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:v1.7.3.1/git.html[documentation for release 1.7.3.1] 48 49* release notes for 50 link:RelNotes/1.7.3.1.txt[1.7.3.1], 51 link:RelNotes/1.7.3.txt[1.7.3]. 52 53* link:v1.7.2.3/git.html[documentation for release 1.7.2.3] 54 55* release notes for 56 link:RelNotes/1.7.2.3.txt[1.7.2.3], 57 link:RelNotes/1.7.2.2.txt[1.7.2.2], 58 link:RelNotes/1.7.2.1.txt[1.7.2.1], 59 link:RelNotes/1.7.2.txt[1.7.2]. 60 61* link:v1.7.1.2/git.html[documentation for release 1.7.1.2] 62 63* release notes for 64 link:RelNotes/1.7.1.2.txt[1.7.1.2], 65 link:RelNotes/1.7.1.1.txt[1.7.1.1], 66 link:RelNotes/1.7.1.txt[1.7.1]. 67 68* link:v1.7.0.7/git.html[documentation for release 1.7.0.7] 69 70* release notes for 71 link:RelNotes/1.7.0.7.txt[1.7.0.7], 72 link:RelNotes/1.7.0.6.txt[1.7.0.6], 73 link:RelNotes/1.7.0.5.txt[1.7.0.5], 74 link:RelNotes/1.7.0.4.txt[1.7.0.4], 75 link:RelNotes/1.7.0.3.txt[1.7.0.3], 76 link:RelNotes/1.7.0.2.txt[1.7.0.2], 77 link:RelNotes/1.7.0.1.txt[1.7.0.1], 78 link:RelNotes/1.7.0.txt[1.7.0]. 79 80* link:v1.6.6.2/git.html[documentation for release 1.6.6.2] 81 82* release notes for 83 link:RelNotes/1.6.6.2.txt[1.6.6.2], 84 link:RelNotes/1.6.6.1.txt[1.6.6.1], 85 link:RelNotes/1.6.6.txt[1.6.6]. 86 87* link:v1.6.5.8/git.html[documentation for release 1.6.5.8] 88 89* release notes for 90 link:RelNotes/1.6.5.8.txt[1.6.5.8], 91 link:RelNotes/1.6.5.7.txt[1.6.5.7], 92 link:RelNotes/1.6.5.6.txt[1.6.5.6], 93 link:RelNotes/1.6.5.5.txt[1.6.5.5], 94 link:RelNotes/1.6.5.4.txt[1.6.5.4], 95 link:RelNotes/1.6.5.3.txt[1.6.5.3], 96 link:RelNotes/1.6.5.2.txt[1.6.5.2], 97 link:RelNotes/1.6.5.1.txt[1.6.5.1], 98 link:RelNotes/1.6.5.txt[1.6.5]. 99 100* link:v1.6.4.4/git.html[documentation for release 1.6.4.4] 101 102* release notes for 103 link:RelNotes/1.6.4.4.txt[1.6.4.4], 104 link:RelNotes/1.6.4.3.txt[1.6.4.3], 105 link:RelNotes/1.6.4.2.txt[1.6.4.2], 106 link:RelNotes/1.6.4.1.txt[1.6.4.1], 107 link:RelNotes/1.6.4.txt[1.6.4]. 108 109* link:v1.6.3.4/git.html[documentation for release 1.6.3.4] 110 111* release notes for 112 link:RelNotes/1.6.3.4.txt[1.6.3.4], 113 link:RelNotes/1.6.3.3.txt[1.6.3.3], 114 link:RelNotes/1.6.3.2.txt[1.6.3.2], 115 link:RelNotes/1.6.3.1.txt[1.6.3.1], 116 link:RelNotes/1.6.3.txt[1.6.3]. 117 118* release notes for 119 link:RelNotes/1.6.2.5.txt[1.6.2.5], 120 link:RelNotes/1.6.2.4.txt[1.6.2.4], 121 link:RelNotes/1.6.2.3.txt[1.6.2.3], 122 link:RelNotes/1.6.2.2.txt[1.6.2.2], 123 link:RelNotes/1.6.2.1.txt[1.6.2.1], 124 link:RelNotes/1.6.2.txt[1.6.2]. 125 126* link:v1.6.1.3/git.html[documentation for release 1.6.1.3] 127 128* release notes for 129 link:RelNotes/1.6.1.3.txt[1.6.1.3], 130 link:RelNotes/1.6.1.2.txt[1.6.1.2], 131 link:RelNotes/1.6.1.1.txt[1.6.1.1], 132 link:RelNotes/1.6.1.txt[1.6.1]. 133 134* link:v1.6.0.6/git.html[documentation for release 1.6.0.6] 135 136* release notes for 137 link:RelNotes/1.6.0.6.txt[1.6.0.6], 138 link:RelNotes/1.6.0.5.txt[1.6.0.5], 139 link:RelNotes/1.6.0.4.txt[1.6.0.4], 140 link:RelNotes/1.6.0.3.txt[1.6.0.3], 141 link:RelNotes/1.6.0.2.txt[1.6.0.2], 142 link:RelNotes/1.6.0.1.txt[1.6.0.1], 143 link:RelNotes/1.6.0.txt[1.6.0]. 144 145* link:v1.5.6.6/git.html[documentation for release 1.5.6.6] 146 147* release notes for 148 link:RelNotes/1.5.6.6.txt[1.5.6.6], 149 link:RelNotes/1.5.6.5.txt[1.5.6.5], 150 link:RelNotes/1.5.6.4.txt[1.5.6.4], 151 link:RelNotes/1.5.6.3.txt[1.5.6.3], 152 link:RelNotes/1.5.6.2.txt[1.5.6.2], 153 link:RelNotes/1.5.6.1.txt[1.5.6.1], 154 link:RelNotes/1.5.6.txt[1.5.6]. 155 156* link:v1.5.5.6/git.html[documentation for release 1.5.5.6] 157 158* release notes for 159 link:RelNotes/1.5.5.6.txt[1.5.5.6], 160 link:RelNotes/1.5.5.5.txt[1.5.5.5], 161 link:RelNotes/1.5.5.4.txt[1.5.5.4], 162 link:RelNotes/1.5.5.3.txt[1.5.5.3], 163 link:RelNotes/1.5.5.2.txt[1.5.5.2], 164 link:RelNotes/1.5.5.1.txt[1.5.5.1], 165 link:RelNotes/1.5.5.txt[1.5.5]. 166 167* link:v1.5.4.7/git.html[documentation for release 1.5.4.7] 168 169* release notes for 170 link:RelNotes/1.5.4.7.txt[1.5.4.7], 171 link:RelNotes/1.5.4.6.txt[1.5.4.6], 172 link:RelNotes/1.5.4.5.txt[1.5.4.5], 173 link:RelNotes/1.5.4.4.txt[1.5.4.4], 174 link:RelNotes/1.5.4.3.txt[1.5.4.3], 175 link:RelNotes/1.5.4.2.txt[1.5.4.2], 176 link:RelNotes/1.5.4.1.txt[1.5.4.1], 177 link:RelNotes/1.5.4.txt[1.5.4]. 178 179* link:v1.5.3.8/git.html[documentation for release 1.5.3.8] 180 181* release notes for 182 link:RelNotes/1.5.3.8.txt[1.5.3.8], 183 link:RelNotes/1.5.3.7.txt[1.5.3.7], 184 link:RelNotes/1.5.3.6.txt[1.5.3.6], 185 link:RelNotes/1.5.3.5.txt[1.5.3.5], 186 link:RelNotes/1.5.3.4.txt[1.5.3.4], 187 link:RelNotes/1.5.3.3.txt[1.5.3.3], 188 link:RelNotes/1.5.3.2.txt[1.5.3.2], 189 link:RelNotes/1.5.3.1.txt[1.5.3.1], 190 link:RelNotes/1.5.3.txt[1.5.3]. 191 192* link:v1.5.2.5/git.html[documentation for release 1.5.2.5] 193 194* release notes for 195 link:RelNotes/1.5.2.5.txt[1.5.2.5], 196 link:RelNotes/1.5.2.4.txt[1.5.2.4], 197 link:RelNotes/1.5.2.3.txt[1.5.2.3], 198 link:RelNotes/1.5.2.2.txt[1.5.2.2], 199 link:RelNotes/1.5.2.1.txt[1.5.2.1], 200 link:RelNotes/1.5.2.txt[1.5.2]. 201 202* link:v1.5.1.6/git.html[documentation for release 1.5.1.6] 203 204* release notes for 205 link:RelNotes/1.5.1.6.txt[1.5.1.6], 206 link:RelNotes/1.5.1.5.txt[1.5.1.5], 207 link:RelNotes/1.5.1.4.txt[1.5.1.4], 208 link:RelNotes/1.5.1.3.txt[1.5.1.3], 209 link:RelNotes/1.5.1.2.txt[1.5.1.2], 210 link:RelNotes/1.5.1.1.txt[1.5.1.1], 211 link:RelNotes/1.5.1.txt[1.5.1]. 212 213* link:v1.5.0.7/git.html[documentation for release 1.5.0.7] 214 215* release notes for 216 link:RelNotes/1.5.0.7.txt[1.5.0.7], 217 link:RelNotes/1.5.0.6.txt[1.5.0.6], 218 link:RelNotes/1.5.0.5.txt[1.5.0.5], 219 link:RelNotes/1.5.0.3.txt[1.5.0.3], 220 link:RelNotes/1.5.0.2.txt[1.5.0.2], 221 link:RelNotes/1.5.0.1.txt[1.5.0.1], 222 link:RelNotes/1.5.0.txt[1.5.0]. 223 224* documentation for release link:v1.4.4.4/git.html[1.4.4.4], 225 link:v1.3.3/git.html[1.3.3], 226 link:v1.2.6/git.html[1.2.6], 227 link:v1.0.13/git.html[1.0.13]. 228 229============ 230 231endif::stalenotes[] 232 233OPTIONS 234------- 235--version:: 236 Prints the git suite version that the 'git' program came from. 237 238--help:: 239 Prints the synopsis and a list of the most commonly used 240 commands. If the option '--all' or '-a' is given then all 241 available commands are printed. If a git command is named this 242 option will bring up the manual page for that command. 243+ 244Other options are available to control how the manual page is 245displayed. See linkgit:git-help[1] for more information, 246because `git --help ...` is converted internally into `git 247help ...`. 248 249-c <name>=<value>:: 250 Pass a configuration parameter to the command. The value 251 given will override values from configuration files. 252 The <name> is expected in the same format as listed by 253 'git config' (subkeys separated by dots). 254 255--exec-path:: 256 Path to wherever your core git programs are installed. 257 This can also be controlled by setting the GIT_EXEC_PATH 258 environment variable. If no path is given, 'git' will print 259 the current setting and then exit. 260 261--html-path:: 262 Print the path to wherever your git HTML documentation is installed 263 and exit. 264 265-p:: 266--paginate:: 267 Pipe all output into 'less' (or if set, $PAGER) if standard 268 output is a terminal. This overrides the `pager.<cmd>` 269 configuration options (see the "Configuration Mechanism" section 270 below). 271 272--no-pager:: 273 Do not pipe git output into a pager. 274 275--git-dir=<path>:: 276 Set the path to the repository. This can also be controlled by 277 setting the GIT_DIR environment variable. It can be an absolute 278 path or relative path to current working directory. 279 280--work-tree=<path>:: 281 Set the path to the working tree. The value will not be 282 used in combination with repositories found automatically in 283 a .git directory (i.e. $GIT_DIR is not set). 284 This can also be controlled by setting the GIT_WORK_TREE 285 environment variable and the core.worktree configuration 286 variable. It can be an absolute path or relative path to 287 the directory specified by --git-dir or GIT_DIR. 288 Note: If --git-dir or GIT_DIR are specified but none of 289 --work-tree, GIT_WORK_TREE and core.worktree is specified, 290 the current working directory is regarded as the top directory 291 of your working tree. 292 293--bare:: 294 Treat the repository as a bare repository. If GIT_DIR 295 environment is not set, it is set to the current working 296 directory. 297 298--no-replace-objects:: 299 Do not use replacement refs to replace git objects. See 300 linkgit:git-replace[1] for more information. 301 302 303FURTHER DOCUMENTATION 304--------------------- 305 306See the references above to get started using git. The following is 307probably more detail than necessary for a first-time user. 308 309The link:user-manual.html#git-concepts[git concepts chapter of the 310user-manual] and linkgit:gitcore-tutorial[7] both provide 311introductions to the underlying git architecture. 312 313See linkgit:gitworkflows[7] for an overview of recommended workflows. 314 315See also the link:howto-index.html[howto] documents for some useful 316examples. 317 318The internals are documented in the 319link:technical/api-index.html[GIT API documentation]. 320 321GIT COMMANDS 322------------ 323 324We divide git into high level ("porcelain") commands and low level 325("plumbing") commands. 326 327High-level commands (porcelain) 328------------------------------- 329 330We separate the porcelain commands into the main commands and some 331ancillary user utilities. 332 333Main porcelain commands 334~~~~~~~~~~~~~~~~~~~~~~~ 335 336include::cmds-mainporcelain.txt[] 337 338Ancillary Commands 339~~~~~~~~~~~~~~~~~~ 340Manipulators: 341 342include::cmds-ancillarymanipulators.txt[] 343 344Interrogators: 345 346include::cmds-ancillaryinterrogators.txt[] 347 348 349Interacting with Others 350~~~~~~~~~~~~~~~~~~~~~~~ 351 352These commands are to interact with foreign SCM and with other 353people via patch over e-mail. 354 355include::cmds-foreignscminterface.txt[] 356 357 358Low-level commands (plumbing) 359----------------------------- 360 361Although git includes its 362own porcelain layer, its low-level commands are sufficient to support 363development of alternative porcelains. Developers of such porcelains 364might start by reading about linkgit:git-update-index[1] and 365linkgit:git-read-tree[1]. 366 367The interface (input, output, set of options and the semantics) 368to these low-level commands are meant to be a lot more stable 369than Porcelain level commands, because these commands are 370primarily for scripted use. The interface to Porcelain commands 371on the other hand are subject to change in order to improve the 372end user experience. 373 374The following description divides 375the low-level commands into commands that manipulate objects (in 376the repository, index, and working tree), commands that interrogate and 377compare objects, and commands that move objects and references between 378repositories. 379 380 381Manipulation commands 382~~~~~~~~~~~~~~~~~~~~~ 383 384include::cmds-plumbingmanipulators.txt[] 385 386 387Interrogation commands 388~~~~~~~~~~~~~~~~~~~~~~ 389 390include::cmds-plumbinginterrogators.txt[] 391 392In general, the interrogate commands do not touch the files in 393the working tree. 394 395 396Synching repositories 397~~~~~~~~~~~~~~~~~~~~~ 398 399include::cmds-synchingrepositories.txt[] 400 401The following are helper commands used by the above; end users 402typically do not use them directly. 403 404include::cmds-synchelpers.txt[] 405 406 407Internal helper commands 408~~~~~~~~~~~~~~~~~~~~~~~~ 409 410These are internal helper commands used by other commands; end 411users typically do not use them directly. 412 413include::cmds-purehelpers.txt[] 414 415 416Configuration Mechanism 417----------------------- 418 419Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file 420is used to hold per-repository configuration options. It is a 421simple text file modeled after `.ini` format familiar to some 422people. Here is an example: 423 424------------ 425# 426# A '#' or ';' character indicates a comment. 427# 428 429; core variables 430[core] 431 ; Don't trust file modes 432 filemode = false 433 434; user identity 435[user] 436 name = "Junio C Hamano" 437 email = "junkio@twinsun.com" 438 439------------ 440 441Various commands read from the configuration file and adjust 442their operation accordingly. See linkgit:git-config[1] for a 443list. 444 445 446Identifier Terminology 447---------------------- 448<object>:: 449 Indicates the object name for any type of object. 450 451<blob>:: 452 Indicates a blob object name. 453 454<tree>:: 455 Indicates a tree object name. 456 457<commit>:: 458 Indicates a commit object name. 459 460<tree-ish>:: 461 Indicates a tree, commit or tag object name. A 462 command that takes a <tree-ish> argument ultimately wants to 463 operate on a <tree> object but automatically dereferences 464 <commit> and <tag> objects that point at a <tree>. 465 466<commit-ish>:: 467 Indicates a commit or tag object name. A 468 command that takes a <commit-ish> argument ultimately wants to 469 operate on a <commit> object but automatically dereferences 470 <tag> objects that point at a <commit>. 471 472<type>:: 473 Indicates that an object type is required. 474 Currently one of: `blob`, `tree`, `commit`, or `tag`. 475 476<file>:: 477 Indicates a filename - almost always relative to the 478 root of the tree structure `GIT_INDEX_FILE` describes. 479 480Symbolic Identifiers 481-------------------- 482Any git command accepting any <object> can also use the following 483symbolic notation: 484 485HEAD:: 486 indicates the head of the current branch (i.e. the 487 contents of `$GIT_DIR/HEAD`). 488 489<tag>:: 490 a valid tag 'name' 491 (i.e. the contents of `$GIT_DIR/refs/tags/<tag>`). 492 493<head>:: 494 a valid head 'name' 495 (i.e. the contents of `$GIT_DIR/refs/heads/<head>`). 496 497For a more complete list of ways to spell object names, see 498"SPECIFYING REVISIONS" section in linkgit:gitrevisions[1]. 499 500 501File/Directory Structure 502------------------------ 503 504Please see the linkgit:gitrepository-layout[5] document. 505 506Read linkgit:githooks[5] for more details about each hook. 507 508Higher level SCMs may provide and manage additional information in the 509`$GIT_DIR`. 510 511 512Terminology 513----------- 514Please see linkgit:gitglossary[7]. 515 516 517Environment Variables 518--------------------- 519Various git commands use the following environment variables: 520 521The git Repository 522~~~~~~~~~~~~~~~~~~ 523These environment variables apply to 'all' core git commands. Nb: it 524is worth noting that they may be used/overridden by SCMS sitting above 525git so take care if using Cogito etc. 526 527'GIT_INDEX_FILE':: 528 This environment allows the specification of an alternate 529 index file. If not specified, the default of `$GIT_DIR/index` 530 is used. 531 532'GIT_OBJECT_DIRECTORY':: 533 If the object storage directory is specified via this 534 environment variable then the sha1 directories are created 535 underneath - otherwise the default `$GIT_DIR/objects` 536 directory is used. 537 538'GIT_ALTERNATE_OBJECT_DIRECTORIES':: 539 Due to the immutable nature of git objects, old objects can be 540 archived into shared, read-only directories. This variable 541 specifies a ":" separated (on Windows ";" separated) list 542 of git object directories which can be used to search for git 543 objects. New objects will not be written to these directories. 544 545'GIT_DIR':: 546 If the 'GIT_DIR' environment variable is set then it 547 specifies a path to use instead of the default `.git` 548 for the base of the repository. 549 550'GIT_WORK_TREE':: 551 Set the path to the working tree. The value will not be 552 used in combination with repositories found automatically in 553 a .git directory (i.e. $GIT_DIR is not set). 554 This can also be controlled by the '--work-tree' command line 555 option and the core.worktree configuration variable. 556 557'GIT_CEILING_DIRECTORIES':: 558 This should be a colon-separated list of absolute paths. 559 If set, it is a list of directories that git should not chdir 560 up into while looking for a repository directory. 561 It will not exclude the current working directory or 562 a GIT_DIR set on the command line or in the environment. 563 (Useful for excluding slow-loading network directories.) 564 565'GIT_DISCOVERY_ACROSS_FILESYSTEM':: 566 When run in a directory that does not have ".git" repository 567 directory, git tries to find such a directory in the parent 568 directories to find the top of the working tree, but by default it 569 does not cross filesystem boundaries. This environment variable 570 can be set to true to tell git not to stop at filesystem 571 boundaries. Like 'GIT_CEILING_DIRECTORIES', this will not affect 572 an explicit repository directory set via 'GIT_DIR' or on the 573 command line. 574 575git Commits 576~~~~~~~~~~~ 577'GIT_AUTHOR_NAME':: 578'GIT_AUTHOR_EMAIL':: 579'GIT_AUTHOR_DATE':: 580'GIT_COMMITTER_NAME':: 581'GIT_COMMITTER_EMAIL':: 582'GIT_COMMITTER_DATE':: 583'EMAIL':: 584 see linkgit:git-commit-tree[1] 585 586git Diffs 587~~~~~~~~~ 588'GIT_DIFF_OPTS':: 589 Only valid setting is "--unified=??" or "-u??" to set the 590 number of context lines shown when a unified diff is created. 591 This takes precedence over any "-U" or "--unified" option 592 value passed on the git diff command line. 593 594'GIT_EXTERNAL_DIFF':: 595 When the environment variable 'GIT_EXTERNAL_DIFF' is set, the 596 program named by it is called, instead of the diff invocation 597 described above. For a path that is added, removed, or modified, 598 'GIT_EXTERNAL_DIFF' is called with 7 parameters: 599 600 path old-file old-hex old-mode new-file new-hex new-mode 601+ 602where: 603 604 <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the 605 contents of <old|new>, 606 <old|new>-hex:: are the 40-hexdigit SHA1 hashes, 607 <old|new>-mode:: are the octal representation of the file modes. 608 609+ 610The file parameters can point at the user's working file 611(e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file` 612when a new file is added), or a temporary file (e.g. `old-file` in the 613index). 'GIT_EXTERNAL_DIFF' should not worry about unlinking the 614temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits. 615+ 616For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1 617parameter, <path>. 618 619other 620~~~~~ 621'GIT_MERGE_VERBOSITY':: 622 A number controlling the amount of output shown by 623 the recursive merge strategy. Overrides merge.verbosity. 624 See linkgit:git-merge[1] 625 626'GIT_PAGER':: 627 This environment variable overrides `$PAGER`. If it is set 628 to an empty string or to the value "cat", git will not launch 629 a pager. See also the `core.pager` option in 630 linkgit:git-config[1]. 631 632'GIT_SSH':: 633 If this environment variable is set then 'git fetch' 634 and 'git push' will use this command instead 635 of 'ssh' when they need to connect to a remote system. 636 The '$GIT_SSH' command will be given exactly two arguments: 637 the 'username@host' (or just 'host') from the URL and the 638 shell command to execute on that remote system. 639+ 640To pass options to the program that you want to list in GIT_SSH 641you will need to wrap the program and options into a shell script, 642then set GIT_SSH to refer to the shell script. 643+ 644Usually it is easier to configure any desired options through your 645personal `.ssh/config` file. Please consult your ssh documentation 646for further details. 647 648'GIT_ASKPASS':: 649 If this environment variable is set, then git commands which need to 650 acquire passwords or passphrases (e.g. for HTTP or IMAP authentication) 651 will call this program with a suitable prompt as command line argument 652 and read the password from its STDOUT. See also the 'core.askpass' 653 option in linkgit:git-config[1]. 654 655'GIT_FLUSH':: 656 If this environment variable is set to "1", then commands such 657 as 'git blame' (in incremental mode), 'git rev-list', 'git log', 658 and 'git whatchanged' will force a flush of the output stream 659 after each commit-oriented record have been flushed. If this 660 variable is set to "0", the output of these commands will be done 661 using completely buffered I/O. If this environment variable is 662 not set, git will choose buffered or record-oriented flushing 663 based on whether stdout appears to be redirected to a file or not. 664 665'GIT_TRACE':: 666 If this variable is set to "1", "2" or "true" (comparison 667 is case insensitive), git will print `trace:` messages on 668 stderr telling about alias expansion, built-in command 669 execution and external command execution. 670 If this variable is set to an integer value greater than 1 671 and lower than 10 (strictly) then git will interpret this 672 value as an open file descriptor and will try to write the 673 trace messages into this file descriptor. 674 Alternatively, if this variable is set to an absolute path 675 (starting with a '/' character), git will interpret this 676 as a file path and will try to write the trace messages 677 into it. 678 679Discussion[[Discussion]] 680------------------------ 681 682More detail on the following is available from the 683link:user-manual.html#git-concepts[git concepts chapter of the 684user-manual] and linkgit:gitcore-tutorial[7]. 685 686A git project normally consists of a working directory with a ".git" 687subdirectory at the top level. The .git directory contains, among other 688things, a compressed object database representing the complete history 689of the project, an "index" file which links that history to the current 690contents of the working tree, and named pointers into that history such 691as tags and branch heads. 692 693The object database contains objects of three main types: blobs, which 694hold file data; trees, which point to blobs and other trees to build up 695directory hierarchies; and commits, which each reference a single tree 696and some number of parent commits. 697 698The commit, equivalent to what other systems call a "changeset" or 699"version", represents a step in the project's history, and each parent 700represents an immediately preceding step. Commits with more than one 701parent represent merges of independent lines of development. 702 703All objects are named by the SHA1 hash of their contents, normally 704written as a string of 40 hex digits. Such names are globally unique. 705The entire history leading up to a commit can be vouched for by signing 706just that commit. A fourth object type, the tag, is provided for this 707purpose. 708 709When first created, objects are stored in individual files, but for 710efficiency may later be compressed together into "pack files". 711 712Named pointers called refs mark interesting points in history. A ref 713may contain the SHA1 name of an object or the name of another ref. Refs 714with names beginning `ref/head/` contain the SHA1 name of the most 715recent commit (or "head") of a branch under development. SHA1 names of 716tags of interest are stored under `ref/tags/`. A special ref named 717`HEAD` contains the name of the currently checked-out branch. 718 719The index file is initialized with a list of all paths and, for each 720path, a blob object and a set of attributes. The blob object represents 721the contents of the file as of the head of the current branch. The 722attributes (last modified time, size, etc.) are taken from the 723corresponding file in the working tree. Subsequent changes to the 724working tree can be found by comparing these attributes. The index may 725be updated with new content, and new commits may be created from the 726content stored in the index. 727 728The index is also capable of storing multiple entries (called "stages") 729for a given pathname. These stages are used to hold the various 730unmerged version of a file when a merge is in progress. 731 732Authors 733------- 734* git's founding father is Linus Torvalds <torvalds@osdl.org>. 735* The current git nurse is Junio C Hamano <gitster@pobox.com>. 736* The git potty was written by Andreas Ericsson <ae@op5.se>. 737* General upbringing is handled by the git-list <git@vger.kernel.org>. 738 739Documentation 740-------------- 741The documentation for git suite was started by David Greaves 742<david@dgreaves.com>, and later enhanced greatly by the 743contributors on the git-list <git@vger.kernel.org>. 744 745Reporting Bugs 746-------------- 747 748Report bugs to the Git mailing list <git@vger.kernel.org> where the 749development and maintenance is primarily done. You do not have to be 750subscribed to the list to send a message there. 751 752SEE ALSO 753-------- 754linkgit:gittutorial[7], linkgit:gittutorial-2[7], 755link:everyday.html[Everyday Git], linkgit:gitcvs-migration[7], 756linkgit:gitglossary[7], linkgit:gitcore-tutorial[7], 757linkgit:gitcli[7], link:user-manual.html[The Git User's Manual], 758linkgit:gitworkflows[7] 759 760GIT 761--- 762Part of the linkgit:git[1] suite