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]
14 [--bare] [--git-dir=<path>] [--work-tree=<path>]
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:v1.7.5.2/git.html[documentation for release 1.7.5.2]
50 link:RelNotes/1.7.5.2.txt[1.7.5.2],
51 link:RelNotes/1.7.5.1.txt[1.7.5.1],
52 link:RelNotes/1.7.5.txt[1.7.5].
54 * link:v1.7.4.5/git.html[documentation for release 1.7.4.5]
57 link:RelNotes/1.7.4.5.txt[1.7.4.5],
58 link:RelNotes/1.7.4.4.txt[1.7.4.4],
59 link:RelNotes/1.7.4.3.txt[1.7.4.3],
60 link:RelNotes/1.7.4.2.txt[1.7.4.2],
61 link:RelNotes/1.7.4.1.txt[1.7.4.1],
62 link:RelNotes/1.7.4.txt[1.7.4].
64 * link:v1.7.3.5/git.html[documentation for release 1.7.3.5]
67 link:RelNotes/1.7.3.5.txt[1.7.3.5],
68 link:RelNotes/1.7.3.4.txt[1.7.3.4],
69 link:RelNotes/1.7.3.3.txt[1.7.3.3],
70 link:RelNotes/1.7.3.2.txt[1.7.3.2],
71 link:RelNotes/1.7.3.1.txt[1.7.3.1],
72 link:RelNotes/1.7.3.txt[1.7.3].
74 * link:v1.7.2.5/git.html[documentation for release 1.7.2.5]
77 link:RelNotes/1.7.2.5.txt[1.7.2.5],
78 link:RelNotes/1.7.2.4.txt[1.7.2.4],
79 link:RelNotes/1.7.2.3.txt[1.7.2.3],
80 link:RelNotes/1.7.2.2.txt[1.7.2.2],
81 link:RelNotes/1.7.2.1.txt[1.7.2.1],
82 link:RelNotes/1.7.2.txt[1.7.2].
84 * link:v1.7.1.4/git.html[documentation for release 1.7.1.4]
87 link:RelNotes/1.7.1.4.txt[1.7.1.4],
88 link:RelNotes/1.7.1.3.txt[1.7.1.3],
89 link:RelNotes/1.7.1.2.txt[1.7.1.2],
90 link:RelNotes/1.7.1.1.txt[1.7.1.1],
91 link:RelNotes/1.7.1.txt[1.7.1].
93 * link:v1.7.0.9/git.html[documentation for release 1.7.0.9]
96 link:RelNotes/1.7.0.9.txt[1.7.0.9],
97 link:RelNotes/1.7.0.8.txt[1.7.0.8],
98 link:RelNotes/1.7.0.7.txt[1.7.0.7],
99 link:RelNotes/1.7.0.6.txt[1.7.0.6],
100 link:RelNotes/1.7.0.5.txt[1.7.0.5],
101 link:RelNotes/1.7.0.4.txt[1.7.0.4],
102 link:RelNotes/1.7.0.3.txt[1.7.0.3],
103 link:RelNotes/1.7.0.2.txt[1.7.0.2],
104 link:RelNotes/1.7.0.1.txt[1.7.0.1],
105 link:RelNotes/1.7.0.txt[1.7.0].
107 * link:v1.6.6.3/git.html[documentation for release 1.6.6.3]
110 link:RelNotes/1.6.6.3.txt[1.6.6.3],
111 link:RelNotes/1.6.6.2.txt[1.6.6.2],
112 link:RelNotes/1.6.6.1.txt[1.6.6.1],
113 link:RelNotes/1.6.6.txt[1.6.6].
115 * link:v1.6.5.9/git.html[documentation for release 1.6.5.9]
118 link:RelNotes/1.6.5.9.txt[1.6.5.9],
119 link:RelNotes/1.6.5.8.txt[1.6.5.8],
120 link:RelNotes/1.6.5.7.txt[1.6.5.7],
121 link:RelNotes/1.6.5.6.txt[1.6.5.6],
122 link:RelNotes/1.6.5.5.txt[1.6.5.5],
123 link:RelNotes/1.6.5.4.txt[1.6.5.4],
124 link:RelNotes/1.6.5.3.txt[1.6.5.3],
125 link:RelNotes/1.6.5.2.txt[1.6.5.2],
126 link:RelNotes/1.6.5.1.txt[1.6.5.1],
127 link:RelNotes/1.6.5.txt[1.6.5].
129 * link:v1.6.4.5/git.html[documentation for release 1.6.4.5]
132 link:RelNotes/1.6.4.5.txt[1.6.4.5],
133 link:RelNotes/1.6.4.4.txt[1.6.4.4],
134 link:RelNotes/1.6.4.3.txt[1.6.4.3],
135 link:RelNotes/1.6.4.2.txt[1.6.4.2],
136 link:RelNotes/1.6.4.1.txt[1.6.4.1],
137 link:RelNotes/1.6.4.txt[1.6.4].
139 * link:v1.6.3.4/git.html[documentation for release 1.6.3.4]
142 link:RelNotes/1.6.3.4.txt[1.6.3.4],
143 link:RelNotes/1.6.3.3.txt[1.6.3.3],
144 link:RelNotes/1.6.3.2.txt[1.6.3.2],
145 link:RelNotes/1.6.3.1.txt[1.6.3.1],
146 link:RelNotes/1.6.3.txt[1.6.3].
149 link:RelNotes/1.6.2.5.txt[1.6.2.5],
150 link:RelNotes/1.6.2.4.txt[1.6.2.4],
151 link:RelNotes/1.6.2.3.txt[1.6.2.3],
152 link:RelNotes/1.6.2.2.txt[1.6.2.2],
153 link:RelNotes/1.6.2.1.txt[1.6.2.1],
154 link:RelNotes/1.6.2.txt[1.6.2].
156 * link:v1.6.1.3/git.html[documentation for release 1.6.1.3]
159 link:RelNotes/1.6.1.3.txt[1.6.1.3],
160 link:RelNotes/1.6.1.2.txt[1.6.1.2],
161 link:RelNotes/1.6.1.1.txt[1.6.1.1],
162 link:RelNotes/1.6.1.txt[1.6.1].
164 * link:v1.6.0.6/git.html[documentation for release 1.6.0.6]
167 link:RelNotes/1.6.0.6.txt[1.6.0.6],
168 link:RelNotes/1.6.0.5.txt[1.6.0.5],
169 link:RelNotes/1.6.0.4.txt[1.6.0.4],
170 link:RelNotes/1.6.0.3.txt[1.6.0.3],
171 link:RelNotes/1.6.0.2.txt[1.6.0.2],
172 link:RelNotes/1.6.0.1.txt[1.6.0.1],
173 link:RelNotes/1.6.0.txt[1.6.0].
175 * link:v1.5.6.6/git.html[documentation for release 1.5.6.6]
178 link:RelNotes/1.5.6.6.txt[1.5.6.6],
179 link:RelNotes/1.5.6.5.txt[1.5.6.5],
180 link:RelNotes/1.5.6.4.txt[1.5.6.4],
181 link:RelNotes/1.5.6.3.txt[1.5.6.3],
182 link:RelNotes/1.5.6.2.txt[1.5.6.2],
183 link:RelNotes/1.5.6.1.txt[1.5.6.1],
184 link:RelNotes/1.5.6.txt[1.5.6].
186 * link:v1.5.5.6/git.html[documentation for release 1.5.5.6]
189 link:RelNotes/1.5.5.6.txt[1.5.5.6],
190 link:RelNotes/1.5.5.5.txt[1.5.5.5],
191 link:RelNotes/1.5.5.4.txt[1.5.5.4],
192 link:RelNotes/1.5.5.3.txt[1.5.5.3],
193 link:RelNotes/1.5.5.2.txt[1.5.5.2],
194 link:RelNotes/1.5.5.1.txt[1.5.5.1],
195 link:RelNotes/1.5.5.txt[1.5.5].
197 * link:v1.5.4.7/git.html[documentation for release 1.5.4.7]
200 link:RelNotes/1.5.4.7.txt[1.5.4.7],
201 link:RelNotes/1.5.4.6.txt[1.5.4.6],
202 link:RelNotes/1.5.4.5.txt[1.5.4.5],
203 link:RelNotes/1.5.4.4.txt[1.5.4.4],
204 link:RelNotes/1.5.4.3.txt[1.5.4.3],
205 link:RelNotes/1.5.4.2.txt[1.5.4.2],
206 link:RelNotes/1.5.4.1.txt[1.5.4.1],
207 link:RelNotes/1.5.4.txt[1.5.4].
209 * link:v1.5.3.8/git.html[documentation for release 1.5.3.8]
212 link:RelNotes/1.5.3.8.txt[1.5.3.8],
213 link:RelNotes/1.5.3.7.txt[1.5.3.7],
214 link:RelNotes/1.5.3.6.txt[1.5.3.6],
215 link:RelNotes/1.5.3.5.txt[1.5.3.5],
216 link:RelNotes/1.5.3.4.txt[1.5.3.4],
217 link:RelNotes/1.5.3.3.txt[1.5.3.3],
218 link:RelNotes/1.5.3.2.txt[1.5.3.2],
219 link:RelNotes/1.5.3.1.txt[1.5.3.1],
220 link:RelNotes/1.5.3.txt[1.5.3].
222 * link:v1.5.2.5/git.html[documentation for release 1.5.2.5]
225 link:RelNotes/1.5.2.5.txt[1.5.2.5],
226 link:RelNotes/1.5.2.4.txt[1.5.2.4],
227 link:RelNotes/1.5.2.3.txt[1.5.2.3],
228 link:RelNotes/1.5.2.2.txt[1.5.2.2],
229 link:RelNotes/1.5.2.1.txt[1.5.2.1],
230 link:RelNotes/1.5.2.txt[1.5.2].
232 * link:v1.5.1.6/git.html[documentation for release 1.5.1.6]
235 link:RelNotes/1.5.1.6.txt[1.5.1.6],
236 link:RelNotes/1.5.1.5.txt[1.5.1.5],
237 link:RelNotes/1.5.1.4.txt[1.5.1.4],
238 link:RelNotes/1.5.1.3.txt[1.5.1.3],
239 link:RelNotes/1.5.1.2.txt[1.5.1.2],
240 link:RelNotes/1.5.1.1.txt[1.5.1.1],
241 link:RelNotes/1.5.1.txt[1.5.1].
243 * link:v1.5.0.7/git.html[documentation for release 1.5.0.7]
246 link:RelNotes/1.5.0.7.txt[1.5.0.7],
247 link:RelNotes/1.5.0.6.txt[1.5.0.6],
248 link:RelNotes/1.5.0.5.txt[1.5.0.5],
249 link:RelNotes/1.5.0.3.txt[1.5.0.3],
250 link:RelNotes/1.5.0.2.txt[1.5.0.2],
251 link:RelNotes/1.5.0.1.txt[1.5.0.1],
252 link:RelNotes/1.5.0.txt[1.5.0].
254 * documentation for release link:v1.4.4.4/git.html[1.4.4.4],
255 link:v1.3.3/git.html[1.3.3],
256 link:v1.2.6/git.html[1.2.6],
257 link:v1.0.13/git.html[1.0.13].
266 Prints the git suite version that the 'git' program came from.
269 Prints the synopsis and a list of the most commonly used
270 commands. If the option '--all' or '-a' is given then all
271 available commands are printed. If a git command is named this
272 option will bring up the manual page for that command.
274 Other options are available to control how the manual page is
275 displayed. See linkgit:git-help[1] for more information,
276 because `git --help ...` is converted internally into `git
280 Pass a configuration parameter to the command. The value
281 given will override values from configuration files.
282 The <name> is expected in the same format as listed by
283 'git config' (subkeys separated by dots).
285 --exec-path[=<path>]::
286 Path to wherever your core git programs are installed.
287 This can also be controlled by setting the GIT_EXEC_PATH
288 environment variable. If no path is given, 'git' will print
289 the current setting and then exit.
292 Print the path, without trailing slash, where git's HTML
293 documentation is installed and exit.
296 Print the manpath (see `man(1)`) for the man pages for
297 this version of git and exit.
300 Print the path where the Info files documenting this
301 version of git are installed and exit.
305 Pipe all output into 'less' (or if set, $PAGER) if standard
306 output is a terminal. This overrides the `pager.<cmd>`
307 configuration options (see the "Configuration Mechanism" section
311 Do not pipe git output into a pager.
314 Set the path to the repository. This can also be controlled by
315 setting the GIT_DIR environment variable. It can be an absolute
316 path or relative path to current working directory.
319 Set the path to the working tree. It can be an absolute path
320 or a path relative to the current working directory.
321 This can also be controlled by setting the GIT_WORK_TREE
322 environment variable and the core.worktree configuration
323 variable (see core.worktree in linkgit:git-config[1] for a
324 more detailed discussion).
327 Treat the repository as a bare repository. If GIT_DIR
328 environment is not set, it is set to the current working
331 --no-replace-objects::
332 Do not use replacement refs to replace git objects. See
333 linkgit:git-replace[1] for more information.
336 FURTHER DOCUMENTATION
337 ---------------------
339 See the references above to get started using git. The following is
340 probably more detail than necessary for a first-time user.
342 The link:user-manual.html#git-concepts[git concepts chapter of the
343 user-manual] and linkgit:gitcore-tutorial[7] both provide
344 introductions to the underlying git architecture.
346 See linkgit:gitworkflows[7] for an overview of recommended workflows.
348 See also the link:howto-index.html[howto] documents for some useful
351 The internals are documented in the
352 link:technical/api-index.html[GIT API documentation].
357 We divide git into high level ("porcelain") commands and low level
358 ("plumbing") commands.
360 High-level commands (porcelain)
361 -------------------------------
363 We separate the porcelain commands into the main commands and some
364 ancillary user utilities.
366 Main porcelain commands
367 ~~~~~~~~~~~~~~~~~~~~~~~
369 include::cmds-mainporcelain.txt[]
375 include::cmds-ancillarymanipulators.txt[]
379 include::cmds-ancillaryinterrogators.txt[]
382 Interacting with Others
383 ~~~~~~~~~~~~~~~~~~~~~~~
385 These commands are to interact with foreign SCM and with other
386 people via patch over e-mail.
388 include::cmds-foreignscminterface.txt[]
391 Low-level commands (plumbing)
392 -----------------------------
394 Although git includes its
395 own porcelain layer, its low-level commands are sufficient to support
396 development of alternative porcelains. Developers of such porcelains
397 might start by reading about linkgit:git-update-index[1] and
398 linkgit:git-read-tree[1].
400 The interface (input, output, set of options and the semantics)
401 to these low-level commands are meant to be a lot more stable
402 than Porcelain level commands, because these commands are
403 primarily for scripted use. The interface to Porcelain commands
404 on the other hand are subject to change in order to improve the
407 The following description divides
408 the low-level commands into commands that manipulate objects (in
409 the repository, index, and working tree), commands that interrogate and
410 compare objects, and commands that move objects and references between
414 Manipulation commands
415 ~~~~~~~~~~~~~~~~~~~~~
417 include::cmds-plumbingmanipulators.txt[]
420 Interrogation commands
421 ~~~~~~~~~~~~~~~~~~~~~~
423 include::cmds-plumbinginterrogators.txt[]
425 In general, the interrogate commands do not touch the files in
429 Synching repositories
430 ~~~~~~~~~~~~~~~~~~~~~
432 include::cmds-synchingrepositories.txt[]
434 The following are helper commands used by the above; end users
435 typically do not use them directly.
437 include::cmds-synchelpers.txt[]
440 Internal helper commands
441 ~~~~~~~~~~~~~~~~~~~~~~~~
443 These are internal helper commands used by other commands; end
444 users typically do not use them directly.
446 include::cmds-purehelpers.txt[]
449 Configuration Mechanism
450 -----------------------
452 Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file
453 is used to hold per-repository configuration options. It is a
454 simple text file modeled after `.ini` format familiar to some
455 people. Here is an example:
459 # A '#' or ';' character indicates a comment.
464 ; Don't trust file modes
469 name = "Junio C Hamano"
470 email = "junkio@twinsun.com"
474 Various commands read from the configuration file and adjust
475 their operation accordingly. See linkgit:git-config[1] for a
479 Identifier Terminology
480 ----------------------
482 Indicates the object name for any type of object.
485 Indicates a blob object name.
488 Indicates a tree object name.
491 Indicates a commit object name.
494 Indicates a tree, commit or tag object name. A
495 command that takes a <tree-ish> argument ultimately wants to
496 operate on a <tree> object but automatically dereferences
497 <commit> and <tag> objects that point at a <tree>.
500 Indicates a commit or tag object name. A
501 command that takes a <commit-ish> argument ultimately wants to
502 operate on a <commit> object but automatically dereferences
503 <tag> objects that point at a <commit>.
506 Indicates that an object type is required.
507 Currently one of: `blob`, `tree`, `commit`, or `tag`.
510 Indicates a filename - almost always relative to the
511 root of the tree structure `GIT_INDEX_FILE` describes.
515 Any git command accepting any <object> can also use the following
519 indicates the head of the current branch (i.e. the
520 contents of `$GIT_DIR/HEAD`).
524 (i.e. the contents of `$GIT_DIR/refs/tags/<tag>`).
528 (i.e. the contents of `$GIT_DIR/refs/heads/<head>`).
530 For a more complete list of ways to spell object names, see
531 "SPECIFYING REVISIONS" section in linkgit:gitrevisions[7].
534 File/Directory Structure
535 ------------------------
537 Please see the linkgit:gitrepository-layout[5] document.
539 Read linkgit:githooks[5] for more details about each hook.
541 Higher level SCMs may provide and manage additional information in the
547 Please see linkgit:gitglossary[7].
550 Environment Variables
551 ---------------------
552 Various git commands use the following environment variables:
556 These environment variables apply to 'all' core git commands. Nb: it
557 is worth noting that they may be used/overridden by SCMS sitting above
558 git so take care if using Cogito etc.
561 This environment allows the specification of an alternate
562 index file. If not specified, the default of `$GIT_DIR/index`
565 'GIT_OBJECT_DIRECTORY'::
566 If the object storage directory is specified via this
567 environment variable then the sha1 directories are created
568 underneath - otherwise the default `$GIT_DIR/objects`
571 'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
572 Due to the immutable nature of git objects, old objects can be
573 archived into shared, read-only directories. This variable
574 specifies a ":" separated (on Windows ";" separated) list
575 of git object directories which can be used to search for git
576 objects. New objects will not be written to these directories.
579 If the 'GIT_DIR' environment variable is set then it
580 specifies a path to use instead of the default `.git`
581 for the base of the repository.
584 Set the path to the working tree. The value will not be
585 used in combination with repositories found automatically in
586 a .git directory (i.e. $GIT_DIR is not set).
587 This can also be controlled by the '--work-tree' command line
588 option and the core.worktree configuration variable.
590 'GIT_CEILING_DIRECTORIES'::
591 This should be a colon-separated list of absolute paths.
592 If set, it is a list of directories that git should not chdir
593 up into while looking for a repository directory.
594 It will not exclude the current working directory or
595 a GIT_DIR set on the command line or in the environment.
596 (Useful for excluding slow-loading network directories.)
598 'GIT_DISCOVERY_ACROSS_FILESYSTEM'::
599 When run in a directory that does not have ".git" repository
600 directory, git tries to find such a directory in the parent
601 directories to find the top of the working tree, but by default it
602 does not cross filesystem boundaries. This environment variable
603 can be set to true to tell git not to stop at filesystem
604 boundaries. Like 'GIT_CEILING_DIRECTORIES', this will not affect
605 an explicit repository directory set via 'GIT_DIR' or on the
613 'GIT_COMMITTER_NAME'::
614 'GIT_COMMITTER_EMAIL'::
615 'GIT_COMMITTER_DATE'::
617 see linkgit:git-commit-tree[1]
622 Only valid setting is "--unified=??" or "-u??" to set the
623 number of context lines shown when a unified diff is created.
624 This takes precedence over any "-U" or "--unified" option
625 value passed on the git diff command line.
627 'GIT_EXTERNAL_DIFF'::
628 When the environment variable 'GIT_EXTERNAL_DIFF' is set, the
629 program named by it is called, instead of the diff invocation
630 described above. For a path that is added, removed, or modified,
631 'GIT_EXTERNAL_DIFF' is called with 7 parameters:
633 path old-file old-hex old-mode new-file new-hex new-mode
637 <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the
638 contents of <old|new>,
639 <old|new>-hex:: are the 40-hexdigit SHA1 hashes,
640 <old|new>-mode:: are the octal representation of the file modes.
642 The file parameters can point at the user's working file
643 (e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
644 when a new file is added), or a temporary file (e.g. `old-file` in the
645 index). 'GIT_EXTERNAL_DIFF' should not worry about unlinking the
646 temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits.
648 For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1
653 'GIT_MERGE_VERBOSITY'::
654 A number controlling the amount of output shown by
655 the recursive merge strategy. Overrides merge.verbosity.
656 See linkgit:git-merge[1]
659 This environment variable overrides `$PAGER`. If it is set
660 to an empty string or to the value "cat", git will not launch
661 a pager. See also the `core.pager` option in
662 linkgit:git-config[1].
665 If this environment variable is set then 'git fetch'
666 and 'git push' will use this command instead
667 of 'ssh' when they need to connect to a remote system.
668 The '$GIT_SSH' command will be given exactly two arguments:
669 the 'username@host' (or just 'host') from the URL and the
670 shell command to execute on that remote system.
672 To pass options to the program that you want to list in GIT_SSH
673 you will need to wrap the program and options into a shell script,
674 then set GIT_SSH to refer to the shell script.
676 Usually it is easier to configure any desired options through your
677 personal `.ssh/config` file. Please consult your ssh documentation
681 If this environment variable is set, then git commands which need to
682 acquire passwords or passphrases (e.g. for HTTP or IMAP authentication)
683 will call this program with a suitable prompt as command line argument
684 and read the password from its STDOUT. See also the 'core.askpass'
685 option in linkgit:git-config[1].
688 If this environment variable is set to "1", then commands such
689 as 'git blame' (in incremental mode), 'git rev-list', 'git log',
690 and 'git whatchanged' will force a flush of the output stream
691 after each commit-oriented record have been flushed. If this
692 variable is set to "0", the output of these commands will be done
693 using completely buffered I/O. If this environment variable is
694 not set, git will choose buffered or record-oriented flushing
695 based on whether stdout appears to be redirected to a file or not.
698 If this variable is set to "1", "2" or "true" (comparison
699 is case insensitive), git will print `trace:` messages on
700 stderr telling about alias expansion, built-in command
701 execution and external command execution.
702 If this variable is set to an integer value greater than 1
703 and lower than 10 (strictly) then git will interpret this
704 value as an open file descriptor and will try to write the
705 trace messages into this file descriptor.
706 Alternatively, if this variable is set to an absolute path
707 (starting with a '/' character), git will interpret this
708 as a file path and will try to write the trace messages
711 Discussion[[Discussion]]
712 ------------------------
714 More detail on the following is available from the
715 link:user-manual.html#git-concepts[git concepts chapter of the
716 user-manual] and linkgit:gitcore-tutorial[7].
718 A git project normally consists of a working directory with a ".git"
719 subdirectory at the top level. The .git directory contains, among other
720 things, a compressed object database representing the complete history
721 of the project, an "index" file which links that history to the current
722 contents of the working tree, and named pointers into that history such
723 as tags and branch heads.
725 The object database contains objects of three main types: blobs, which
726 hold file data; trees, which point to blobs and other trees to build up
727 directory hierarchies; and commits, which each reference a single tree
728 and some number of parent commits.
730 The commit, equivalent to what other systems call a "changeset" or
731 "version", represents a step in the project's history, and each parent
732 represents an immediately preceding step. Commits with more than one
733 parent represent merges of independent lines of development.
735 All objects are named by the SHA1 hash of their contents, normally
736 written as a string of 40 hex digits. Such names are globally unique.
737 The entire history leading up to a commit can be vouched for by signing
738 just that commit. A fourth object type, the tag, is provided for this
741 When first created, objects are stored in individual files, but for
742 efficiency may later be compressed together into "pack files".
744 Named pointers called refs mark interesting points in history. A ref
745 may contain the SHA1 name of an object or the name of another ref. Refs
746 with names beginning `ref/head/` contain the SHA1 name of the most
747 recent commit (or "head") of a branch under development. SHA1 names of
748 tags of interest are stored under `ref/tags/`. A special ref named
749 `HEAD` contains the name of the currently checked-out branch.
751 The index file is initialized with a list of all paths and, for each
752 path, a blob object and a set of attributes. The blob object represents
753 the contents of the file as of the head of the current branch. The
754 attributes (last modified time, size, etc.) are taken from the
755 corresponding file in the working tree. Subsequent changes to the
756 working tree can be found by comparing these attributes. The index may
757 be updated with new content, and new commits may be created from the
758 content stored in the index.
760 The index is also capable of storing multiple entries (called "stages")
761 for a given pathname. These stages are used to hold the various
762 unmerged version of a file when a merge is in progress.
766 Git was started by Linus Torvalds, and is currently maintained by Junio
767 C Hamano. Numerous contributions have come from the git mailing list
768 <git@vger.kernel.org>. For a more complete list of contributors, see
769 http://git-scm.com/about. If you have a clone of git.git itself, the
770 output of linkgit:git-shortlog[1] and linkgit:git-blame[1] can show you
771 the authors for specific parts of the project.
776 Report bugs to the Git mailing list <git@vger.kernel.org> where the
777 development and maintenance is primarily done. You do not have to be
778 subscribed to the list to send a message there.
782 linkgit:gittutorial[7], linkgit:gittutorial-2[7],
783 link:everyday.html[Everyday Git], linkgit:gitcvs-migration[7],
784 linkgit:gitglossary[7], linkgit:gitcore-tutorial[7],
785 linkgit:gitcli[7], link:user-manual.html[The Git User's Manual],
786 linkgit:gitworkflows[7]
790 Part of the linkgit:git[1] suite