1git(1) 2====== 3 4NAME 5---- 6git - the stupid content tracker 7 8 9SYNOPSIS 10-------- 11[verse] 12'git' [--version] [--exec-path[=<path>]] [--html-path] [--man-path] [--info-path] 13 [-p|--paginate|--no-pager] [--no-replace-objects] 14 [--bare] [--git-dir=<path>] [--work-tree=<path>] 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:v1.7.6/git.html[documentation for release 1.7.6] 48 49* release notes for 50 link:RelNotes/1.7.6.txt[1.7.6]. 51 52* link:v1.7.5.4/git.html[documentation for release 1.7.5.4] 53 54* release notes for 55 link:RelNotes/1.7.5.4.txt[1.7.5.4], 56 link:RelNotes/1.7.5.3.txt[1.7.5.3], 57 link:RelNotes/1.7.5.2.txt[1.7.5.2], 58 link:RelNotes/1.7.5.1.txt[1.7.5.1], 59 link:RelNotes/1.7.5.txt[1.7.5]. 60 61* link:v1.7.4.5/git.html[documentation for release 1.7.4.5] 62 63* release notes for 64 link:RelNotes/1.7.4.5.txt[1.7.4.5], 65 link:RelNotes/1.7.4.4.txt[1.7.4.4], 66 link:RelNotes/1.7.4.3.txt[1.7.4.3], 67 link:RelNotes/1.7.4.2.txt[1.7.4.2], 68 link:RelNotes/1.7.4.1.txt[1.7.4.1], 69 link:RelNotes/1.7.4.txt[1.7.4]. 70 71* link:v1.7.3.5/git.html[documentation for release 1.7.3.5] 72 73* release notes for 74 link:RelNotes/1.7.3.5.txt[1.7.3.5], 75 link:RelNotes/1.7.3.4.txt[1.7.3.4], 76 link:RelNotes/1.7.3.3.txt[1.7.3.3], 77 link:RelNotes/1.7.3.2.txt[1.7.3.2], 78 link:RelNotes/1.7.3.1.txt[1.7.3.1], 79 link:RelNotes/1.7.3.txt[1.7.3]. 80 81* link:v1.7.2.5/git.html[documentation for release 1.7.2.5] 82 83* release notes for 84 link:RelNotes/1.7.2.5.txt[1.7.2.5], 85 link:RelNotes/1.7.2.4.txt[1.7.2.4], 86 link:RelNotes/1.7.2.3.txt[1.7.2.3], 87 link:RelNotes/1.7.2.2.txt[1.7.2.2], 88 link:RelNotes/1.7.2.1.txt[1.7.2.1], 89 link:RelNotes/1.7.2.txt[1.7.2]. 90 91* link:v1.7.1.4/git.html[documentation for release 1.7.1.4] 92 93* release notes for 94 link:RelNotes/1.7.1.4.txt[1.7.1.4], 95 link:RelNotes/1.7.1.3.txt[1.7.1.3], 96 link:RelNotes/1.7.1.2.txt[1.7.1.2], 97 link:RelNotes/1.7.1.1.txt[1.7.1.1], 98 link:RelNotes/1.7.1.txt[1.7.1]. 99 100* link:v1.7.0.9/git.html[documentation for release 1.7.0.9] 101 102* release notes for 103 link:RelNotes/1.7.0.9.txt[1.7.0.9], 104 link:RelNotes/1.7.0.8.txt[1.7.0.8], 105 link:RelNotes/1.7.0.7.txt[1.7.0.7], 106 link:RelNotes/1.7.0.6.txt[1.7.0.6], 107 link:RelNotes/1.7.0.5.txt[1.7.0.5], 108 link:RelNotes/1.7.0.4.txt[1.7.0.4], 109 link:RelNotes/1.7.0.3.txt[1.7.0.3], 110 link:RelNotes/1.7.0.2.txt[1.7.0.2], 111 link:RelNotes/1.7.0.1.txt[1.7.0.1], 112 link:RelNotes/1.7.0.txt[1.7.0]. 113 114* link:v1.6.6.3/git.html[documentation for release 1.6.6.3] 115 116* release notes for 117 link:RelNotes/1.6.6.3.txt[1.6.6.3], 118 link:RelNotes/1.6.6.2.txt[1.6.6.2], 119 link:RelNotes/1.6.6.1.txt[1.6.6.1], 120 link:RelNotes/1.6.6.txt[1.6.6]. 121 122* link:v1.6.5.9/git.html[documentation for release 1.6.5.9] 123 124* release notes for 125 link:RelNotes/1.6.5.9.txt[1.6.5.9], 126 link:RelNotes/1.6.5.8.txt[1.6.5.8], 127 link:RelNotes/1.6.5.7.txt[1.6.5.7], 128 link:RelNotes/1.6.5.6.txt[1.6.5.6], 129 link:RelNotes/1.6.5.5.txt[1.6.5.5], 130 link:RelNotes/1.6.5.4.txt[1.6.5.4], 131 link:RelNotes/1.6.5.3.txt[1.6.5.3], 132 link:RelNotes/1.6.5.2.txt[1.6.5.2], 133 link:RelNotes/1.6.5.1.txt[1.6.5.1], 134 link:RelNotes/1.6.5.txt[1.6.5]. 135 136* link:v1.6.4.5/git.html[documentation for release 1.6.4.5] 137 138* release notes for 139 link:RelNotes/1.6.4.5.txt[1.6.4.5], 140 link:RelNotes/1.6.4.4.txt[1.6.4.4], 141 link:RelNotes/1.6.4.3.txt[1.6.4.3], 142 link:RelNotes/1.6.4.2.txt[1.6.4.2], 143 link:RelNotes/1.6.4.1.txt[1.6.4.1], 144 link:RelNotes/1.6.4.txt[1.6.4]. 145 146* link:v1.6.3.4/git.html[documentation for release 1.6.3.4] 147 148* release notes for 149 link:RelNotes/1.6.3.4.txt[1.6.3.4], 150 link:RelNotes/1.6.3.3.txt[1.6.3.3], 151 link:RelNotes/1.6.3.2.txt[1.6.3.2], 152 link:RelNotes/1.6.3.1.txt[1.6.3.1], 153 link:RelNotes/1.6.3.txt[1.6.3]. 154 155* release notes for 156 link:RelNotes/1.6.2.5.txt[1.6.2.5], 157 link:RelNotes/1.6.2.4.txt[1.6.2.4], 158 link:RelNotes/1.6.2.3.txt[1.6.2.3], 159 link:RelNotes/1.6.2.2.txt[1.6.2.2], 160 link:RelNotes/1.6.2.1.txt[1.6.2.1], 161 link:RelNotes/1.6.2.txt[1.6.2]. 162 163* link:v1.6.1.3/git.html[documentation for release 1.6.1.3] 164 165* release notes for 166 link:RelNotes/1.6.1.3.txt[1.6.1.3], 167 link:RelNotes/1.6.1.2.txt[1.6.1.2], 168 link:RelNotes/1.6.1.1.txt[1.6.1.1], 169 link:RelNotes/1.6.1.txt[1.6.1]. 170 171* link:v1.6.0.6/git.html[documentation for release 1.6.0.6] 172 173* release notes for 174 link:RelNotes/1.6.0.6.txt[1.6.0.6], 175 link:RelNotes/1.6.0.5.txt[1.6.0.5], 176 link:RelNotes/1.6.0.4.txt[1.6.0.4], 177 link:RelNotes/1.6.0.3.txt[1.6.0.3], 178 link:RelNotes/1.6.0.2.txt[1.6.0.2], 179 link:RelNotes/1.6.0.1.txt[1.6.0.1], 180 link:RelNotes/1.6.0.txt[1.6.0]. 181 182* link:v1.5.6.6/git.html[documentation for release 1.5.6.6] 183 184* release notes for 185 link:RelNotes/1.5.6.6.txt[1.5.6.6], 186 link:RelNotes/1.5.6.5.txt[1.5.6.5], 187 link:RelNotes/1.5.6.4.txt[1.5.6.4], 188 link:RelNotes/1.5.6.3.txt[1.5.6.3], 189 link:RelNotes/1.5.6.2.txt[1.5.6.2], 190 link:RelNotes/1.5.6.1.txt[1.5.6.1], 191 link:RelNotes/1.5.6.txt[1.5.6]. 192 193* link:v1.5.5.6/git.html[documentation for release 1.5.5.6] 194 195* release notes for 196 link:RelNotes/1.5.5.6.txt[1.5.5.6], 197 link:RelNotes/1.5.5.5.txt[1.5.5.5], 198 link:RelNotes/1.5.5.4.txt[1.5.5.4], 199 link:RelNotes/1.5.5.3.txt[1.5.5.3], 200 link:RelNotes/1.5.5.2.txt[1.5.5.2], 201 link:RelNotes/1.5.5.1.txt[1.5.5.1], 202 link:RelNotes/1.5.5.txt[1.5.5]. 203 204* link:v1.5.4.7/git.html[documentation for release 1.5.4.7] 205 206* release notes for 207 link:RelNotes/1.5.4.7.txt[1.5.4.7], 208 link:RelNotes/1.5.4.6.txt[1.5.4.6], 209 link:RelNotes/1.5.4.5.txt[1.5.4.5], 210 link:RelNotes/1.5.4.4.txt[1.5.4.4], 211 link:RelNotes/1.5.4.3.txt[1.5.4.3], 212 link:RelNotes/1.5.4.2.txt[1.5.4.2], 213 link:RelNotes/1.5.4.1.txt[1.5.4.1], 214 link:RelNotes/1.5.4.txt[1.5.4]. 215 216* link:v1.5.3.8/git.html[documentation for release 1.5.3.8] 217 218* release notes for 219 link:RelNotes/1.5.3.8.txt[1.5.3.8], 220 link:RelNotes/1.5.3.7.txt[1.5.3.7], 221 link:RelNotes/1.5.3.6.txt[1.5.3.6], 222 link:RelNotes/1.5.3.5.txt[1.5.3.5], 223 link:RelNotes/1.5.3.4.txt[1.5.3.4], 224 link:RelNotes/1.5.3.3.txt[1.5.3.3], 225 link:RelNotes/1.5.3.2.txt[1.5.3.2], 226 link:RelNotes/1.5.3.1.txt[1.5.3.1], 227 link:RelNotes/1.5.3.txt[1.5.3]. 228 229* link:v1.5.2.5/git.html[documentation for release 1.5.2.5] 230 231* release notes for 232 link:RelNotes/1.5.2.5.txt[1.5.2.5], 233 link:RelNotes/1.5.2.4.txt[1.5.2.4], 234 link:RelNotes/1.5.2.3.txt[1.5.2.3], 235 link:RelNotes/1.5.2.2.txt[1.5.2.2], 236 link:RelNotes/1.5.2.1.txt[1.5.2.1], 237 link:RelNotes/1.5.2.txt[1.5.2]. 238 239* link:v1.5.1.6/git.html[documentation for release 1.5.1.6] 240 241* release notes for 242 link:RelNotes/1.5.1.6.txt[1.5.1.6], 243 link:RelNotes/1.5.1.5.txt[1.5.1.5], 244 link:RelNotes/1.5.1.4.txt[1.5.1.4], 245 link:RelNotes/1.5.1.3.txt[1.5.1.3], 246 link:RelNotes/1.5.1.2.txt[1.5.1.2], 247 link:RelNotes/1.5.1.1.txt[1.5.1.1], 248 link:RelNotes/1.5.1.txt[1.5.1]. 249 250* link:v1.5.0.7/git.html[documentation for release 1.5.0.7] 251 252* release notes for 253 link:RelNotes/1.5.0.7.txt[1.5.0.7], 254 link:RelNotes/1.5.0.6.txt[1.5.0.6], 255 link:RelNotes/1.5.0.5.txt[1.5.0.5], 256 link:RelNotes/1.5.0.3.txt[1.5.0.3], 257 link:RelNotes/1.5.0.2.txt[1.5.0.2], 258 link:RelNotes/1.5.0.1.txt[1.5.0.1], 259 link:RelNotes/1.5.0.txt[1.5.0]. 260 261* documentation for release link:v1.4.4.4/git.html[1.4.4.4], 262 link:v1.3.3/git.html[1.3.3], 263 link:v1.2.6/git.html[1.2.6], 264 link:v1.0.13/git.html[1.0.13]. 265 266============ 267 268endif::stalenotes[] 269 270OPTIONS 271------- 272--version:: 273 Prints the git suite version that the 'git' program came from. 274 275--help:: 276 Prints the synopsis and a list of the most commonly used 277 commands. If the option '--all' or '-a' is given then all 278 available commands are printed. If a git command is named this 279 option will bring up the manual page for that command. 280+ 281Other options are available to control how the manual page is 282displayed. See linkgit:git-help[1] for more information, 283because `git --help ...` is converted internally into `git 284help ...`. 285 286-c <name>=<value>:: 287 Pass a configuration parameter to the command. The value 288 given will override values from configuration files. 289 The <name> is expected in the same format as listed by 290 'git config' (subkeys separated by dots). 291 292--exec-path[=<path>]:: 293 Path to wherever your core git programs are installed. 294 This can also be controlled by setting the GIT_EXEC_PATH 295 environment variable. If no path is given, 'git' will print 296 the current setting and then exit. 297 298--html-path:: 299 Print the path, without trailing slash, where git's HTML 300 documentation is installed and exit. 301 302--man-path:: 303 Print the manpath (see `man(1)`) for the man pages for 304 this version of git and exit. 305 306--info-path:: 307 Print the path where the Info files documenting this 308 version of git are installed and exit. 309 310-p:: 311--paginate:: 312 Pipe all output into 'less' (or if set, $PAGER) if standard 313 output is a terminal. This overrides the `pager.<cmd>` 314 configuration options (see the "Configuration Mechanism" section 315 below). 316 317--no-pager:: 318 Do not pipe git output into a pager. 319 320--git-dir=<path>:: 321 Set the path to the repository. This can also be controlled by 322 setting the GIT_DIR environment variable. It can be an absolute 323 path or relative path to current working directory. 324 325--work-tree=<path>:: 326 Set the path to the working tree. It can be an absolute path 327 or a path relative to the current working directory. 328 This can also be controlled by setting the GIT_WORK_TREE 329 environment variable and the core.worktree configuration 330 variable (see core.worktree in linkgit:git-config[1] for a 331 more detailed discussion). 332 333--bare:: 334 Treat the repository as a bare repository. If GIT_DIR 335 environment is not set, it is set to the current working 336 directory. 337 338--no-replace-objects:: 339 Do not use replacement refs to replace git objects. See 340 linkgit:git-replace[1] for more information. 341 342 343FURTHER DOCUMENTATION 344--------------------- 345 346See the references above to get started using git. The following is 347probably more detail than necessary for a first-time user. 348 349The link:user-manual.html#git-concepts[git concepts chapter of the 350user-manual] and linkgit:gitcore-tutorial[7] both provide 351introductions to the underlying git architecture. 352 353See linkgit:gitworkflows[7] for an overview of recommended workflows. 354 355See also the link:howto-index.html[howto] documents for some useful 356examples. 357 358The internals are documented in the 359link:technical/api-index.html[GIT API documentation]. 360 361GIT COMMANDS 362------------ 363 364We divide git into high level ("porcelain") commands and low level 365("plumbing") commands. 366 367High-level commands (porcelain) 368------------------------------- 369 370We separate the porcelain commands into the main commands and some 371ancillary user utilities. 372 373Main porcelain commands 374~~~~~~~~~~~~~~~~~~~~~~~ 375 376include::cmds-mainporcelain.txt[] 377 378Ancillary Commands 379~~~~~~~~~~~~~~~~~~ 380Manipulators: 381 382include::cmds-ancillarymanipulators.txt[] 383 384Interrogators: 385 386include::cmds-ancillaryinterrogators.txt[] 387 388 389Interacting with Others 390~~~~~~~~~~~~~~~~~~~~~~~ 391 392These commands are to interact with foreign SCM and with other 393people via patch over e-mail. 394 395include::cmds-foreignscminterface.txt[] 396 397 398Low-level commands (plumbing) 399----------------------------- 400 401Although git includes its 402own porcelain layer, its low-level commands are sufficient to support 403development of alternative porcelains. Developers of such porcelains 404might start by reading about linkgit:git-update-index[1] and 405linkgit:git-read-tree[1]. 406 407The interface (input, output, set of options and the semantics) 408to these low-level commands are meant to be a lot more stable 409than Porcelain level commands, because these commands are 410primarily for scripted use. The interface to Porcelain commands 411on the other hand are subject to change in order to improve the 412end user experience. 413 414The following description divides 415the low-level commands into commands that manipulate objects (in 416the repository, index, and working tree), commands that interrogate and 417compare objects, and commands that move objects and references between 418repositories. 419 420 421Manipulation commands 422~~~~~~~~~~~~~~~~~~~~~ 423 424include::cmds-plumbingmanipulators.txt[] 425 426 427Interrogation commands 428~~~~~~~~~~~~~~~~~~~~~~ 429 430include::cmds-plumbinginterrogators.txt[] 431 432In general, the interrogate commands do not touch the files in 433the working tree. 434 435 436Synching repositories 437~~~~~~~~~~~~~~~~~~~~~ 438 439include::cmds-synchingrepositories.txt[] 440 441The following are helper commands used by the above; end users 442typically do not use them directly. 443 444include::cmds-synchelpers.txt[] 445 446 447Internal helper commands 448~~~~~~~~~~~~~~~~~~~~~~~~ 449 450These are internal helper commands used by other commands; end 451users typically do not use them directly. 452 453include::cmds-purehelpers.txt[] 454 455 456Configuration Mechanism 457----------------------- 458 459Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file 460is used to hold per-repository configuration options. It is a 461simple text file modeled after `.ini` format familiar to some 462people. Here is an example: 463 464------------ 465# 466# A '#' or ';' character indicates a comment. 467# 468 469; core variables 470[core] 471 ; Don't trust file modes 472 filemode = false 473 474; user identity 475[user] 476 name = "Junio C Hamano" 477 email = "junkio@twinsun.com" 478 479------------ 480 481Various commands read from the configuration file and adjust 482their operation accordingly. See linkgit:git-config[1] for a 483list. 484 485 486Identifier Terminology 487---------------------- 488<object>:: 489 Indicates the object name for any type of object. 490 491<blob>:: 492 Indicates a blob object name. 493 494<tree>:: 495 Indicates a tree object name. 496 497<commit>:: 498 Indicates a commit object name. 499 500<tree-ish>:: 501 Indicates a tree, commit or tag object name. A 502 command that takes a <tree-ish> argument ultimately wants to 503 operate on a <tree> object but automatically dereferences 504 <commit> and <tag> objects that point at a <tree>. 505 506<commit-ish>:: 507 Indicates a commit or tag object name. A 508 command that takes a <commit-ish> argument ultimately wants to 509 operate on a <commit> object but automatically dereferences 510 <tag> objects that point at a <commit>. 511 512<type>:: 513 Indicates that an object type is required. 514 Currently one of: `blob`, `tree`, `commit`, or `tag`. 515 516<file>:: 517 Indicates a filename - almost always relative to the 518 root of the tree structure `GIT_INDEX_FILE` describes. 519 520Symbolic Identifiers 521-------------------- 522Any git command accepting any <object> can also use the following 523symbolic notation: 524 525HEAD:: 526 indicates the head of the current branch (i.e. the 527 contents of `$GIT_DIR/HEAD`). 528 529<tag>:: 530 a valid tag 'name' 531 (i.e. the contents of `$GIT_DIR/refs/tags/<tag>`). 532 533<head>:: 534 a valid head 'name' 535 (i.e. the contents of `$GIT_DIR/refs/heads/<head>`). 536 537For a more complete list of ways to spell object names, see 538"SPECIFYING REVISIONS" section in linkgit:gitrevisions[7]. 539 540 541File/Directory Structure 542------------------------ 543 544Please see the linkgit:gitrepository-layout[5] document. 545 546Read linkgit:githooks[5] for more details about each hook. 547 548Higher level SCMs may provide and manage additional information in the 549`$GIT_DIR`. 550 551 552Terminology 553----------- 554Please see linkgit:gitglossary[7]. 555 556 557Environment Variables 558--------------------- 559Various git commands use the following environment variables: 560 561The git Repository 562~~~~~~~~~~~~~~~~~~ 563These environment variables apply to 'all' core git commands. Nb: it 564is worth noting that they may be used/overridden by SCMS sitting above 565git so take care if using Cogito etc. 566 567'GIT_INDEX_FILE':: 568 This environment allows the specification of an alternate 569 index file. If not specified, the default of `$GIT_DIR/index` 570 is used. 571 572'GIT_OBJECT_DIRECTORY':: 573 If the object storage directory is specified via this 574 environment variable then the sha1 directories are created 575 underneath - otherwise the default `$GIT_DIR/objects` 576 directory is used. 577 578'GIT_ALTERNATE_OBJECT_DIRECTORIES':: 579 Due to the immutable nature of git objects, old objects can be 580 archived into shared, read-only directories. This variable 581 specifies a ":" separated (on Windows ";" separated) list 582 of git object directories which can be used to search for git 583 objects. New objects will not be written to these directories. 584 585'GIT_DIR':: 586 If the 'GIT_DIR' environment variable is set then it 587 specifies a path to use instead of the default `.git` 588 for the base of the repository. 589 590'GIT_WORK_TREE':: 591 Set the path to the working tree. The value will not be 592 used in combination with repositories found automatically in 593 a .git directory (i.e. $GIT_DIR is not set). 594 This can also be controlled by the '--work-tree' command line 595 option and the core.worktree configuration variable. 596 597'GIT_CEILING_DIRECTORIES':: 598 This should be a colon-separated list of absolute paths. 599 If set, it is a list of directories that git should not chdir 600 up into while looking for a repository directory. 601 It will not exclude the current working directory or 602 a GIT_DIR set on the command line or in the environment. 603 (Useful for excluding slow-loading network directories.) 604 605'GIT_DISCOVERY_ACROSS_FILESYSTEM':: 606 When run in a directory that does not have ".git" repository 607 directory, git tries to find such a directory in the parent 608 directories to find the top of the working tree, but by default it 609 does not cross filesystem boundaries. This environment variable 610 can be set to true to tell git not to stop at filesystem 611 boundaries. Like 'GIT_CEILING_DIRECTORIES', this will not affect 612 an explicit repository directory set via 'GIT_DIR' or on the 613 command line. 614 615git Commits 616~~~~~~~~~~~ 617'GIT_AUTHOR_NAME':: 618'GIT_AUTHOR_EMAIL':: 619'GIT_AUTHOR_DATE':: 620'GIT_COMMITTER_NAME':: 621'GIT_COMMITTER_EMAIL':: 622'GIT_COMMITTER_DATE':: 623'EMAIL':: 624 see linkgit:git-commit-tree[1] 625 626git Diffs 627~~~~~~~~~ 628'GIT_DIFF_OPTS':: 629 Only valid setting is "--unified=??" or "-u??" to set the 630 number of context lines shown when a unified diff is created. 631 This takes precedence over any "-U" or "--unified" option 632 value passed on the git diff command line. 633 634'GIT_EXTERNAL_DIFF':: 635 When the environment variable 'GIT_EXTERNAL_DIFF' is set, the 636 program named by it is called, instead of the diff invocation 637 described above. For a path that is added, removed, or modified, 638 'GIT_EXTERNAL_DIFF' is called with 7 parameters: 639 640 path old-file old-hex old-mode new-file new-hex new-mode 641+ 642where: 643 644 <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the 645 contents of <old|new>, 646 <old|new>-hex:: are the 40-hexdigit SHA1 hashes, 647 <old|new>-mode:: are the octal representation of the file modes. 648+ 649The file parameters can point at the user's working file 650(e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file` 651when a new file is added), or a temporary file (e.g. `old-file` in the 652index). 'GIT_EXTERNAL_DIFF' should not worry about unlinking the 653temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits. 654+ 655For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1 656parameter, <path>. 657 658other 659~~~~~ 660'GIT_MERGE_VERBOSITY':: 661 A number controlling the amount of output shown by 662 the recursive merge strategy. Overrides merge.verbosity. 663 See linkgit:git-merge[1] 664 665'GIT_PAGER':: 666 This environment variable overrides `$PAGER`. If it is set 667 to an empty string or to the value "cat", git will not launch 668 a pager. See also the `core.pager` option in 669 linkgit:git-config[1]. 670 671'GIT_SSH':: 672 If this environment variable is set then 'git fetch' 673 and 'git push' will use this command instead 674 of 'ssh' when they need to connect to a remote system. 675 The '$GIT_SSH' command will be given exactly two arguments: 676 the 'username@host' (or just 'host') from the URL and the 677 shell command to execute on that remote system. 678+ 679To pass options to the program that you want to list in GIT_SSH 680you will need to wrap the program and options into a shell script, 681then set GIT_SSH to refer to the shell script. 682+ 683Usually it is easier to configure any desired options through your 684personal `.ssh/config` file. Please consult your ssh documentation 685for further details. 686 687'GIT_ASKPASS':: 688 If this environment variable is set, then git commands which need to 689 acquire passwords or passphrases (e.g. for HTTP or IMAP authentication) 690 will call this program with a suitable prompt as command line argument 691 and read the password from its STDOUT. See also the 'core.askpass' 692 option in linkgit:git-config[1]. 693 694'GIT_FLUSH':: 695 If this environment variable is set to "1", then commands such 696 as 'git blame' (in incremental mode), 'git rev-list', 'git log', 697 and 'git whatchanged' will force a flush of the output stream 698 after each commit-oriented record have been flushed. If this 699 variable is set to "0", the output of these commands will be done 700 using completely buffered I/O. If this environment variable is 701 not set, git will choose buffered or record-oriented flushing 702 based on whether stdout appears to be redirected to a file or not. 703 704'GIT_TRACE':: 705 If this variable is set to "1", "2" or "true" (comparison 706 is case insensitive), git will print `trace:` messages on 707 stderr telling about alias expansion, built-in command 708 execution and external command execution. 709 If this variable is set to an integer value greater than 1 710 and lower than 10 (strictly) then git will interpret this 711 value as an open file descriptor and will try to write the 712 trace messages into this file descriptor. 713 Alternatively, if this variable is set to an absolute path 714 (starting with a '/' character), git will interpret this 715 as a file path and will try to write the trace messages 716 into it. 717 718Discussion[[Discussion]] 719------------------------ 720 721More detail on the following is available from the 722link:user-manual.html#git-concepts[git concepts chapter of the 723user-manual] and linkgit:gitcore-tutorial[7]. 724 725A git project normally consists of a working directory with a ".git" 726subdirectory at the top level. The .git directory contains, among other 727things, a compressed object database representing the complete history 728of the project, an "index" file which links that history to the current 729contents of the working tree, and named pointers into that history such 730as tags and branch heads. 731 732The object database contains objects of three main types: blobs, which 733hold file data; trees, which point to blobs and other trees to build up 734directory hierarchies; and commits, which each reference a single tree 735and some number of parent commits. 736 737The commit, equivalent to what other systems call a "changeset" or 738"version", represents a step in the project's history, and each parent 739represents an immediately preceding step. Commits with more than one 740parent represent merges of independent lines of development. 741 742All objects are named by the SHA1 hash of their contents, normally 743written as a string of 40 hex digits. Such names are globally unique. 744The entire history leading up to a commit can be vouched for by signing 745just that commit. A fourth object type, the tag, is provided for this 746purpose. 747 748When first created, objects are stored in individual files, but for 749efficiency may later be compressed together into "pack files". 750 751Named pointers called refs mark interesting points in history. A ref 752may contain the SHA1 name of an object or the name of another ref. Refs 753with names beginning `ref/head/` contain the SHA1 name of the most 754recent commit (or "head") of a branch under development. SHA1 names of 755tags of interest are stored under `ref/tags/`. A special ref named 756`HEAD` contains the name of the currently checked-out branch. 757 758The index file is initialized with a list of all paths and, for each 759path, a blob object and a set of attributes. The blob object represents 760the contents of the file as of the head of the current branch. The 761attributes (last modified time, size, etc.) are taken from the 762corresponding file in the working tree. Subsequent changes to the 763working tree can be found by comparing these attributes. The index may 764be updated with new content, and new commits may be created from the 765content stored in the index. 766 767The index is also capable of storing multiple entries (called "stages") 768for a given pathname. These stages are used to hold the various 769unmerged version of a file when a merge is in progress. 770 771Authors 772------- 773Git was started by Linus Torvalds, and is currently maintained by Junio 774C Hamano. Numerous contributions have come from the git mailing list 775<git@vger.kernel.org>. For a more complete list of contributors, see 776http://git-scm.com/about. If you have a clone of git.git itself, the 777output of linkgit:git-shortlog[1] and linkgit:git-blame[1] can show you 778the authors for specific parts of the project. 779 780Reporting Bugs 781-------------- 782 783Report bugs to the Git mailing list <git@vger.kernel.org> where the 784development and maintenance is primarily done. You do not have to be 785subscribed to the list to send a message there. 786 787SEE ALSO 788-------- 789linkgit:gittutorial[7], linkgit:gittutorial-2[7], 790link:everyday.html[Everyday Git], linkgit:gitcvs-migration[7], 791linkgit:gitglossary[7], linkgit:gitcore-tutorial[7], 792linkgit:gitcli[7], link:user-manual.html[The Git User's Manual], 793linkgit:gitworkflows[7] 794 795GIT 796--- 797Part of the linkgit:git[1] suite