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:v1.7.5.4/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, without trailing slash, where git's HTML
295 documentation is installed and exit.
298 Print the manpath (see `man(1)`) for the man pages for
299 this version of git and exit.
302 Print the path where the Info files documenting this
303 version of git are installed and exit.
307 Pipe all output into 'less' (or if set, $PAGER) if standard
308 output is a terminal. This overrides the `pager.<cmd>`
309 configuration options (see the "Configuration Mechanism" section
313 Do not pipe git output into a pager.
316 Set the path to the repository. This can also be controlled by
317 setting the GIT_DIR environment variable. It can be an absolute
318 path or relative path to current working directory.
321 Set the path to the working tree. It can be an absolute path
322 or a path relative to the current working directory.
323 This can also be controlled by setting the GIT_WORK_TREE
324 environment variable and the core.worktree configuration
325 variable (see core.worktree in linkgit:git-config[1] for a
326 more detailed discussion).
329 Treat the repository as a bare repository. If GIT_DIR
330 environment is not set, it is set to the current working
333 --no-replace-objects::
334 Do not use replacement refs to replace git objects. See
335 linkgit:git-replace[1] for more information.
338 FURTHER DOCUMENTATION
339 ---------------------
341 See the references above to get started using git. The following is
342 probably more detail than necessary for a first-time user.
344 The link:user-manual.html#git-concepts[git concepts chapter of the
345 user-manual] and linkgit:gitcore-tutorial[7] both provide
346 introductions to the underlying git architecture.
348 See linkgit:gitworkflows[7] for an overview of recommended workflows.
350 See also the link:howto-index.html[howto] documents for some useful
353 The internals are documented in the
354 link:technical/api-index.html[GIT API documentation].
359 We divide git into high level ("porcelain") commands and low level
360 ("plumbing") commands.
362 High-level commands (porcelain)
363 -------------------------------
365 We separate the porcelain commands into the main commands and some
366 ancillary user utilities.
368 Main porcelain commands
369 ~~~~~~~~~~~~~~~~~~~~~~~
371 include::cmds-mainporcelain.txt[]
377 include::cmds-ancillarymanipulators.txt[]
381 include::cmds-ancillaryinterrogators.txt[]
384 Interacting with Others
385 ~~~~~~~~~~~~~~~~~~~~~~~
387 These commands are to interact with foreign SCM and with other
388 people via patch over e-mail.
390 include::cmds-foreignscminterface.txt[]
393 Low-level commands (plumbing)
394 -----------------------------
396 Although git includes its
397 own porcelain layer, its low-level commands are sufficient to support
398 development of alternative porcelains. Developers of such porcelains
399 might start by reading about linkgit:git-update-index[1] and
400 linkgit:git-read-tree[1].
402 The interface (input, output, set of options and the semantics)
403 to these low-level commands are meant to be a lot more stable
404 than Porcelain level commands, because these commands are
405 primarily for scripted use. The interface to Porcelain commands
406 on the other hand are subject to change in order to improve the
409 The following description divides
410 the low-level commands into commands that manipulate objects (in
411 the repository, index, and working tree), commands that interrogate and
412 compare objects, and commands that move objects and references between
416 Manipulation commands
417 ~~~~~~~~~~~~~~~~~~~~~
419 include::cmds-plumbingmanipulators.txt[]
422 Interrogation commands
423 ~~~~~~~~~~~~~~~~~~~~~~
425 include::cmds-plumbinginterrogators.txt[]
427 In general, the interrogate commands do not touch the files in
431 Synching repositories
432 ~~~~~~~~~~~~~~~~~~~~~
434 include::cmds-synchingrepositories.txt[]
436 The following are helper commands used by the above; end users
437 typically do not use them directly.
439 include::cmds-synchelpers.txt[]
442 Internal helper commands
443 ~~~~~~~~~~~~~~~~~~~~~~~~
445 These are internal helper commands used by other commands; end
446 users typically do not use them directly.
448 include::cmds-purehelpers.txt[]
451 Configuration Mechanism
452 -----------------------
454 Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file
455 is used to hold per-repository configuration options. It is a
456 simple text file modeled after `.ini` format familiar to some
457 people. Here is an example:
461 # A '#' or ';' character indicates a comment.
466 ; Don't trust file modes
471 name = "Junio C Hamano"
472 email = "junkio@twinsun.com"
476 Various commands read from the configuration file and adjust
477 their operation accordingly. See linkgit:git-config[1] for a
481 Identifier Terminology
482 ----------------------
484 Indicates the object name for any type of object.
487 Indicates a blob object name.
490 Indicates a tree object name.
493 Indicates a commit object name.
496 Indicates a tree, commit or tag object name. A
497 command that takes a <tree-ish> argument ultimately wants to
498 operate on a <tree> object but automatically dereferences
499 <commit> and <tag> objects that point at a <tree>.
502 Indicates a commit or tag object name. A
503 command that takes a <commit-ish> argument ultimately wants to
504 operate on a <commit> object but automatically dereferences
505 <tag> objects that point at a <commit>.
508 Indicates that an object type is required.
509 Currently one of: `blob`, `tree`, `commit`, or `tag`.
512 Indicates a filename - almost always relative to the
513 root of the tree structure `GIT_INDEX_FILE` describes.
517 Any git command accepting any <object> can also use the following
521 indicates the head of the current branch (i.e. the
522 contents of `$GIT_DIR/HEAD`).
526 (i.e. the contents of `$GIT_DIR/refs/tags/<tag>`).
530 (i.e. the contents of `$GIT_DIR/refs/heads/<head>`).
532 For a more complete list of ways to spell object names, see
533 "SPECIFYING REVISIONS" section in linkgit:gitrevisions[7].
536 File/Directory Structure
537 ------------------------
539 Please see the linkgit:gitrepository-layout[5] document.
541 Read linkgit:githooks[5] for more details about each hook.
543 Higher level SCMs may provide and manage additional information in the
549 Please see linkgit:gitglossary[7].
552 Environment Variables
553 ---------------------
554 Various git commands use the following environment variables:
558 These environment variables apply to 'all' core git commands. Nb: it
559 is worth noting that they may be used/overridden by SCMS sitting above
560 git so take care if using Cogito etc.
563 This environment allows the specification of an alternate
564 index file. If not specified, the default of `$GIT_DIR/index`
567 'GIT_OBJECT_DIRECTORY'::
568 If the object storage directory is specified via this
569 environment variable then the sha1 directories are created
570 underneath - otherwise the default `$GIT_DIR/objects`
573 'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
574 Due to the immutable nature of git objects, old objects can be
575 archived into shared, read-only directories. This variable
576 specifies a ":" separated (on Windows ";" separated) list
577 of git object directories which can be used to search for git
578 objects. New objects will not be written to these directories.
581 If the 'GIT_DIR' environment variable is set then it
582 specifies a path to use instead of the default `.git`
583 for the base of the repository.
586 Set the path to the working tree. The value will not be
587 used in combination with repositories found automatically in
588 a .git directory (i.e. $GIT_DIR is not set).
589 This can also be controlled by the '--work-tree' command line
590 option and the core.worktree configuration variable.
592 'GIT_CEILING_DIRECTORIES'::
593 This should be a colon-separated list of absolute paths.
594 If set, it is a list of directories that git should not chdir
595 up into while looking for a repository directory.
596 It will not exclude the current working directory or
597 a GIT_DIR set on the command line or in the environment.
598 (Useful for excluding slow-loading network directories.)
600 'GIT_DISCOVERY_ACROSS_FILESYSTEM'::
601 When run in a directory that does not have ".git" repository
602 directory, git tries to find such a directory in the parent
603 directories to find the top of the working tree, but by default it
604 does not cross filesystem boundaries. This environment variable
605 can be set to true to tell git not to stop at filesystem
606 boundaries. Like 'GIT_CEILING_DIRECTORIES', this will not affect
607 an explicit repository directory set via 'GIT_DIR' or on the
615 'GIT_COMMITTER_NAME'::
616 'GIT_COMMITTER_EMAIL'::
617 'GIT_COMMITTER_DATE'::
619 see linkgit:git-commit-tree[1]
624 Only valid setting is "--unified=??" or "-u??" to set the
625 number of context lines shown when a unified diff is created.
626 This takes precedence over any "-U" or "--unified" option
627 value passed on the git diff command line.
629 'GIT_EXTERNAL_DIFF'::
630 When the environment variable 'GIT_EXTERNAL_DIFF' is set, the
631 program named by it is called, instead of the diff invocation
632 described above. For a path that is added, removed, or modified,
633 'GIT_EXTERNAL_DIFF' is called with 7 parameters:
635 path old-file old-hex old-mode new-file new-hex new-mode
639 <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the
640 contents of <old|new>,
641 <old|new>-hex:: are the 40-hexdigit SHA1 hashes,
642 <old|new>-mode:: are the octal representation of the file modes.
644 The file parameters can point at the user's working file
645 (e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
646 when a new file is added), or a temporary file (e.g. `old-file` in the
647 index). 'GIT_EXTERNAL_DIFF' should not worry about unlinking the
648 temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits.
650 For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1
655 'GIT_MERGE_VERBOSITY'::
656 A number controlling the amount of output shown by
657 the recursive merge strategy. Overrides merge.verbosity.
658 See linkgit:git-merge[1]
661 This environment variable overrides `$PAGER`. If it is set
662 to an empty string or to the value "cat", git will not launch
663 a pager. See also the `core.pager` option in
664 linkgit:git-config[1].
667 If this environment variable is set then 'git fetch'
668 and 'git push' will use this command instead
669 of 'ssh' when they need to connect to a remote system.
670 The '$GIT_SSH' command will be given exactly two arguments:
671 the 'username@host' (or just 'host') from the URL and the
672 shell command to execute on that remote system.
674 To pass options to the program that you want to list in GIT_SSH
675 you will need to wrap the program and options into a shell script,
676 then set GIT_SSH to refer to the shell script.
678 Usually it is easier to configure any desired options through your
679 personal `.ssh/config` file. Please consult your ssh documentation
683 If this environment variable is set, then git commands which need to
684 acquire passwords or passphrases (e.g. for HTTP or IMAP authentication)
685 will call this program with a suitable prompt as command line argument
686 and read the password from its STDOUT. See also the 'core.askpass'
687 option in linkgit:git-config[1].
690 If this environment variable is set to "1", then commands such
691 as 'git blame' (in incremental mode), 'git rev-list', 'git log',
692 and 'git whatchanged' will force a flush of the output stream
693 after each commit-oriented record have been flushed. If this
694 variable is set to "0", the output of these commands will be done
695 using completely buffered I/O. If this environment variable is
696 not set, git will choose buffered or record-oriented flushing
697 based on whether stdout appears to be redirected to a file or not.
700 If this variable is set to "1", "2" or "true" (comparison
701 is case insensitive), git will print `trace:` messages on
702 stderr telling about alias expansion, built-in command
703 execution and external command execution.
704 If this variable is set to an integer value greater than 1
705 and lower than 10 (strictly) then git will interpret this
706 value as an open file descriptor and will try to write the
707 trace messages into this file descriptor.
708 Alternatively, if this variable is set to an absolute path
709 (starting with a '/' character), git will interpret this
710 as a file path and will try to write the trace messages
713 Discussion[[Discussion]]
714 ------------------------
716 More detail on the following is available from the
717 link:user-manual.html#git-concepts[git concepts chapter of the
718 user-manual] and linkgit:gitcore-tutorial[7].
720 A git project normally consists of a working directory with a ".git"
721 subdirectory at the top level. The .git directory contains, among other
722 things, a compressed object database representing the complete history
723 of the project, an "index" file which links that history to the current
724 contents of the working tree, and named pointers into that history such
725 as tags and branch heads.
727 The object database contains objects of three main types: blobs, which
728 hold file data; trees, which point to blobs and other trees to build up
729 directory hierarchies; and commits, which each reference a single tree
730 and some number of parent commits.
732 The commit, equivalent to what other systems call a "changeset" or
733 "version", represents a step in the project's history, and each parent
734 represents an immediately preceding step. Commits with more than one
735 parent represent merges of independent lines of development.
737 All objects are named by the SHA1 hash of their contents, normally
738 written as a string of 40 hex digits. Such names are globally unique.
739 The entire history leading up to a commit can be vouched for by signing
740 just that commit. A fourth object type, the tag, is provided for this
743 When first created, objects are stored in individual files, but for
744 efficiency may later be compressed together into "pack files".
746 Named pointers called refs mark interesting points in history. A ref
747 may contain the SHA1 name of an object or the name of another ref. Refs
748 with names beginning `ref/head/` contain the SHA1 name of the most
749 recent commit (or "head") of a branch under development. SHA1 names of
750 tags of interest are stored under `ref/tags/`. A special ref named
751 `HEAD` contains the name of the currently checked-out branch.
753 The index file is initialized with a list of all paths and, for each
754 path, a blob object and a set of attributes. The blob object represents
755 the contents of the file as of the head of the current branch. The
756 attributes (last modified time, size, etc.) are taken from the
757 corresponding file in the working tree. Subsequent changes to the
758 working tree can be found by comparing these attributes. The index may
759 be updated with new content, and new commits may be created from the
760 content stored in the index.
762 The index is also capable of storing multiple entries (called "stages")
763 for a given pathname. These stages are used to hold the various
764 unmerged version of a file when a merge is in progress.
768 Git was started by Linus Torvalds, and is currently maintained by Junio
769 C Hamano. Numerous contributions have come from the git mailing list
770 <git@vger.kernel.org>. For a more complete list of contributors, see
771 http://git-scm.com/about. If you have a clone of git.git itself, the
772 output of linkgit:git-shortlog[1] and linkgit:git-blame[1] can show you
773 the authors for specific parts of the project.
778 Report bugs to the Git mailing list <git@vger.kernel.org> where the
779 development and maintenance is primarily done. You do not have to be
780 subscribed to the list to send a message there.
784 linkgit:gittutorial[7], linkgit:gittutorial-2[7],
785 link:everyday.html[Everyday Git], linkgit:gitcvs-migration[7],
786 linkgit:gitglossary[7], linkgit:gitcore-tutorial[7],
787 linkgit:gitcli[7], link:user-manual.html[The Git User's Manual],
788 linkgit:gitworkflows[7]
792 Part of the linkgit:git[1] suite