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:v1.7.8/git.html[documentation for release 1.7.8]
50 link:RelNotes/1.7.8.txt[1.7.8].
52 * link:v1.7.7.1/git.html[documentation for release 1.7.7.1]
55 link:RelNotes/1.7.7.1.txt[1.7.7.1],
56 link:RelNotes/1.7.7.txt[1.7.7].
58 * link:v1.7.6.4/git.html[documentation for release 1.7.6.4]
61 link:RelNotes/1.7.6.4.txt[1.7.6.4],
62 link:RelNotes/1.7.6.3.txt[1.7.6.3],
63 link:RelNotes/1.7.6.2.txt[1.7.6.2],
64 link:RelNotes/1.7.6.1.txt[1.7.6.1],
65 link:RelNotes/1.7.6.txt[1.7.6].
67 * link:v1.7.5.4/git.html[documentation for release 1.7.5.4]
70 link:RelNotes/1.7.5.4.txt[1.7.5.4],
71 link:RelNotes/1.7.5.3.txt[1.7.5.3],
72 link:RelNotes/1.7.5.2.txt[1.7.5.2],
73 link:RelNotes/1.7.5.1.txt[1.7.5.1],
74 link:RelNotes/1.7.5.txt[1.7.5].
76 * link:v1.7.4.5/git.html[documentation for release 1.7.4.5]
79 link:RelNotes/1.7.4.5.txt[1.7.4.5],
80 link:RelNotes/1.7.4.4.txt[1.7.4.4],
81 link:RelNotes/1.7.4.3.txt[1.7.4.3],
82 link:RelNotes/1.7.4.2.txt[1.7.4.2],
83 link:RelNotes/1.7.4.1.txt[1.7.4.1],
84 link:RelNotes/1.7.4.txt[1.7.4].
86 * link:v1.7.3.5/git.html[documentation for release 1.7.3.5]
89 link:RelNotes/1.7.3.5.txt[1.7.3.5],
90 link:RelNotes/1.7.3.4.txt[1.7.3.4],
91 link:RelNotes/1.7.3.3.txt[1.7.3.3],
92 link:RelNotes/1.7.3.2.txt[1.7.3.2],
93 link:RelNotes/1.7.3.1.txt[1.7.3.1],
94 link:RelNotes/1.7.3.txt[1.7.3].
96 * link:v1.7.2.5/git.html[documentation for release 1.7.2.5]
99 link:RelNotes/1.7.2.5.txt[1.7.2.5],
100 link:RelNotes/1.7.2.4.txt[1.7.2.4],
101 link:RelNotes/1.7.2.3.txt[1.7.2.3],
102 link:RelNotes/1.7.2.2.txt[1.7.2.2],
103 link:RelNotes/1.7.2.1.txt[1.7.2.1],
104 link:RelNotes/1.7.2.txt[1.7.2].
106 * link:v1.7.1.4/git.html[documentation for release 1.7.1.4]
109 link:RelNotes/1.7.1.4.txt[1.7.1.4],
110 link:RelNotes/1.7.1.3.txt[1.7.1.3],
111 link:RelNotes/1.7.1.2.txt[1.7.1.2],
112 link:RelNotes/1.7.1.1.txt[1.7.1.1],
113 link:RelNotes/1.7.1.txt[1.7.1].
115 * link:v1.7.0.9/git.html[documentation for release 1.7.0.9]
118 link:RelNotes/1.7.0.9.txt[1.7.0.9],
119 link:RelNotes/1.7.0.8.txt[1.7.0.8],
120 link:RelNotes/1.7.0.7.txt[1.7.0.7],
121 link:RelNotes/1.7.0.6.txt[1.7.0.6],
122 link:RelNotes/1.7.0.5.txt[1.7.0.5],
123 link:RelNotes/1.7.0.4.txt[1.7.0.4],
124 link:RelNotes/1.7.0.3.txt[1.7.0.3],
125 link:RelNotes/1.7.0.2.txt[1.7.0.2],
126 link:RelNotes/1.7.0.1.txt[1.7.0.1],
127 link:RelNotes/1.7.0.txt[1.7.0].
129 * link:v1.6.6.3/git.html[documentation for release 1.6.6.3]
132 link:RelNotes/1.6.6.3.txt[1.6.6.3],
133 link:RelNotes/1.6.6.2.txt[1.6.6.2],
134 link:RelNotes/1.6.6.1.txt[1.6.6.1],
135 link:RelNotes/1.6.6.txt[1.6.6].
137 * link:v1.6.5.9/git.html[documentation for release 1.6.5.9]
140 link:RelNotes/1.6.5.9.txt[1.6.5.9],
141 link:RelNotes/1.6.5.8.txt[1.6.5.8],
142 link:RelNotes/1.6.5.7.txt[1.6.5.7],
143 link:RelNotes/1.6.5.6.txt[1.6.5.6],
144 link:RelNotes/1.6.5.5.txt[1.6.5.5],
145 link:RelNotes/1.6.5.4.txt[1.6.5.4],
146 link:RelNotes/1.6.5.3.txt[1.6.5.3],
147 link:RelNotes/1.6.5.2.txt[1.6.5.2],
148 link:RelNotes/1.6.5.1.txt[1.6.5.1],
149 link:RelNotes/1.6.5.txt[1.6.5].
151 * link:v1.6.4.5/git.html[documentation for release 1.6.4.5]
154 link:RelNotes/1.6.4.5.txt[1.6.4.5],
155 link:RelNotes/1.6.4.4.txt[1.6.4.4],
156 link:RelNotes/1.6.4.3.txt[1.6.4.3],
157 link:RelNotes/1.6.4.2.txt[1.6.4.2],
158 link:RelNotes/1.6.4.1.txt[1.6.4.1],
159 link:RelNotes/1.6.4.txt[1.6.4].
161 * link:v1.6.3.4/git.html[documentation for release 1.6.3.4]
164 link:RelNotes/1.6.3.4.txt[1.6.3.4],
165 link:RelNotes/1.6.3.3.txt[1.6.3.3],
166 link:RelNotes/1.6.3.2.txt[1.6.3.2],
167 link:RelNotes/1.6.3.1.txt[1.6.3.1],
168 link:RelNotes/1.6.3.txt[1.6.3].
171 link:RelNotes/1.6.2.5.txt[1.6.2.5],
172 link:RelNotes/1.6.2.4.txt[1.6.2.4],
173 link:RelNotes/1.6.2.3.txt[1.6.2.3],
174 link:RelNotes/1.6.2.2.txt[1.6.2.2],
175 link:RelNotes/1.6.2.1.txt[1.6.2.1],
176 link:RelNotes/1.6.2.txt[1.6.2].
178 * link:v1.6.1.3/git.html[documentation for release 1.6.1.3]
181 link:RelNotes/1.6.1.3.txt[1.6.1.3],
182 link:RelNotes/1.6.1.2.txt[1.6.1.2],
183 link:RelNotes/1.6.1.1.txt[1.6.1.1],
184 link:RelNotes/1.6.1.txt[1.6.1].
186 * link:v1.6.0.6/git.html[documentation for release 1.6.0.6]
189 link:RelNotes/1.6.0.6.txt[1.6.0.6],
190 link:RelNotes/1.6.0.5.txt[1.6.0.5],
191 link:RelNotes/1.6.0.4.txt[1.6.0.4],
192 link:RelNotes/1.6.0.3.txt[1.6.0.3],
193 link:RelNotes/1.6.0.2.txt[1.6.0.2],
194 link:RelNotes/1.6.0.1.txt[1.6.0.1],
195 link:RelNotes/1.6.0.txt[1.6.0].
197 * link:v1.5.6.6/git.html[documentation for release 1.5.6.6]
200 link:RelNotes/1.5.6.6.txt[1.5.6.6],
201 link:RelNotes/1.5.6.5.txt[1.5.6.5],
202 link:RelNotes/1.5.6.4.txt[1.5.6.4],
203 link:RelNotes/1.5.6.3.txt[1.5.6.3],
204 link:RelNotes/1.5.6.2.txt[1.5.6.2],
205 link:RelNotes/1.5.6.1.txt[1.5.6.1],
206 link:RelNotes/1.5.6.txt[1.5.6].
208 * link:v1.5.5.6/git.html[documentation for release 1.5.5.6]
211 link:RelNotes/1.5.5.6.txt[1.5.5.6],
212 link:RelNotes/1.5.5.5.txt[1.5.5.5],
213 link:RelNotes/1.5.5.4.txt[1.5.5.4],
214 link:RelNotes/1.5.5.3.txt[1.5.5.3],
215 link:RelNotes/1.5.5.2.txt[1.5.5.2],
216 link:RelNotes/1.5.5.1.txt[1.5.5.1],
217 link:RelNotes/1.5.5.txt[1.5.5].
219 * link:v1.5.4.7/git.html[documentation for release 1.5.4.7]
222 link:RelNotes/1.5.4.7.txt[1.5.4.7],
223 link:RelNotes/1.5.4.6.txt[1.5.4.6],
224 link:RelNotes/1.5.4.5.txt[1.5.4.5],
225 link:RelNotes/1.5.4.4.txt[1.5.4.4],
226 link:RelNotes/1.5.4.3.txt[1.5.4.3],
227 link:RelNotes/1.5.4.2.txt[1.5.4.2],
228 link:RelNotes/1.5.4.1.txt[1.5.4.1],
229 link:RelNotes/1.5.4.txt[1.5.4].
231 * link:v1.5.3.8/git.html[documentation for release 1.5.3.8]
234 link:RelNotes/1.5.3.8.txt[1.5.3.8],
235 link:RelNotes/1.5.3.7.txt[1.5.3.7],
236 link:RelNotes/1.5.3.6.txt[1.5.3.6],
237 link:RelNotes/1.5.3.5.txt[1.5.3.5],
238 link:RelNotes/1.5.3.4.txt[1.5.3.4],
239 link:RelNotes/1.5.3.3.txt[1.5.3.3],
240 link:RelNotes/1.5.3.2.txt[1.5.3.2],
241 link:RelNotes/1.5.3.1.txt[1.5.3.1],
242 link:RelNotes/1.5.3.txt[1.5.3].
244 * link:v1.5.2.5/git.html[documentation for release 1.5.2.5]
247 link:RelNotes/1.5.2.5.txt[1.5.2.5],
248 link:RelNotes/1.5.2.4.txt[1.5.2.4],
249 link:RelNotes/1.5.2.3.txt[1.5.2.3],
250 link:RelNotes/1.5.2.2.txt[1.5.2.2],
251 link:RelNotes/1.5.2.1.txt[1.5.2.1],
252 link:RelNotes/1.5.2.txt[1.5.2].
254 * link:v1.5.1.6/git.html[documentation for release 1.5.1.6]
257 link:RelNotes/1.5.1.6.txt[1.5.1.6],
258 link:RelNotes/1.5.1.5.txt[1.5.1.5],
259 link:RelNotes/1.5.1.4.txt[1.5.1.4],
260 link:RelNotes/1.5.1.3.txt[1.5.1.3],
261 link:RelNotes/1.5.1.2.txt[1.5.1.2],
262 link:RelNotes/1.5.1.1.txt[1.5.1.1],
263 link:RelNotes/1.5.1.txt[1.5.1].
265 * link:v1.5.0.7/git.html[documentation for release 1.5.0.7]
268 link:RelNotes/1.5.0.7.txt[1.5.0.7],
269 link:RelNotes/1.5.0.6.txt[1.5.0.6],
270 link:RelNotes/1.5.0.5.txt[1.5.0.5],
271 link:RelNotes/1.5.0.3.txt[1.5.0.3],
272 link:RelNotes/1.5.0.2.txt[1.5.0.2],
273 link:RelNotes/1.5.0.1.txt[1.5.0.1],
274 link:RelNotes/1.5.0.txt[1.5.0].
276 * documentation for release link:v1.4.4.4/git.html[1.4.4.4],
277 link:v1.3.3/git.html[1.3.3],
278 link:v1.2.6/git.html[1.2.6],
279 link:v1.0.13/git.html[1.0.13].
288 Prints the git suite version that the 'git' program came from.
291 Prints the synopsis and a list of the most commonly used
292 commands. If the option '--all' or '-a' is given then all
293 available commands are printed. If a git command is named this
294 option will bring up the manual page for that command.
296 Other options are available to control how the manual page is
297 displayed. See linkgit:git-help[1] for more information,
298 because `git --help ...` is converted internally into `git
302 Pass a configuration parameter to the command. The value
303 given will override values from configuration files.
304 The <name> is expected in the same format as listed by
305 'git config' (subkeys separated by dots).
307 --exec-path[=<path>]::
308 Path to wherever your core git programs are installed.
309 This can also be controlled by setting the GIT_EXEC_PATH
310 environment variable. If no path is given, 'git' will print
311 the current setting and then exit.
314 Print the path, without trailing slash, where git's HTML
315 documentation is installed and exit.
318 Print the manpath (see `man(1)`) for the man pages for
319 this version of git and exit.
322 Print the path where the Info files documenting this
323 version of git are installed and exit.
327 Pipe all output into 'less' (or if set, $PAGER) if standard
328 output is a terminal. This overrides the `pager.<cmd>`
329 configuration options (see the "Configuration Mechanism" section
333 Do not pipe git output into a pager.
336 Set the path to the repository. This can also be controlled by
337 setting the GIT_DIR environment variable. It can be an absolute
338 path or relative path to current working directory.
341 Set the path to the working tree. It can be an absolute path
342 or a path relative to the current working directory.
343 This can also be controlled by setting the GIT_WORK_TREE
344 environment variable and the core.worktree configuration
345 variable (see core.worktree in linkgit:git-config[1] for a
346 more detailed discussion).
349 Set the git namespace. See linkgit:gitnamespaces[7] for more
350 details. Equivalent to setting the `GIT_NAMESPACE` environment
354 Treat the repository as a bare repository. If GIT_DIR
355 environment is not set, it is set to the current working
358 --no-replace-objects::
359 Do not use replacement refs to replace git objects. See
360 linkgit:git-replace[1] for more information.
363 FURTHER DOCUMENTATION
364 ---------------------
366 See the references above to get started using git. The following is
367 probably more detail than necessary for a first-time user.
369 The link:user-manual.html#git-concepts[git concepts chapter of the
370 user-manual] and linkgit:gitcore-tutorial[7] both provide
371 introductions to the underlying git architecture.
373 See linkgit:gitworkflows[7] for an overview of recommended workflows.
375 See also the link:howto-index.html[howto] documents for some useful
378 The internals are documented in the
379 link:technical/api-index.html[GIT API documentation].
384 We divide git into high level ("porcelain") commands and low level
385 ("plumbing") commands.
387 High-level commands (porcelain)
388 -------------------------------
390 We separate the porcelain commands into the main commands and some
391 ancillary user utilities.
393 Main porcelain commands
394 ~~~~~~~~~~~~~~~~~~~~~~~
396 include::cmds-mainporcelain.txt[]
402 include::cmds-ancillarymanipulators.txt[]
406 include::cmds-ancillaryinterrogators.txt[]
409 Interacting with Others
410 ~~~~~~~~~~~~~~~~~~~~~~~
412 These commands are to interact with foreign SCM and with other
413 people via patch over e-mail.
415 include::cmds-foreignscminterface.txt[]
418 Low-level commands (plumbing)
419 -----------------------------
421 Although git includes its
422 own porcelain layer, its low-level commands are sufficient to support
423 development of alternative porcelains. Developers of such porcelains
424 might start by reading about linkgit:git-update-index[1] and
425 linkgit:git-read-tree[1].
427 The interface (input, output, set of options and the semantics)
428 to these low-level commands are meant to be a lot more stable
429 than Porcelain level commands, because these commands are
430 primarily for scripted use. The interface to Porcelain commands
431 on the other hand are subject to change in order to improve the
434 The following description divides
435 the low-level commands into commands that manipulate objects (in
436 the repository, index, and working tree), commands that interrogate and
437 compare objects, and commands that move objects and references between
441 Manipulation commands
442 ~~~~~~~~~~~~~~~~~~~~~
444 include::cmds-plumbingmanipulators.txt[]
447 Interrogation commands
448 ~~~~~~~~~~~~~~~~~~~~~~
450 include::cmds-plumbinginterrogators.txt[]
452 In general, the interrogate commands do not touch the files in
456 Synching repositories
457 ~~~~~~~~~~~~~~~~~~~~~
459 include::cmds-synchingrepositories.txt[]
461 The following are helper commands used by the above; end users
462 typically do not use them directly.
464 include::cmds-synchelpers.txt[]
467 Internal helper commands
468 ~~~~~~~~~~~~~~~~~~~~~~~~
470 These are internal helper commands used by other commands; end
471 users typically do not use them directly.
473 include::cmds-purehelpers.txt[]
476 Configuration Mechanism
477 -----------------------
479 Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file
480 is used to hold per-repository configuration options. It is a
481 simple text file modeled after `.ini` format familiar to some
482 people. Here is an example:
486 # A '#' or ';' character indicates a comment.
491 ; Don't trust file modes
496 name = "Junio C Hamano"
497 email = "junkio@twinsun.com"
501 Various commands read from the configuration file and adjust
502 their operation accordingly. See linkgit:git-config[1] for a
506 Identifier Terminology
507 ----------------------
509 Indicates the object name for any type of object.
512 Indicates a blob object name.
515 Indicates a tree object name.
518 Indicates a commit object name.
521 Indicates a tree, commit or tag object name. A
522 command that takes a <tree-ish> argument ultimately wants to
523 operate on a <tree> object but automatically dereferences
524 <commit> and <tag> objects that point at a <tree>.
527 Indicates a commit or tag object name. A
528 command that takes a <commit-ish> argument ultimately wants to
529 operate on a <commit> object but automatically dereferences
530 <tag> objects that point at a <commit>.
533 Indicates that an object type is required.
534 Currently one of: `blob`, `tree`, `commit`, or `tag`.
537 Indicates a filename - almost always relative to the
538 root of the tree structure `GIT_INDEX_FILE` describes.
542 Any git command accepting any <object> can also use the following
546 indicates the head of the current branch.
550 (i.e. a `refs/tags/<tag>` reference).
554 (i.e. a `refs/heads/<head>` reference).
556 For a more complete list of ways to spell object names, see
557 "SPECIFYING REVISIONS" section in linkgit:gitrevisions[7].
560 File/Directory Structure
561 ------------------------
563 Please see the linkgit:gitrepository-layout[5] document.
565 Read linkgit:githooks[5] for more details about each hook.
567 Higher level SCMs may provide and manage additional information in the
573 Please see linkgit:gitglossary[7].
576 Environment Variables
577 ---------------------
578 Various git commands use the following environment variables:
582 These environment variables apply to 'all' core git commands. Nb: it
583 is worth noting that they may be used/overridden by SCMS sitting above
584 git so take care if using Cogito etc.
587 This environment allows the specification of an alternate
588 index file. If not specified, the default of `$GIT_DIR/index`
591 'GIT_OBJECT_DIRECTORY'::
592 If the object storage directory is specified via this
593 environment variable then the sha1 directories are created
594 underneath - otherwise the default `$GIT_DIR/objects`
597 'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
598 Due to the immutable nature of git objects, old objects can be
599 archived into shared, read-only directories. This variable
600 specifies a ":" separated (on Windows ";" separated) list
601 of git object directories which can be used to search for git
602 objects. New objects will not be written to these directories.
605 If the 'GIT_DIR' environment variable is set then it
606 specifies a path to use instead of the default `.git`
607 for the base of the repository.
610 Set the path to the working tree. The value will not be
611 used in combination with repositories found automatically in
612 a .git directory (i.e. $GIT_DIR is not set).
613 This can also be controlled by the '--work-tree' command line
614 option and the core.worktree configuration variable.
617 Set the git namespace; see linkgit:gitnamespaces[7] for details.
618 The '--namespace' command-line option also sets this value.
620 'GIT_CEILING_DIRECTORIES'::
621 This should be a colon-separated list of absolute paths.
622 If set, it is a list of directories that git should not chdir
623 up into while looking for a repository directory.
624 It will not exclude the current working directory or
625 a GIT_DIR set on the command line or in the environment.
626 (Useful for excluding slow-loading network directories.)
628 'GIT_DISCOVERY_ACROSS_FILESYSTEM'::
629 When run in a directory that does not have ".git" repository
630 directory, git tries to find such a directory in the parent
631 directories to find the top of the working tree, but by default it
632 does not cross filesystem boundaries. This environment variable
633 can be set to true to tell git not to stop at filesystem
634 boundaries. Like 'GIT_CEILING_DIRECTORIES', this will not affect
635 an explicit repository directory set via 'GIT_DIR' or on the
643 'GIT_COMMITTER_NAME'::
644 'GIT_COMMITTER_EMAIL'::
645 'GIT_COMMITTER_DATE'::
647 see linkgit:git-commit-tree[1]
652 Only valid setting is "--unified=??" or "-u??" to set the
653 number of context lines shown when a unified diff is created.
654 This takes precedence over any "-U" or "--unified" option
655 value passed on the git diff command line.
657 'GIT_EXTERNAL_DIFF'::
658 When the environment variable 'GIT_EXTERNAL_DIFF' is set, the
659 program named by it is called, instead of the diff invocation
660 described above. For a path that is added, removed, or modified,
661 'GIT_EXTERNAL_DIFF' is called with 7 parameters:
663 path old-file old-hex old-mode new-file new-hex new-mode
667 <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the
668 contents of <old|new>,
669 <old|new>-hex:: are the 40-hexdigit SHA1 hashes,
670 <old|new>-mode:: are the octal representation of the file modes.
672 The file parameters can point at the user's working file
673 (e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
674 when a new file is added), or a temporary file (e.g. `old-file` in the
675 index). 'GIT_EXTERNAL_DIFF' should not worry about unlinking the
676 temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits.
678 For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1
683 'GIT_MERGE_VERBOSITY'::
684 A number controlling the amount of output shown by
685 the recursive merge strategy. Overrides merge.verbosity.
686 See linkgit:git-merge[1]
689 This environment variable overrides `$PAGER`. If it is set
690 to an empty string or to the value "cat", git will not launch
691 a pager. See also the `core.pager` option in
692 linkgit:git-config[1].
695 If this environment variable is set then 'git fetch'
696 and 'git push' will use this command instead
697 of 'ssh' when they need to connect to a remote system.
698 The '$GIT_SSH' command will be given exactly two arguments:
699 the 'username@host' (or just 'host') from the URL and the
700 shell command to execute on that remote system.
702 To pass options to the program that you want to list in GIT_SSH
703 you will need to wrap the program and options into a shell script,
704 then set GIT_SSH to refer to the shell script.
706 Usually it is easier to configure any desired options through your
707 personal `.ssh/config` file. Please consult your ssh documentation
711 If this environment variable is set, then git commands which need to
712 acquire passwords or passphrases (e.g. for HTTP or IMAP authentication)
713 will call this program with a suitable prompt as command line argument
714 and read the password from its STDOUT. See also the 'core.askpass'
715 option in linkgit:git-config[1].
718 If this environment variable is set to "1", then commands such
719 as 'git blame' (in incremental mode), 'git rev-list', 'git log',
720 and 'git whatchanged' will force a flush of the output stream
721 after each commit-oriented record have been flushed. If this
722 variable is set to "0", the output of these commands will be done
723 using completely buffered I/O. If this environment variable is
724 not set, git will choose buffered or record-oriented flushing
725 based on whether stdout appears to be redirected to a file or not.
728 If this variable is set to "1", "2" or "true" (comparison
729 is case insensitive), git will print `trace:` messages on
730 stderr telling about alias expansion, built-in command
731 execution and external command execution.
732 If this variable is set to an integer value greater than 1
733 and lower than 10 (strictly) then git will interpret this
734 value as an open file descriptor and will try to write the
735 trace messages into this file descriptor.
736 Alternatively, if this variable is set to an absolute path
737 (starting with a '/' character), git will interpret this
738 as a file path and will try to write the trace messages
741 Discussion[[Discussion]]
742 ------------------------
744 More detail on the following is available from the
745 link:user-manual.html#git-concepts[git concepts chapter of the
746 user-manual] and linkgit:gitcore-tutorial[7].
748 A git project normally consists of a working directory with a ".git"
749 subdirectory at the top level. The .git directory contains, among other
750 things, a compressed object database representing the complete history
751 of the project, an "index" file which links that history to the current
752 contents of the working tree, and named pointers into that history such
753 as tags and branch heads.
755 The object database contains objects of three main types: blobs, which
756 hold file data; trees, which point to blobs and other trees to build up
757 directory hierarchies; and commits, which each reference a single tree
758 and some number of parent commits.
760 The commit, equivalent to what other systems call a "changeset" or
761 "version", represents a step in the project's history, and each parent
762 represents an immediately preceding step. Commits with more than one
763 parent represent merges of independent lines of development.
765 All objects are named by the SHA1 hash of their contents, normally
766 written as a string of 40 hex digits. Such names are globally unique.
767 The entire history leading up to a commit can be vouched for by signing
768 just that commit. A fourth object type, the tag, is provided for this
771 When first created, objects are stored in individual files, but for
772 efficiency may later be compressed together into "pack files".
774 Named pointers called refs mark interesting points in history. A ref
775 may contain the SHA1 name of an object or the name of another ref. Refs
776 with names beginning `ref/head/` contain the SHA1 name of the most
777 recent commit (or "head") of a branch under development. SHA1 names of
778 tags of interest are stored under `ref/tags/`. A special ref named
779 `HEAD` contains the name of the currently checked-out branch.
781 The index file is initialized with a list of all paths and, for each
782 path, a blob object and a set of attributes. The blob object represents
783 the contents of the file as of the head of the current branch. The
784 attributes (last modified time, size, etc.) are taken from the
785 corresponding file in the working tree. Subsequent changes to the
786 working tree can be found by comparing these attributes. The index may
787 be updated with new content, and new commits may be created from the
788 content stored in the index.
790 The index is also capable of storing multiple entries (called "stages")
791 for a given pathname. These stages are used to hold the various
792 unmerged version of a file when a merge is in progress.
796 Git was started by Linus Torvalds, and is currently maintained by Junio
797 C Hamano. Numerous contributions have come from the git mailing list
798 <git@vger.kernel.org>. For a more complete list of contributors, see
799 http://git-scm.com/about. If you have a clone of git.git itself, the
800 output of linkgit:git-shortlog[1] and linkgit:git-blame[1] can show you
801 the authors for specific parts of the project.
806 Report bugs to the Git mailing list <git@vger.kernel.org> where the
807 development and maintenance is primarily done. You do not have to be
808 subscribed to the list to send a message there.
812 linkgit:gittutorial[7], linkgit:gittutorial-2[7],
813 link:everyday.html[Everyday Git], linkgit:gitcvs-migration[7],
814 linkgit:gitglossary[7], linkgit:gitcore-tutorial[7],
815 linkgit:gitcli[7], link:user-manual.html[The Git User's Manual],
816 linkgit:gitworkflows[7]
820 Part of the linkgit:git[1] suite