6 git - the stupid content tracker
12 'git' [--version] [--exec-path[=<path>]] [--html-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:v1.7.5.4/git.html[documentation for release 1.7.5.4]
50 link:RelNotes/1.7.5.4.txt[1.7.5.4],
51 link:RelNotes/1.7.5.3.txt[1.7.5.3],
52 link:RelNotes/1.7.5.2.txt[1.7.5.2],
53 link:RelNotes/1.7.5.1.txt[1.7.5.1],
54 link:RelNotes/1.7.5.txt[1.7.5].
56 * link:v1.7.4.5/git.html[documentation for release 1.7.4.5]
59 link:RelNotes/1.7.4.5.txt[1.7.4.5],
60 link:RelNotes/1.7.4.4.txt[1.7.4.4],
61 link:RelNotes/1.7.4.3.txt[1.7.4.3],
62 link:RelNotes/1.7.4.2.txt[1.7.4.2],
63 link:RelNotes/1.7.4.1.txt[1.7.4.1],
64 link:RelNotes/1.7.4.txt[1.7.4].
66 * link:v1.7.3.5/git.html[documentation for release 1.7.3.5]
69 link:RelNotes/1.7.3.5.txt[1.7.3.5],
70 link:RelNotes/1.7.3.4.txt[1.7.3.4],
71 link:RelNotes/1.7.3.3.txt[1.7.3.3],
72 link:RelNotes/1.7.3.2.txt[1.7.3.2],
73 link:RelNotes/1.7.3.1.txt[1.7.3.1],
74 link:RelNotes/1.7.3.txt[1.7.3].
76 * link:v1.7.2.5/git.html[documentation for release 1.7.2.5]
79 link:RelNotes/1.7.2.5.txt[1.7.2.5],
80 link:RelNotes/1.7.2.4.txt[1.7.2.4],
81 link:RelNotes/1.7.2.3.txt[1.7.2.3],
82 link:RelNotes/1.7.2.2.txt[1.7.2.2],
83 link:RelNotes/1.7.2.1.txt[1.7.2.1],
84 link:RelNotes/1.7.2.txt[1.7.2].
86 * link:v1.7.1.4/git.html[documentation for release 1.7.1.4]
89 link:RelNotes/1.7.1.4.txt[1.7.1.4],
90 link:RelNotes/1.7.1.3.txt[1.7.1.3],
91 link:RelNotes/1.7.1.2.txt[1.7.1.2],
92 link:RelNotes/1.7.1.1.txt[1.7.1.1],
93 link:RelNotes/1.7.1.txt[1.7.1].
95 * link:v1.7.0.9/git.html[documentation for release 1.7.0.9]
98 link:RelNotes/1.7.0.9.txt[1.7.0.9],
99 link:RelNotes/1.7.0.8.txt[1.7.0.8],
100 link:RelNotes/1.7.0.7.txt[1.7.0.7],
101 link:RelNotes/1.7.0.6.txt[1.7.0.6],
102 link:RelNotes/1.7.0.5.txt[1.7.0.5],
103 link:RelNotes/1.7.0.4.txt[1.7.0.4],
104 link:RelNotes/1.7.0.3.txt[1.7.0.3],
105 link:RelNotes/1.7.0.2.txt[1.7.0.2],
106 link:RelNotes/1.7.0.1.txt[1.7.0.1],
107 link:RelNotes/1.7.0.txt[1.7.0].
109 * link:v1.6.6.3/git.html[documentation for release 1.6.6.3]
112 link:RelNotes/1.6.6.3.txt[1.6.6.3],
113 link:RelNotes/1.6.6.2.txt[1.6.6.2],
114 link:RelNotes/1.6.6.1.txt[1.6.6.1],
115 link:RelNotes/1.6.6.txt[1.6.6].
117 * link:v1.6.5.9/git.html[documentation for release 1.6.5.9]
120 link:RelNotes/1.6.5.9.txt[1.6.5.9],
121 link:RelNotes/1.6.5.8.txt[1.6.5.8],
122 link:RelNotes/1.6.5.7.txt[1.6.5.7],
123 link:RelNotes/1.6.5.6.txt[1.6.5.6],
124 link:RelNotes/1.6.5.5.txt[1.6.5.5],
125 link:RelNotes/1.6.5.4.txt[1.6.5.4],
126 link:RelNotes/1.6.5.3.txt[1.6.5.3],
127 link:RelNotes/1.6.5.2.txt[1.6.5.2],
128 link:RelNotes/1.6.5.1.txt[1.6.5.1],
129 link:RelNotes/1.6.5.txt[1.6.5].
131 * link:v1.6.4.5/git.html[documentation for release 1.6.4.5]
134 link:RelNotes/1.6.4.5.txt[1.6.4.5],
135 link:RelNotes/1.6.4.4.txt[1.6.4.4],
136 link:RelNotes/1.6.4.3.txt[1.6.4.3],
137 link:RelNotes/1.6.4.2.txt[1.6.4.2],
138 link:RelNotes/1.6.4.1.txt[1.6.4.1],
139 link:RelNotes/1.6.4.txt[1.6.4].
141 * link:v1.6.3.4/git.html[documentation for release 1.6.3.4]
144 link:RelNotes/1.6.3.4.txt[1.6.3.4],
145 link:RelNotes/1.6.3.3.txt[1.6.3.3],
146 link:RelNotes/1.6.3.2.txt[1.6.3.2],
147 link:RelNotes/1.6.3.1.txt[1.6.3.1],
148 link:RelNotes/1.6.3.txt[1.6.3].
151 link:RelNotes/1.6.2.5.txt[1.6.2.5],
152 link:RelNotes/1.6.2.4.txt[1.6.2.4],
153 link:RelNotes/1.6.2.3.txt[1.6.2.3],
154 link:RelNotes/1.6.2.2.txt[1.6.2.2],
155 link:RelNotes/1.6.2.1.txt[1.6.2.1],
156 link:RelNotes/1.6.2.txt[1.6.2].
158 * link:v1.6.1.3/git.html[documentation for release 1.6.1.3]
161 link:RelNotes/1.6.1.3.txt[1.6.1.3],
162 link:RelNotes/1.6.1.2.txt[1.6.1.2],
163 link:RelNotes/1.6.1.1.txt[1.6.1.1],
164 link:RelNotes/1.6.1.txt[1.6.1].
166 * link:v1.6.0.6/git.html[documentation for release 1.6.0.6]
169 link:RelNotes/1.6.0.6.txt[1.6.0.6],
170 link:RelNotes/1.6.0.5.txt[1.6.0.5],
171 link:RelNotes/1.6.0.4.txt[1.6.0.4],
172 link:RelNotes/1.6.0.3.txt[1.6.0.3],
173 link:RelNotes/1.6.0.2.txt[1.6.0.2],
174 link:RelNotes/1.6.0.1.txt[1.6.0.1],
175 link:RelNotes/1.6.0.txt[1.6.0].
177 * link:v1.5.6.6/git.html[documentation for release 1.5.6.6]
180 link:RelNotes/1.5.6.6.txt[1.5.6.6],
181 link:RelNotes/1.5.6.5.txt[1.5.6.5],
182 link:RelNotes/1.5.6.4.txt[1.5.6.4],
183 link:RelNotes/1.5.6.3.txt[1.5.6.3],
184 link:RelNotes/1.5.6.2.txt[1.5.6.2],
185 link:RelNotes/1.5.6.1.txt[1.5.6.1],
186 link:RelNotes/1.5.6.txt[1.5.6].
188 * link:v1.5.5.6/git.html[documentation for release 1.5.5.6]
191 link:RelNotes/1.5.5.6.txt[1.5.5.6],
192 link:RelNotes/1.5.5.5.txt[1.5.5.5],
193 link:RelNotes/1.5.5.4.txt[1.5.5.4],
194 link:RelNotes/1.5.5.3.txt[1.5.5.3],
195 link:RelNotes/1.5.5.2.txt[1.5.5.2],
196 link:RelNotes/1.5.5.1.txt[1.5.5.1],
197 link:RelNotes/1.5.5.txt[1.5.5].
199 * link:v1.5.4.7/git.html[documentation for release 1.5.4.7]
202 link:RelNotes/1.5.4.7.txt[1.5.4.7],
203 link:RelNotes/1.5.4.6.txt[1.5.4.6],
204 link:RelNotes/1.5.4.5.txt[1.5.4.5],
205 link:RelNotes/1.5.4.4.txt[1.5.4.4],
206 link:RelNotes/1.5.4.3.txt[1.5.4.3],
207 link:RelNotes/1.5.4.2.txt[1.5.4.2],
208 link:RelNotes/1.5.4.1.txt[1.5.4.1],
209 link:RelNotes/1.5.4.txt[1.5.4].
211 * link:v1.5.3.8/git.html[documentation for release 1.5.3.8]
214 link:RelNotes/1.5.3.8.txt[1.5.3.8],
215 link:RelNotes/1.5.3.7.txt[1.5.3.7],
216 link:RelNotes/1.5.3.6.txt[1.5.3.6],
217 link:RelNotes/1.5.3.5.txt[1.5.3.5],
218 link:RelNotes/1.5.3.4.txt[1.5.3.4],
219 link:RelNotes/1.5.3.3.txt[1.5.3.3],
220 link:RelNotes/1.5.3.2.txt[1.5.3.2],
221 link:RelNotes/1.5.3.1.txt[1.5.3.1],
222 link:RelNotes/1.5.3.txt[1.5.3].
224 * link:v1.5.2.5/git.html[documentation for release 1.5.2.5]
227 link:RelNotes/1.5.2.5.txt[1.5.2.5],
228 link:RelNotes/1.5.2.4.txt[1.5.2.4],
229 link:RelNotes/1.5.2.3.txt[1.5.2.3],
230 link:RelNotes/1.5.2.2.txt[1.5.2.2],
231 link:RelNotes/1.5.2.1.txt[1.5.2.1],
232 link:RelNotes/1.5.2.txt[1.5.2].
234 * link:v1.5.1.6/git.html[documentation for release 1.5.1.6]
237 link:RelNotes/1.5.1.6.txt[1.5.1.6],
238 link:RelNotes/1.5.1.5.txt[1.5.1.5],
239 link:RelNotes/1.5.1.4.txt[1.5.1.4],
240 link:RelNotes/1.5.1.3.txt[1.5.1.3],
241 link:RelNotes/1.5.1.2.txt[1.5.1.2],
242 link:RelNotes/1.5.1.1.txt[1.5.1.1],
243 link:RelNotes/1.5.1.txt[1.5.1].
245 * link:v1.5.0.7/git.html[documentation for release 1.5.0.7]
248 link:RelNotes/1.5.0.7.txt[1.5.0.7],
249 link:RelNotes/1.5.0.6.txt[1.5.0.6],
250 link:RelNotes/1.5.0.5.txt[1.5.0.5],
251 link:RelNotes/1.5.0.3.txt[1.5.0.3],
252 link:RelNotes/1.5.0.2.txt[1.5.0.2],
253 link:RelNotes/1.5.0.1.txt[1.5.0.1],
254 link:RelNotes/1.5.0.txt[1.5.0].
256 * documentation for release link:v1.4.4.4/git.html[1.4.4.4],
257 link:v1.3.3/git.html[1.3.3],
258 link:v1.2.6/git.html[1.2.6],
259 link:v1.0.13/git.html[1.0.13].
268 Prints the git suite version that the 'git' program came from.
271 Prints the synopsis and a list of the most commonly used
272 commands. If the option '--all' or '-a' is given then all
273 available commands are printed. If a git command is named this
274 option will bring up the manual page for that command.
276 Other options are available to control how the manual page is
277 displayed. See linkgit:git-help[1] for more information,
278 because `git --help ...` is converted internally into `git
282 Pass a configuration parameter to the command. The value
283 given will override values from configuration files.
284 The <name> is expected in the same format as listed by
285 'git config' (subkeys separated by dots).
287 --exec-path[=<path>]::
288 Path to wherever your core git programs are installed.
289 This can also be controlled by setting the GIT_EXEC_PATH
290 environment variable. If no path is given, 'git' will print
291 the current setting and then exit.
294 Print the path to wherever your git HTML documentation is installed
299 Pipe all output into 'less' (or if set, $PAGER) if standard
300 output is a terminal. This overrides the `pager.<cmd>`
301 configuration options (see the "Configuration Mechanism" section
305 Do not pipe git output into a pager.
308 Set the path to the repository. This can also be controlled by
309 setting the GIT_DIR environment variable. It can be an absolute
310 path or relative path to current working directory.
313 Set the path to the working tree. It can be an absolute path
314 or a path relative to the current working directory.
315 This can also be controlled by setting the GIT_WORK_TREE
316 environment variable and the core.worktree configuration
317 variable (see core.worktree in linkgit:git-config[1] for a
318 more detailed discussion).
321 Treat the repository as a bare repository. If GIT_DIR
322 environment is not set, it is set to the current working
325 --no-replace-objects::
326 Do not use replacement refs to replace git objects. See
327 linkgit:git-replace[1] for more information.
330 FURTHER DOCUMENTATION
331 ---------------------
333 See the references above to get started using git. The following is
334 probably more detail than necessary for a first-time user.
336 The link:user-manual.html#git-concepts[git concepts chapter of the
337 user-manual] and linkgit:gitcore-tutorial[7] both provide
338 introductions to the underlying git architecture.
340 See linkgit:gitworkflows[7] for an overview of recommended workflows.
342 See also the link:howto-index.html[howto] documents for some useful
345 The internals are documented in the
346 link:technical/api-index.html[GIT API documentation].
351 We divide git into high level ("porcelain") commands and low level
352 ("plumbing") commands.
354 High-level commands (porcelain)
355 -------------------------------
357 We separate the porcelain commands into the main commands and some
358 ancillary user utilities.
360 Main porcelain commands
361 ~~~~~~~~~~~~~~~~~~~~~~~
363 include::cmds-mainporcelain.txt[]
369 include::cmds-ancillarymanipulators.txt[]
373 include::cmds-ancillaryinterrogators.txt[]
376 Interacting with Others
377 ~~~~~~~~~~~~~~~~~~~~~~~
379 These commands are to interact with foreign SCM and with other
380 people via patch over e-mail.
382 include::cmds-foreignscminterface.txt[]
385 Low-level commands (plumbing)
386 -----------------------------
388 Although git includes its
389 own porcelain layer, its low-level commands are sufficient to support
390 development of alternative porcelains. Developers of such porcelains
391 might start by reading about linkgit:git-update-index[1] and
392 linkgit:git-read-tree[1].
394 The interface (input, output, set of options and the semantics)
395 to these low-level commands are meant to be a lot more stable
396 than Porcelain level commands, because these commands are
397 primarily for scripted use. The interface to Porcelain commands
398 on the other hand are subject to change in order to improve the
401 The following description divides
402 the low-level commands into commands that manipulate objects (in
403 the repository, index, and working tree), commands that interrogate and
404 compare objects, and commands that move objects and references between
408 Manipulation commands
409 ~~~~~~~~~~~~~~~~~~~~~
411 include::cmds-plumbingmanipulators.txt[]
414 Interrogation commands
415 ~~~~~~~~~~~~~~~~~~~~~~
417 include::cmds-plumbinginterrogators.txt[]
419 In general, the interrogate commands do not touch the files in
423 Synching repositories
424 ~~~~~~~~~~~~~~~~~~~~~
426 include::cmds-synchingrepositories.txt[]
428 The following are helper commands used by the above; end users
429 typically do not use them directly.
431 include::cmds-synchelpers.txt[]
434 Internal helper commands
435 ~~~~~~~~~~~~~~~~~~~~~~~~
437 These are internal helper commands used by other commands; end
438 users typically do not use them directly.
440 include::cmds-purehelpers.txt[]
443 Configuration Mechanism
444 -----------------------
446 Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file
447 is used to hold per-repository configuration options. It is a
448 simple text file modeled after `.ini` format familiar to some
449 people. Here is an example:
453 # A '#' or ';' character indicates a comment.
458 ; Don't trust file modes
463 name = "Junio C Hamano"
464 email = "junkio@twinsun.com"
468 Various commands read from the configuration file and adjust
469 their operation accordingly. See linkgit:git-config[1] for a
473 Identifier Terminology
474 ----------------------
476 Indicates the object name for any type of object.
479 Indicates a blob object name.
482 Indicates a tree object name.
485 Indicates a commit object name.
488 Indicates a tree, commit or tag object name. A
489 command that takes a <tree-ish> argument ultimately wants to
490 operate on a <tree> object but automatically dereferences
491 <commit> and <tag> objects that point at a <tree>.
494 Indicates a commit or tag object name. A
495 command that takes a <commit-ish> argument ultimately wants to
496 operate on a <commit> object but automatically dereferences
497 <tag> objects that point at a <commit>.
500 Indicates that an object type is required.
501 Currently one of: `blob`, `tree`, `commit`, or `tag`.
504 Indicates a filename - almost always relative to the
505 root of the tree structure `GIT_INDEX_FILE` describes.
509 Any git command accepting any <object> can also use the following
513 indicates the head of the current branch (i.e. the
514 contents of `$GIT_DIR/HEAD`).
518 (i.e. the contents of `$GIT_DIR/refs/tags/<tag>`).
522 (i.e. the contents of `$GIT_DIR/refs/heads/<head>`).
524 For a more complete list of ways to spell object names, see
525 "SPECIFYING REVISIONS" section in linkgit:gitrevisions[7].
528 File/Directory Structure
529 ------------------------
531 Please see the linkgit:gitrepository-layout[5] document.
533 Read linkgit:githooks[5] for more details about each hook.
535 Higher level SCMs may provide and manage additional information in the
541 Please see linkgit:gitglossary[7].
544 Environment Variables
545 ---------------------
546 Various git commands use the following environment variables:
550 These environment variables apply to 'all' core git commands. Nb: it
551 is worth noting that they may be used/overridden by SCMS sitting above
552 git so take care if using Cogito etc.
555 This environment allows the specification of an alternate
556 index file. If not specified, the default of `$GIT_DIR/index`
559 'GIT_OBJECT_DIRECTORY'::
560 If the object storage directory is specified via this
561 environment variable then the sha1 directories are created
562 underneath - otherwise the default `$GIT_DIR/objects`
565 'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
566 Due to the immutable nature of git objects, old objects can be
567 archived into shared, read-only directories. This variable
568 specifies a ":" separated (on Windows ";" separated) list
569 of git object directories which can be used to search for git
570 objects. New objects will not be written to these directories.
573 If the 'GIT_DIR' environment variable is set then it
574 specifies a path to use instead of the default `.git`
575 for the base of the repository.
578 Set the path to the working tree. The value will not be
579 used in combination with repositories found automatically in
580 a .git directory (i.e. $GIT_DIR is not set).
581 This can also be controlled by the '--work-tree' command line
582 option and the core.worktree configuration variable.
584 'GIT_CEILING_DIRECTORIES'::
585 This should be a colon-separated list of absolute paths.
586 If set, it is a list of directories that git should not chdir
587 up into while looking for a repository directory.
588 It will not exclude the current working directory or
589 a GIT_DIR set on the command line or in the environment.
590 (Useful for excluding slow-loading network directories.)
592 'GIT_DISCOVERY_ACROSS_FILESYSTEM'::
593 When run in a directory that does not have ".git" repository
594 directory, git tries to find such a directory in the parent
595 directories to find the top of the working tree, but by default it
596 does not cross filesystem boundaries. This environment variable
597 can be set to true to tell git not to stop at filesystem
598 boundaries. Like 'GIT_CEILING_DIRECTORIES', this will not affect
599 an explicit repository directory set via 'GIT_DIR' or on the
607 'GIT_COMMITTER_NAME'::
608 'GIT_COMMITTER_EMAIL'::
609 'GIT_COMMITTER_DATE'::
611 see linkgit:git-commit-tree[1]
616 Only valid setting is "--unified=??" or "-u??" to set the
617 number of context lines shown when a unified diff is created.
618 This takes precedence over any "-U" or "--unified" option
619 value passed on the git diff command line.
621 'GIT_EXTERNAL_DIFF'::
622 When the environment variable 'GIT_EXTERNAL_DIFF' is set, the
623 program named by it is called, instead of the diff invocation
624 described above. For a path that is added, removed, or modified,
625 'GIT_EXTERNAL_DIFF' is called with 7 parameters:
627 path old-file old-hex old-mode new-file new-hex new-mode
631 <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the
632 contents of <old|new>,
633 <old|new>-hex:: are the 40-hexdigit SHA1 hashes,
634 <old|new>-mode:: are the octal representation of the file modes.
636 The file parameters can point at the user's working file
637 (e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
638 when a new file is added), or a temporary file (e.g. `old-file` in the
639 index). 'GIT_EXTERNAL_DIFF' should not worry about unlinking the
640 temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits.
642 For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1
647 'GIT_MERGE_VERBOSITY'::
648 A number controlling the amount of output shown by
649 the recursive merge strategy. Overrides merge.verbosity.
650 See linkgit:git-merge[1]
653 This environment variable overrides `$PAGER`. If it is set
654 to an empty string or to the value "cat", git will not launch
655 a pager. See also the `core.pager` option in
656 linkgit:git-config[1].
659 If this environment variable is set then 'git fetch'
660 and 'git push' will use this command instead
661 of 'ssh' when they need to connect to a remote system.
662 The '$GIT_SSH' command will be given exactly two arguments:
663 the 'username@host' (or just 'host') from the URL and the
664 shell command to execute on that remote system.
666 To pass options to the program that you want to list in GIT_SSH
667 you will need to wrap the program and options into a shell script,
668 then set GIT_SSH to refer to the shell script.
670 Usually it is easier to configure any desired options through your
671 personal `.ssh/config` file. Please consult your ssh documentation
675 If this environment variable is set, then git commands which need to
676 acquire passwords or passphrases (e.g. for HTTP or IMAP authentication)
677 will call this program with a suitable prompt as command line argument
678 and read the password from its STDOUT. See also the 'core.askpass'
679 option in linkgit:git-config[1].
682 If this environment variable is set to "1", then commands such
683 as 'git blame' (in incremental mode), 'git rev-list', 'git log',
684 and 'git whatchanged' will force a flush of the output stream
685 after each commit-oriented record have been flushed. If this
686 variable is set to "0", the output of these commands will be done
687 using completely buffered I/O. If this environment variable is
688 not set, git will choose buffered or record-oriented flushing
689 based on whether stdout appears to be redirected to a file or not.
692 If this variable is set to "1", "2" or "true" (comparison
693 is case insensitive), git will print `trace:` messages on
694 stderr telling about alias expansion, built-in command
695 execution and external command execution.
696 If this variable is set to an integer value greater than 1
697 and lower than 10 (strictly) then git will interpret this
698 value as an open file descriptor and will try to write the
699 trace messages into this file descriptor.
700 Alternatively, if this variable is set to an absolute path
701 (starting with a '/' character), git will interpret this
702 as a file path and will try to write the trace messages
705 Discussion[[Discussion]]
706 ------------------------
708 More detail on the following is available from the
709 link:user-manual.html#git-concepts[git concepts chapter of the
710 user-manual] and linkgit:gitcore-tutorial[7].
712 A git project normally consists of a working directory with a ".git"
713 subdirectory at the top level. The .git directory contains, among other
714 things, a compressed object database representing the complete history
715 of the project, an "index" file which links that history to the current
716 contents of the working tree, and named pointers into that history such
717 as tags and branch heads.
719 The object database contains objects of three main types: blobs, which
720 hold file data; trees, which point to blobs and other trees to build up
721 directory hierarchies; and commits, which each reference a single tree
722 and some number of parent commits.
724 The commit, equivalent to what other systems call a "changeset" or
725 "version", represents a step in the project's history, and each parent
726 represents an immediately preceding step. Commits with more than one
727 parent represent merges of independent lines of development.
729 All objects are named by the SHA1 hash of their contents, normally
730 written as a string of 40 hex digits. Such names are globally unique.
731 The entire history leading up to a commit can be vouched for by signing
732 just that commit. A fourth object type, the tag, is provided for this
735 When first created, objects are stored in individual files, but for
736 efficiency may later be compressed together into "pack files".
738 Named pointers called refs mark interesting points in history. A ref
739 may contain the SHA1 name of an object or the name of another ref. Refs
740 with names beginning `ref/head/` contain the SHA1 name of the most
741 recent commit (or "head") of a branch under development. SHA1 names of
742 tags of interest are stored under `ref/tags/`. A special ref named
743 `HEAD` contains the name of the currently checked-out branch.
745 The index file is initialized with a list of all paths and, for each
746 path, a blob object and a set of attributes. The blob object represents
747 the contents of the file as of the head of the current branch. The
748 attributes (last modified time, size, etc.) are taken from the
749 corresponding file in the working tree. Subsequent changes to the
750 working tree can be found by comparing these attributes. The index may
751 be updated with new content, and new commits may be created from the
752 content stored in the index.
754 The index is also capable of storing multiple entries (called "stages")
755 for a given pathname. These stages are used to hold the various
756 unmerged version of a file when a merge is in progress.
760 Git was started by Linus Torvalds, and is currently maintained by Junio
761 C Hamano. Numerous contributions have come from the git mailing list
762 <git@vger.kernel.org>. For a more complete list of contributors, see
763 http://git-scm.com/about. If you have a clone of git.git itself, the
764 output of linkgit:git-shortlog[1] and linkgit:git-blame[1] can show you
765 the authors for specific parts of the project.
770 Report bugs to the Git mailing list <git@vger.kernel.org> where the
771 development and maintenance is primarily done. You do not have to be
772 subscribed to the list to send a message there.
776 linkgit:gittutorial[7], linkgit:gittutorial-2[7],
777 link:everyday.html[Everyday Git], linkgit:gitcvs-migration[7],
778 linkgit:gitglossary[7], linkgit:gitcore-tutorial[7],
779 linkgit:gitcli[7], link:user-manual.html[The Git User's Manual],
780 linkgit:gitworkflows[7]
784 Part of the linkgit:git[1] suite