6 git - the stupid content tracker
12 'git' [--version] [--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]
13 [-p|--paginate|--no-pager] [--no-replace-objects] [--bare]
14 [--git-dir=<path>] [--work-tree=<path>] [--namespace=<name>]
16 [--help] <command> [<args>]
20 Git is a fast, scalable, distributed revision control system with an
21 unusually rich command set that provides both high-level operations
22 and full access to internals.
24 See linkgit:gittutorial[7] to get started, then see
25 link:everyday.html[Everyday Git] for a useful minimum set of commands, and
26 "man git-commandname" for documentation of each command. CVS users may
27 also want to read linkgit:gitcvs-migration[7]. See
28 the link:user-manual.html[Git User's Manual] for a more in-depth
31 The '<command>' is either a name of a Git command (see below) or an alias
32 as defined in the configuration file (see linkgit:git-config[1]).
34 Formatted and hyperlinked version of the latest git
35 documentation can be viewed at
36 `http://www.kernel.org/pub/software/scm/git/docs/`.
42 You are reading the documentation for the latest (possibly
43 unreleased) version of git, that is available from 'master'
44 branch of the `git.git` repository.
45 Documentation for older releases are available here:
47 * link:v1.7.6/git.html[documentation for release 1.7.6]
50 link:RelNotes/1.7.6.txt[1.7.6].
52 * link:v1.7.5.4/git.html[documentation for release 1.7.5.4]
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].
61 * link:v1.7.4.5/git.html[documentation for release 1.7.4.5]
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].
71 * link:v1.7.3.5/git.html[documentation for release 1.7.3.5]
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].
81 * link:v1.7.2.5/git.html[documentation for release 1.7.2.5]
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].
91 * link:v1.7.1.4/git.html[documentation for release 1.7.1.4]
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].
100 * link:v1.7.0.9/git.html[documentation for release 1.7.0.9]
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].
114 * link:v1.6.6.3/git.html[documentation for release 1.6.6.3]
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].
122 * link:v1.6.5.9/git.html[documentation for release 1.6.5.9]
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].
136 * link:v1.6.4.5/git.html[documentation for release 1.6.4.5]
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].
146 * link:v1.6.3.4/git.html[documentation for release 1.6.3.4]
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].
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].
163 * link:v1.6.1.3/git.html[documentation for release 1.6.1.3]
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].
171 * link:v1.6.0.6/git.html[documentation for release 1.6.0.6]
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].
182 * link:v1.5.6.6/git.html[documentation for release 1.5.6.6]
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].
193 * link:v1.5.5.6/git.html[documentation for release 1.5.5.6]
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].
204 * link:v1.5.4.7/git.html[documentation for release 1.5.4.7]
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].
216 * link:v1.5.3.8/git.html[documentation for release 1.5.3.8]
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].
229 * link:v1.5.2.5/git.html[documentation for release 1.5.2.5]
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].
239 * link:v1.5.1.6/git.html[documentation for release 1.5.1.6]
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].
250 * link:v1.5.0.7/git.html[documentation for release 1.5.0.7]
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].
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].
273 Prints the git suite version that the 'git' program came from.
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.
281 Other options are available to control how the manual page is
282 displayed. See linkgit:git-help[1] for more information,
283 because `git --help ...` is converted internally into `git
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).
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.
299 Print the path, without trailing slash, where git's HTML
300 documentation is installed and exit.
303 Print the manpath (see `man(1)`) for the man pages for
304 this version of git and exit.
307 Print the path where the Info files documenting this
308 version of git are installed and exit.
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
318 Do not pipe git output into a pager.
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.
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).
334 Set the git namespace. See linkgit:gitnamespaces[7] for more
335 details. Equivalent to setting the `GIT_NAMESPACE` environment
339 Treat the repository as a bare repository. If GIT_DIR
340 environment is not set, it is set to the current working
343 --no-replace-objects::
344 Do not use replacement refs to replace git objects. See
345 linkgit:git-replace[1] for more information.
348 FURTHER DOCUMENTATION
349 ---------------------
351 See the references above to get started using git. The following is
352 probably more detail than necessary for a first-time user.
354 The link:user-manual.html#git-concepts[git concepts chapter of the
355 user-manual] and linkgit:gitcore-tutorial[7] both provide
356 introductions to the underlying git architecture.
358 See linkgit:gitworkflows[7] for an overview of recommended workflows.
360 See also the link:howto-index.html[howto] documents for some useful
363 The internals are documented in the
364 link:technical/api-index.html[GIT API documentation].
369 We divide git into high level ("porcelain") commands and low level
370 ("plumbing") commands.
372 High-level commands (porcelain)
373 -------------------------------
375 We separate the porcelain commands into the main commands and some
376 ancillary user utilities.
378 Main porcelain commands
379 ~~~~~~~~~~~~~~~~~~~~~~~
381 include::cmds-mainporcelain.txt[]
387 include::cmds-ancillarymanipulators.txt[]
391 include::cmds-ancillaryinterrogators.txt[]
394 Interacting with Others
395 ~~~~~~~~~~~~~~~~~~~~~~~
397 These commands are to interact with foreign SCM and with other
398 people via patch over e-mail.
400 include::cmds-foreignscminterface.txt[]
403 Low-level commands (plumbing)
404 -----------------------------
406 Although git includes its
407 own porcelain layer, its low-level commands are sufficient to support
408 development of alternative porcelains. Developers of such porcelains
409 might start by reading about linkgit:git-update-index[1] and
410 linkgit:git-read-tree[1].
412 The interface (input, output, set of options and the semantics)
413 to these low-level commands are meant to be a lot more stable
414 than Porcelain level commands, because these commands are
415 primarily for scripted use. The interface to Porcelain commands
416 on the other hand are subject to change in order to improve the
419 The following description divides
420 the low-level commands into commands that manipulate objects (in
421 the repository, index, and working tree), commands that interrogate and
422 compare objects, and commands that move objects and references between
426 Manipulation commands
427 ~~~~~~~~~~~~~~~~~~~~~
429 include::cmds-plumbingmanipulators.txt[]
432 Interrogation commands
433 ~~~~~~~~~~~~~~~~~~~~~~
435 include::cmds-plumbinginterrogators.txt[]
437 In general, the interrogate commands do not touch the files in
441 Synching repositories
442 ~~~~~~~~~~~~~~~~~~~~~
444 include::cmds-synchingrepositories.txt[]
446 The following are helper commands used by the above; end users
447 typically do not use them directly.
449 include::cmds-synchelpers.txt[]
452 Internal helper commands
453 ~~~~~~~~~~~~~~~~~~~~~~~~
455 These are internal helper commands used by other commands; end
456 users typically do not use them directly.
458 include::cmds-purehelpers.txt[]
461 Configuration Mechanism
462 -----------------------
464 Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file
465 is used to hold per-repository configuration options. It is a
466 simple text file modeled after `.ini` format familiar to some
467 people. Here is an example:
471 # A '#' or ';' character indicates a comment.
476 ; Don't trust file modes
481 name = "Junio C Hamano"
482 email = "junkio@twinsun.com"
486 Various commands read from the configuration file and adjust
487 their operation accordingly. See linkgit:git-config[1] for a
491 Identifier Terminology
492 ----------------------
494 Indicates the object name for any type of object.
497 Indicates a blob object name.
500 Indicates a tree object name.
503 Indicates a commit object name.
506 Indicates a tree, commit or tag object name. A
507 command that takes a <tree-ish> argument ultimately wants to
508 operate on a <tree> object but automatically dereferences
509 <commit> and <tag> objects that point at a <tree>.
512 Indicates a commit or tag object name. A
513 command that takes a <commit-ish> argument ultimately wants to
514 operate on a <commit> object but automatically dereferences
515 <tag> objects that point at a <commit>.
518 Indicates that an object type is required.
519 Currently one of: `blob`, `tree`, `commit`, or `tag`.
522 Indicates a filename - almost always relative to the
523 root of the tree structure `GIT_INDEX_FILE` describes.
527 Any git command accepting any <object> can also use the following
531 indicates the head of the current branch.
535 (i.e. a `refs/tags/<tag>` reference).
539 (i.e. a `refs/heads/<head>` reference).
541 For a more complete list of ways to spell object names, see
542 "SPECIFYING REVISIONS" section in linkgit:gitrevisions[7].
545 File/Directory Structure
546 ------------------------
548 Please see the linkgit:gitrepository-layout[5] document.
550 Read linkgit:githooks[5] for more details about each hook.
552 Higher level SCMs may provide and manage additional information in the
558 Please see linkgit:gitglossary[7].
561 Environment Variables
562 ---------------------
563 Various git commands use the following environment variables:
567 These environment variables apply to 'all' core git commands. Nb: it
568 is worth noting that they may be used/overridden by SCMS sitting above
569 git so take care if using Cogito etc.
572 This environment allows the specification of an alternate
573 index file. If not specified, the default of `$GIT_DIR/index`
576 'GIT_OBJECT_DIRECTORY'::
577 If the object storage directory is specified via this
578 environment variable then the sha1 directories are created
579 underneath - otherwise the default `$GIT_DIR/objects`
582 'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
583 Due to the immutable nature of git objects, old objects can be
584 archived into shared, read-only directories. This variable
585 specifies a ":" separated (on Windows ";" separated) list
586 of git object directories which can be used to search for git
587 objects. New objects will not be written to these directories.
590 If the 'GIT_DIR' environment variable is set then it
591 specifies a path to use instead of the default `.git`
592 for the base of the repository.
595 Set the path to the working tree. The value will not be
596 used in combination with repositories found automatically in
597 a .git directory (i.e. $GIT_DIR is not set).
598 This can also be controlled by the '--work-tree' command line
599 option and the core.worktree configuration variable.
602 Set the git namespace; see linkgit:gitnamespaces[7] for details.
603 The '--namespace' command-line option also sets this value.
605 'GIT_CEILING_DIRECTORIES'::
606 This should be a colon-separated list of absolute paths.
607 If set, it is a list of directories that git should not chdir
608 up into while looking for a repository directory.
609 It will not exclude the current working directory or
610 a GIT_DIR set on the command line or in the environment.
611 (Useful for excluding slow-loading network directories.)
613 'GIT_DISCOVERY_ACROSS_FILESYSTEM'::
614 When run in a directory that does not have ".git" repository
615 directory, git tries to find such a directory in the parent
616 directories to find the top of the working tree, but by default it
617 does not cross filesystem boundaries. This environment variable
618 can be set to true to tell git not to stop at filesystem
619 boundaries. Like 'GIT_CEILING_DIRECTORIES', this will not affect
620 an explicit repository directory set via 'GIT_DIR' or on the
628 'GIT_COMMITTER_NAME'::
629 'GIT_COMMITTER_EMAIL'::
630 'GIT_COMMITTER_DATE'::
632 see linkgit:git-commit-tree[1]
637 Only valid setting is "--unified=??" or "-u??" to set the
638 number of context lines shown when a unified diff is created.
639 This takes precedence over any "-U" or "--unified" option
640 value passed on the git diff command line.
642 'GIT_EXTERNAL_DIFF'::
643 When the environment variable 'GIT_EXTERNAL_DIFF' is set, the
644 program named by it is called, instead of the diff invocation
645 described above. For a path that is added, removed, or modified,
646 'GIT_EXTERNAL_DIFF' is called with 7 parameters:
648 path old-file old-hex old-mode new-file new-hex new-mode
652 <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the
653 contents of <old|new>,
654 <old|new>-hex:: are the 40-hexdigit SHA1 hashes,
655 <old|new>-mode:: are the octal representation of the file modes.
657 The file parameters can point at the user's working file
658 (e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
659 when a new file is added), or a temporary file (e.g. `old-file` in the
660 index). 'GIT_EXTERNAL_DIFF' should not worry about unlinking the
661 temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits.
663 For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1
668 'GIT_MERGE_VERBOSITY'::
669 A number controlling the amount of output shown by
670 the recursive merge strategy. Overrides merge.verbosity.
671 See linkgit:git-merge[1]
674 This environment variable overrides `$PAGER`. If it is set
675 to an empty string or to the value "cat", git will not launch
676 a pager. See also the `core.pager` option in
677 linkgit:git-config[1].
680 If this environment variable is set then 'git fetch'
681 and 'git push' will use this command instead
682 of 'ssh' when they need to connect to a remote system.
683 The '$GIT_SSH' command will be given exactly two arguments:
684 the 'username@host' (or just 'host') from the URL and the
685 shell command to execute on that remote system.
687 To pass options to the program that you want to list in GIT_SSH
688 you will need to wrap the program and options into a shell script,
689 then set GIT_SSH to refer to the shell script.
691 Usually it is easier to configure any desired options through your
692 personal `.ssh/config` file. Please consult your ssh documentation
696 If this environment variable is set, then git commands which need to
697 acquire passwords or passphrases (e.g. for HTTP or IMAP authentication)
698 will call this program with a suitable prompt as command line argument
699 and read the password from its STDOUT. See also the 'core.askpass'
700 option in linkgit:git-config[1].
703 If this environment variable is set to "1", then commands such
704 as 'git blame' (in incremental mode), 'git rev-list', 'git log',
705 and 'git whatchanged' will force a flush of the output stream
706 after each commit-oriented record have been flushed. If this
707 variable is set to "0", the output of these commands will be done
708 using completely buffered I/O. If this environment variable is
709 not set, git will choose buffered or record-oriented flushing
710 based on whether stdout appears to be redirected to a file or not.
713 If this variable is set to "1", "2" or "true" (comparison
714 is case insensitive), git will print `trace:` messages on
715 stderr telling about alias expansion, built-in command
716 execution and external command execution.
717 If this variable is set to an integer value greater than 1
718 and lower than 10 (strictly) then git will interpret this
719 value as an open file descriptor and will try to write the
720 trace messages into this file descriptor.
721 Alternatively, if this variable is set to an absolute path
722 (starting with a '/' character), git will interpret this
723 as a file path and will try to write the trace messages
726 Discussion[[Discussion]]
727 ------------------------
729 More detail on the following is available from the
730 link:user-manual.html#git-concepts[git concepts chapter of the
731 user-manual] and linkgit:gitcore-tutorial[7].
733 A git project normally consists of a working directory with a ".git"
734 subdirectory at the top level. The .git directory contains, among other
735 things, a compressed object database representing the complete history
736 of the project, an "index" file which links that history to the current
737 contents of the working tree, and named pointers into that history such
738 as tags and branch heads.
740 The object database contains objects of three main types: blobs, which
741 hold file data; trees, which point to blobs and other trees to build up
742 directory hierarchies; and commits, which each reference a single tree
743 and some number of parent commits.
745 The commit, equivalent to what other systems call a "changeset" or
746 "version", represents a step in the project's history, and each parent
747 represents an immediately preceding step. Commits with more than one
748 parent represent merges of independent lines of development.
750 All objects are named by the SHA1 hash of their contents, normally
751 written as a string of 40 hex digits. Such names are globally unique.
752 The entire history leading up to a commit can be vouched for by signing
753 just that commit. A fourth object type, the tag, is provided for this
756 When first created, objects are stored in individual files, but for
757 efficiency may later be compressed together into "pack files".
759 Named pointers called refs mark interesting points in history. A ref
760 may contain the SHA1 name of an object or the name of another ref. Refs
761 with names beginning `ref/head/` contain the SHA1 name of the most
762 recent commit (or "head") of a branch under development. SHA1 names of
763 tags of interest are stored under `ref/tags/`. A special ref named
764 `HEAD` contains the name of the currently checked-out branch.
766 The index file is initialized with a list of all paths and, for each
767 path, a blob object and a set of attributes. The blob object represents
768 the contents of the file as of the head of the current branch. The
769 attributes (last modified time, size, etc.) are taken from the
770 corresponding file in the working tree. Subsequent changes to the
771 working tree can be found by comparing these attributes. The index may
772 be updated with new content, and new commits may be created from the
773 content stored in the index.
775 The index is also capable of storing multiple entries (called "stages")
776 for a given pathname. These stages are used to hold the various
777 unmerged version of a file when a merge is in progress.
781 Git was started by Linus Torvalds, and is currently maintained by Junio
782 C Hamano. Numerous contributions have come from the git mailing list
783 <git@vger.kernel.org>. For a more complete list of contributors, see
784 http://git-scm.com/about. If you have a clone of git.git itself, the
785 output of linkgit:git-shortlog[1] and linkgit:git-blame[1] can show you
786 the authors for specific parts of the project.
791 Report bugs to the Git mailing list <git@vger.kernel.org> where the
792 development and maintenance is primarily done. You do not have to be
793 subscribed to the list to send a message there.
797 linkgit:gittutorial[7], linkgit:gittutorial-2[7],
798 link:everyday.html[Everyday Git], linkgit:gitcvs-migration[7],
799 linkgit:gitglossary[7], linkgit:gitcore-tutorial[7],
800 linkgit:gitcli[7], link:user-manual.html[The Git User's Manual],
801 linkgit:gitworkflows[7]
805 Part of the linkgit:git[1] suite