 Treat the repository as a bare repository. If GIT_DIR 275 environment is not set, it is set to the current working 276 directory. 277 278--no-replace-objects:: 279 Do not use replacement refs to replace git objects. See 280 linkgit:git-replace[1] for more information. 281 282 283FURTHER DOCUMENTATION 284--------------------- 285 286See the references above to get started using git. The following is 287probably more detail than necessary for a first-time user. 288 289The link:user-manual.html#git-concepts[git concepts chapter of the 290user-manual] and linkgit:gitcore-tutorial[7] both provide 291introductions to the underlying git architecture. 292 293See linkgit:gitworkflows[7] for an overview of recommended workflows. 294 295See also the link:howto-index.html[howto] documents for some useful 296examples. 297 298The internals are documented in the 299link:technical/api-index.html[GIT API documentation]. 300 301GIT COMMANDS 302------------ 303 304We divide git into high level ("porcelain") commands and low level 305("plumbing") commands. 306 307High-level commands (porcelain) 308------------------------------- 309 310We separate the porcelain commands into the main commands and some 311ancillary user utilities. 312 313Main porcelain commands 314~~~~~~~~~~~~~~~~~~~~~~~ 315 316include::cmds-mainporcelain.txt[] 317 318Ancillary Commands 319~~~~~~~~~~~~~~~~~~ 320Manipulators: 321 322include::cmds-ancillarymanipulators.txt[] 323 324Interrogators: 325 326include::cmds-ancillaryinterrogators.txt[] 327 328 329Interacting with Others 330~~~~~~~~~~~~~~~~~~~~~~~ 331 332These commands are to interact with foreign SCM and with other 333people via patch over e-mail. 334 335include::cmds-foreignscminterface.txt[] 336 337 338Low-level commands (plumbing) 339----------------------------- 340 341Although git includes its 342own porcelain layer, its low-level commands are sufficient to support 343development of alternative porcelains. Developers of such porcelains 344might start by reading about linkgit:git-update-index[1] and 345linkgit:git-read-tree[1]. 346 347The interface (input, output, set of options and the semantics) 348to these low-level commands are meant to be a lot more stable 349than Porcelain level commands, because these commands are 350primarily for scripted use. The interface to Porcelain commands 351on the other hand are subject to change in order to improve the 352end user experience. 353 354The following description divides 355the low-level commands into commands that manipulate objects (in 356the repository, index, and working tree), commands that interrogate and 357compare objects, and commands that move objects and references between 358repositories. 359 360 361Manipulation commands 362~~~~~~~~~~~~~~~~~~~~~ 363 364include::cmds-plumbingmanipulators.txt[] 365 366 367Interrogation commands 368~~~~~~~~~~~~~~~~~~~~~~ 369 370include::cmds-plumbinginterrogators.txt[] 371 372In general, the interrogate commands do not touch the files in 373the working tree. 374 375 376Synching repositories 377~~~~~~~~~~~~~~~~~~~~~ 378 379include::cmds-synchingrepositories.txt[] 380 381The following are helper commands used by the above; end users 382typically do not use them directly. 383 384include::cmds-synchelpers.txt[] 385 386 387Internal helper commands 388~~~~~~~~~~~~~~~~~~~~~~~~ 389 390These are internal helper commands used by other commands; end 391users typically do not use them directly. 392 393include::cmds-purehelpers.txt[] 394 395 396Configuration Mechanism 397----------------------- 398 399Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file 400is used to hold per-repository configuration options. It is a 401simple text file modeled after `.ini` format familiar to some 402people. Here is an example: 403 404------------ 405# 406# A '#' or ';' character indicates a comment. 407# 408 409; core variables 410[core] 411 ; Don't trust file modes 412 filemode = false 413 414; user identity 415[user] 416 name = "Junio C Hamano" 417 email = "junkio@twinsun.com" 418 419------------ 420 421Various commands read from the configuration file and adjust 422their operation accordingly. See linkgit:git-config[1] for a 423list. 424 425 426Identifier Terminology 427---------------------- 428<object>:: 429 Indicates the object name for any type of object. 430 431<blob>:: 432 Indicates a blob object name. 433 434<tree>:: 435 Indicates a tree object name. 436 437<commit>:: 438 Indicates a commit object name. 439 440<tree-ish>:: 441 Indicates a tree, commit or tag object name. A 442 command that takes a <tree-ish> argument ultimately wants to 443 operate on a <tree> object but automatically dereferences 444 <commit> and <tag> objects that point at a <tree>. 445 446<commit-ish>:: 447 Indicates a commit or tag object name. A 448 command that takes a <commit-ish> argument ultimately wants to 449 operate on a <commit> object but automatically dereferences 450 <tag> objects that point at a <commit>. 451 452<type>:: 453 Indicates that an object type is required. 454 Currently one of: `blob`, `tree`, `commit`, or `tag`. 455 456<file>:: 457 Indicates a filename - almost always relative to the 458 root of the tree structure `GIT_INDEX_FILE` describes. 459 460Symbolic Identifiers 461-------------------- 462Any git command accepting any <object> can also use the following 463symbolic notation: 464 465HEAD:: 466 indicates the head of the current branch (i.e. the 467 contents of `$GIT_DIR/HEAD`). 468 469<tag>:: 470 a valid tag 'name' 471 (i.e. the contents of `$GIT_DIR/refs/tags/<tag>`). 472 473<head>:: 474 a valid head 'name' 475 (i.e. the contents of `$GIT_DIR/refs/heads/<head>`). 476 477For a more complete list of ways to spell object names, see 478"SPECIFYING REVISIONS" section in linkgit:git-rev-parse[1]. 479 480 481File/Directory Structure 482------------------------ 483 484Please see the linkgit:gitrepository-layout[5] document. 485 486Read linkgit:githooks[5] for more details about each hook. 487 488Higher level SCMs may provide and manage additional information in the 489`$GIT_DIR`. 490 491 492Terminology 493----------- 494Please see linkgit:gitglossary[7]. 495 496 497Environment Variables 498--------------------- 499Various git commands use the following environment variables: 500 501The git Repository 502~~~~~~~~~~~~~~~~~~ 503These environment variables apply to 'all' core git commands. Nb: it 504is worth noting that they may be used/overridden by SCMS sitting above 505git so take care if using Cogito etc. 506 507'GIT_INDEX_FILE':: 508 This environment allows the specification of an alternate 509 index file. If not specified, the default of `$GIT_DIR/index` 510 is used. 511 512'GIT_OBJECT_DIRECTORY':: 513 If the object storage directory is specified via this 514 environment variable then the sha1 directories are created 515 underneath - otherwise the default `$GIT_DIR/objects` 516 directory is used. 517 518'GIT_ALTERNATE_OBJECT_DIRECTORIES':: 519 Due to the immutable nature of git objects, old objects can be 520 archived into shared, read-only directories. This variable 521 specifies a ":" separated (on Windows ";" separated) list 522 of git object directories which can be used to search for git 523 objects. New objects will not be written to these directories. 524 525'GIT_DIR':: 526 If the 'GIT_DIR' environment variable is set then it 527 specifies a path to use instead of the default `.git` 528 for the base of the repository. 529 530'GIT_WORK_TREE':: 531 Set the path to the working tree. The value will not be 532 used in combination with repositories found automatically in 533 a .git directory (i.e. $GIT_DIR is not set). 534 This can also be controlled by the '--work-tree' command line 535 option and the core.worktree configuration variable. 536 537'GIT_CEILING_DIRECTORIES':: 538 This should be a colon-separated list of absolute paths. 539 If set, it is a list of directories that git should not chdir 540 up into while looking for a repository directory. 541 It will not exclude the current working directory or 542 a GIT_DIR set on the command line or in the environment. 543 (Useful for excluding slow-loading network directories.) 544 545git Commits 546~~~~~~~~~~~ 547'GIT_AUTHOR_NAME':: 548'GIT_AUTHOR_EMAIL':: 549'GIT_AUTHOR_DATE':: 550'GIT_COMMITTER_NAME':: 551'GIT_COMMITTER_EMAIL':: 552'GIT_COMMITTER_DATE':: 553'EMAIL':: 554 see linkgit:git-commit-tree[1] 555 556git Diffs 557~~~~~~~~~ 558'GIT_DIFF_OPTS':: 559 Only valid setting is "--unified=??" or "-u??" to set the 560 number of context lines shown when a unified diff is created. 561 This takes precedence over any "-U" or "--unified" option 562 value passed on the git diff command line. 563 564'GIT_EXTERNAL_DIFF':: 565 When the environment variable 'GIT_EXTERNAL_DIFF' is set, the 566 program named by it is called, instead of the diff invocation 567 described above. For a path that is added, removed, or modified, 568 'GIT_EXTERNAL_DIFF' is called with 7 parameters: 569 570 path old-file old-hex old-mode new-file new-hex new-mode 571+ 572where: 573 574 <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the 575 contents of <old|new>, 576 <old|new>-hex:: are the 40-hexdigit SHA1 hashes, 577 <old|new>-mode:: are the octal representation of the file modes. 578 579+ 580The file parameters can point at the user's working file 581(e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file` 582when a new file is added), or a temporary file (e.g. `old-file` in the 583index). 'GIT_EXTERNAL_DIFF' should not worry about unlinking the 584temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits. 585+ 586For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1 587parameter, <path>. 588 589other 590~~~~~ 591'GIT_MERGE_VERBOSITY':: 592 A number controlling the amount of output shown by 593 the recursive merge strategy. Overrides merge.verbosity. 594 See linkgit:git-merge[1] 595 596'GIT_PAGER':: 597 This environment variable overrides `$PAGER`. If it is set 598 to an empty string or to the value "cat", git will not launch 599 a pager. See also the `core.pager` option in 600 linkgit:git-config[1]. 601 602'GIT_SSH':: 603 If this environment variable is set then 'git fetch' 604 and 'git push' will use this command instead 605 of 'ssh' when they need to connect to a remote system. 606 The '$GIT_SSH' command will be given exactly two arguments: 607 the 'username@host' (or just 'host') from the URL and the 608 shell command to execute on that remote system. 609+ 610To pass options to the program that you want to list in GIT_SSH 611you will need to wrap the program and options into a shell script, 612then set GIT_SSH to refer to the shell script. 613+ 614Usually it is easier to configure any desired options through your 615personal `.ssh/config` file. Please consult your ssh documentation 616for further details. 617 618'GIT_FLUSH':: 619 If this environment variable is set to "1", then commands such 620 as 'git blame' (in incremental mode), 'git rev-list', 'git log', 621 and 'git whatchanged' will force a flush of the output stream 622 after each commit-oriented record have been flushed. If this 623 variable is set to "0", the output of these commands will be done 624 using completely buffered I/O. If this environment variable is 625 not set, git will choose buffered or record-oriented flushing 626 based on whether stdout appears to be redirected to a file or not. 627 628'GIT_TRACE':: 629 If this variable is set to "1", "2" or "true" (comparison 630 is case insensitive), git will print `trace:` messages on 631 stderr telling about alias expansion, built-in command 632 execution and external command execution. 633 If this variable is set to an integer value greater than 1 634 and lower than 10 (strictly) then git will interpret this 635 value as an open file descriptor and will try to write the 636 trace messages into this file descriptor. 637 Alternatively, if this variable is set to an absolute path 638 (starting with a '/' character), git will interpret this 639 as a file path and will try to write the trace messages 640 into it. 641 642Discussion[[Discussion]] 643------------------------ 644 645More detail on the following is available from the 646link:user-manual.html#git-concepts[git concepts chapter of the 647user-manual] and linkgit:gitcore-tutorial[7]. 648 649A git project normally consists of a working directory with a ".git" 650subdirectory at the top level. The .git directory contains, among other 651things, a compressed object database representing the complete history 652of the project, an "index" file which links that history to the current 653contents of the working tree, and named pointers into that history such 654as tags and branch heads. 655 656The object database contains objects of three main types: blobs, which 657hold file data; trees, which point to blobs and other trees to build up 658directory hierarchies; and commits, which each reference a single tree 659and some number of parent commits. 660 661The commit, equivalent to what other systems call a "changeset" or 662"version", represents a step in the project's history, and each parent 663represents an immediately preceding step. Commits with more than one 664parent represent merges of independent lines of development. 665 666All objects are named by the SHA1 hash of their contents, normally 667written as a string of 40 hex digits. Such names are globally unique. 668The entire history leading up to a commit can be vouched for by signing 669just that commit. A fourth object type, the tag, is provided for this 670purpose. 671 672When first created, objects are stored in individual files, but for 673efficiency may later be compressed together into "pack files". 674 675Named pointers called refs mark interesting points in history. A ref 676may contain the SHA1 name of an object or the name of another ref. Refs 677with names beginning `ref/head/` contain the SHA1 name of the most 678recent commit (or "head") of a branch under development. SHA1 names of 679tags of interest are stored under `ref/tags/`. A special ref named 680`HEAD` contains the name of the currently checked-out branch. 681 682The index file is initialized with a list of all paths and, for each 683path, a blob object and a set of attributes. The blob object represents 684the contents of the file as of the head of the current branch. The 685attributes (last modified time, size, etc.) are taken from the 686corresponding file in the working tree. Subsequent changes to the 687working tree can be found by comparing these attributes. The index may 688be updated with new content, and new commits may be created from the 689content stored in the index. 690 691The index is also capable of storing multiple entries (called "stages") 692for a given pathname. These stages are used to hold the various 693unmerged version of a file when a merge is in progress. 694 695Authors 696------- 697* git's founding father is Linus Torvalds <torvalds@osdl.org>. 698* The current git nurse is Junio C Hamano <gitster@pobox.com>. 699* The git potty was written by Andreas Ericsson <ae@op5.se>. 700* General upbringing is handled by the git-list <git@vger.kernel.org>. 701 702Documentation 703-------------- 704The documentation for git suite was started by David Greaves 705<david@dgreaves.com>, and later enhanced greatly by the 706contributors on the git-list <git@vger.kernel.org>. 707 708SEE ALSO 709-------- 710linkgit:gittutorial[7], linkgit:gittutorial-2[7], 711link:everyday.html[Everyday Git], linkgit:gitcvs-migration[7], 712linkgit:gitglossary[7], linkgit:gitcore-tutorial[7], 713linkgit:gitcli[7], link:user-manual.html[The Git User's Manual], 714linkgit:gitworkflows[7] 715 716GIT 717--- 718Part of the linkgit:git[1] suite