Merge branch 'maint' to synchronize with 1.5.3.6
[git/git.git] / Documentation / git.txt
1 git(7)
2 ======
3
4 NAME
5 ----
6 git - the stupid content tracker
7
8
9 SYNOPSIS
10 --------
11 [verse]
12 'git' [--version] [--exec-path[=GIT_EXEC_PATH]]
13 [-p|--paginate|--no-pager]
14 [--bare] [--git-dir=GIT_DIR] [--work-tree=GIT_WORK_TREE]
15 [--help] COMMAND [ARGS]
16
17 DESCRIPTION
18 -----------
19 Git is a fast, scalable, distributed revision control system with an
20 unusually rich command set that provides both high-level operations
21 and full access to internals.
22
23 See this link:tutorial.html[tutorial] to get started, then see
24 link:everyday.html[Everyday Git] for a useful minimum set of commands, and
25 "man git-commandname" for documentation of each command. CVS users may
26 also want to read link:cvs-migration.html[CVS migration]. See
27 link:user-manual.html[Git User's Manual] for a more in-depth
28 introduction.
29
30 The COMMAND is either a name of a Git command (see below) or an alias
31 as defined in the configuration file (see gitlink:git-config[1]).
32
33 Formatted and hyperlinked version of the latest git
34 documentation can be viewed at
35 `http://www.kernel.org/pub/software/scm/git/docs/`.
36
37 ifdef::stalenotes[]
38 [NOTE]
39 ============
40
41 You are reading the documentation for the latest (possibly
42 unreleased) version of git, that is available from 'master'
43 branch of the `git.git` repository.
44 Documentation for older releases are available here:
45
46 * link:v1.5.3/git.html[documentation for release 1.5.3]
47
48 * release notes for
49 link:RelNotes-1.5.3.6.txt[1.5.3.6],
50 link:RelNotes-1.5.3.5.txt[1.5.3.5],
51 link:RelNotes-1.5.3.4.txt[1.5.3.4],
52 link:RelNotes-1.5.3.3.txt[1.5.3.3],
53 link:RelNotes-1.5.3.2.txt[1.5.3.2],
54 link:RelNotes-1.5.3.1.txt[1.5.3.1],
55 link:RelNotes-1.5.3.txt[1.5.3].
56
57 * release notes for
58 link:RelNotes-1.5.2.5.txt[1.5.2.5],
59 link:RelNotes-1.5.2.4.txt[1.5.2.4],
60 link:RelNotes-1.5.2.3.txt[1.5.2.3],
61 link:RelNotes-1.5.2.2.txt[1.5.2.2],
62 link:RelNotes-1.5.2.1.txt[1.5.2.1],
63 link:RelNotes-1.5.2.txt[1.5.2].
64
65 * link:v1.5.1.6/git.html[documentation for release 1.5.1.6]
66
67 * release notes for
68 link:RelNotes-1.5.1.6.txt[1.5.1.6],
69 link:RelNotes-1.5.1.5.txt[1.5.1.5],
70 link:RelNotes-1.5.1.4.txt[1.5.1.4],
71 link:RelNotes-1.5.1.3.txt[1.5.1.3],
72 link:RelNotes-1.5.1.2.txt[1.5.1.2],
73 link:RelNotes-1.5.1.1.txt[1.5.1.1],
74 link:RelNotes-1.5.1.txt[1.5.1].
75
76 * link:v1.5.0.7/git.html[documentation for release 1.5.0.7]
77
78 * release notes for
79 link:RelNotes-1.5.0.7.txt[1.5.0.7],
80 link:RelNotes-1.5.0.6.txt[1.5.0.6],
81 link:RelNotes-1.5.0.5.txt[1.5.0.5],
82 link:RelNotes-1.5.0.3.txt[1.5.0.3],
83 link:RelNotes-1.5.0.2.txt[1.5.0.2],
84 link:RelNotes-1.5.0.1.txt[1.5.0.1],
85 link:RelNotes-1.5.0.txt[1.5.0].
86
87 * documentation for release link:v1.4.4.4/git.html[1.4.4.4],
88 link:v1.3.3/git.html[1.3.3],
89 link:v1.2.6/git.html[1.2.6],
90 link:v1.0.13/git.html[1.0.13].
91
92 ============
93
94 endif::stalenotes[]
95
96 OPTIONS
97 -------
98 --version::
99 Prints the git suite version that the 'git' program came from.
100
101 --help::
102 Prints the synopsis and a list of the most commonly used
103 commands. If a git command is named this option will bring up
104 the man-page for that command. If the option '--all' or '-a' is
105 given then all available commands are printed.
106
107 --exec-path::
108 Path to wherever your core git programs are installed.
109 This can also be controlled by setting the GIT_EXEC_PATH
110 environment variable. If no path is given 'git' will print
111 the current setting and then exit.
112
113 -p|--paginate::
114 Pipe all output into 'less' (or if set, $PAGER).
115
116 --no-pager::
117 Do not pipe git output into a pager.
118
119 --git-dir=<path>::
120 Set the path to the repository. This can also be controlled by
121 setting the GIT_DIR environment variable.
122
123 --work-tree=<path>::
124 Set the path to the working tree. The value will not be
125 used in combination with repositories found automatically in
126 a .git directory (i.e. $GIT_DIR is not set).
127 This can also be controlled by setting the GIT_WORK_TREE
128 environment variable and the core.worktree configuration
129 variable.
130
131 --bare::
132 Treat the repository as a bare repository. If GIT_DIR
133 environment is not set, it is set to the current working
134 directory.
135
136
137 FURTHER DOCUMENTATION
138 ---------------------
139
140 See the references above to get started using git. The following is
141 probably more detail than necessary for a first-time user.
142
143 The link:user-manual.html#git-concepts[git concepts chapter of the
144 user-manual] and the link:core-tutorial.html[Core tutorial] both provide
145 introductions to the underlying git architecture.
146
147 See also the link:howto-index.html[howto] documents for some useful
148 examples.
149
150 GIT COMMANDS
151 ------------
152
153 We divide git into high level ("porcelain") commands and low level
154 ("plumbing") commands.
155
156 High-level commands (porcelain)
157 -------------------------------
158
159 We separate the porcelain commands into the main commands and some
160 ancillary user utilities.
161
162 Main porcelain commands
163 ~~~~~~~~~~~~~~~~~~~~~~~
164
165 include::cmds-mainporcelain.txt[]
166
167 Ancillary Commands
168 ~~~~~~~~~~~~~~~~~~
169 Manipulators:
170
171 include::cmds-ancillarymanipulators.txt[]
172
173 Interrogators:
174
175 include::cmds-ancillaryinterrogators.txt[]
176
177
178 Interacting with Others
179 ~~~~~~~~~~~~~~~~~~~~~~~
180
181 These commands are to interact with foreign SCM and with other
182 people via patch over e-mail.
183
184 include::cmds-foreignscminterface.txt[]
185
186
187 Low-level commands (plumbing)
188 -----------------------------
189
190 Although git includes its
191 own porcelain layer, its low-level commands are sufficient to support
192 development of alternative porcelains. Developers of such porcelains
193 might start by reading about gitlink:git-update-index[1] and
194 gitlink:git-read-tree[1].
195
196 The interface (input, output, set of options and the semantics)
197 to these low-level commands are meant to be a lot more stable
198 than Porcelain level commands, because these commands are
199 primarily for scripted use. The interface to Porcelain commands
200 on the other hand are subject to change in order to improve the
201 end user experience.
202
203 The following description divides
204 the low-level commands into commands that manipulate objects (in
205 the repository, index, and working tree), commands that interrogate and
206 compare objects, and commands that move objects and references between
207 repositories.
208
209
210 Manipulation commands
211 ~~~~~~~~~~~~~~~~~~~~~
212
213 include::cmds-plumbingmanipulators.txt[]
214
215
216 Interrogation commands
217 ~~~~~~~~~~~~~~~~~~~~~~
218
219 include::cmds-plumbinginterrogators.txt[]
220
221 In general, the interrogate commands do not touch the files in
222 the working tree.
223
224
225 Synching repositories
226 ~~~~~~~~~~~~~~~~~~~~~
227
228 include::cmds-synchingrepositories.txt[]
229
230 The following are helper programs used by the above; end users
231 typically do not use them directly.
232
233 include::cmds-synchelpers.txt[]
234
235
236 Internal helper commands
237 ~~~~~~~~~~~~~~~~~~~~~~~~
238
239 These are internal helper commands used by other commands; end
240 users typically do not use them directly.
241
242 include::cmds-purehelpers.txt[]
243
244
245 Configuration Mechanism
246 -----------------------
247
248 Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file
249 is used to hold per-repository configuration options. It is a
250 simple text file modeled after `.ini` format familiar to some
251 people. Here is an example:
252
253 ------------
254 #
255 # A '#' or ';' character indicates a comment.
256 #
257
258 ; core variables
259 [core]
260 ; Don't trust file modes
261 filemode = false
262
263 ; user identity
264 [user]
265 name = "Junio C Hamano"
266 email = "junkio@twinsun.com"
267
268 ------------
269
270 Various commands read from the configuration file and adjust
271 their operation accordingly.
272
273
274 Identifier Terminology
275 ----------------------
276 <object>::
277 Indicates the object name for any type of object.
278
279 <blob>::
280 Indicates a blob object name.
281
282 <tree>::
283 Indicates a tree object name.
284
285 <commit>::
286 Indicates a commit object name.
287
288 <tree-ish>::
289 Indicates a tree, commit or tag object name. A
290 command that takes a <tree-ish> argument ultimately wants to
291 operate on a <tree> object but automatically dereferences
292 <commit> and <tag> objects that point at a <tree>.
293
294 <commit-ish>::
295 Indicates a commit or tag object name. A
296 command that takes a <commit-ish> argument ultimately wants to
297 operate on a <commit> object but automatically dereferences
298 <tag> objects that point at a <commit>.
299
300 <type>::
301 Indicates that an object type is required.
302 Currently one of: `blob`, `tree`, `commit`, or `tag`.
303
304 <file>::
305 Indicates a filename - almost always relative to the
306 root of the tree structure `GIT_INDEX_FILE` describes.
307
308 Symbolic Identifiers
309 --------------------
310 Any git command accepting any <object> can also use the following
311 symbolic notation:
312
313 HEAD::
314 indicates the head of the current branch (i.e. the
315 contents of `$GIT_DIR/HEAD`).
316
317 <tag>::
318 a valid tag 'name'
319 (i.e. the contents of `$GIT_DIR/refs/tags/<tag>`).
320
321 <head>::
322 a valid head 'name'
323 (i.e. the contents of `$GIT_DIR/refs/heads/<head>`).
324
325 For a more complete list of ways to spell object names, see
326 "SPECIFYING REVISIONS" section in gitlink:git-rev-parse[1].
327
328
329 File/Directory Structure
330 ------------------------
331
332 Please see the link:repository-layout.html[repository layout] document.
333
334 Read link:hooks.html[hooks] for more details about each hook.
335
336 Higher level SCMs may provide and manage additional information in the
337 `$GIT_DIR`.
338
339
340 Terminology
341 -----------
342 Please see the link:glossary.html[glossary] document.
343
344
345 Environment Variables
346 ---------------------
347 Various git commands use the following environment variables:
348
349 The git Repository
350 ~~~~~~~~~~~~~~~~~~
351 These environment variables apply to 'all' core git commands. Nb: it
352 is worth noting that they may be used/overridden by SCMS sitting above
353 git so take care if using Cogito etc.
354
355 'GIT_INDEX_FILE'::
356 This environment allows the specification of an alternate
357 index file. If not specified, the default of `$GIT_DIR/index`
358 is used.
359
360 'GIT_OBJECT_DIRECTORY'::
361 If the object storage directory is specified via this
362 environment variable then the sha1 directories are created
363 underneath - otherwise the default `$GIT_DIR/objects`
364 directory is used.
365
366 'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
367 Due to the immutable nature of git objects, old objects can be
368 archived into shared, read-only directories. This variable
369 specifies a ":" separated list of git object directories which
370 can be used to search for git objects. New objects will not be
371 written to these directories.
372
373 'GIT_DIR'::
374 If the 'GIT_DIR' environment variable is set then it
375 specifies a path to use instead of the default `.git`
376 for the base of the repository.
377
378 'GIT_WORK_TREE'::
379 Set the path to the working tree. The value will not be
380 used in combination with repositories found automatically in
381 a .git directory (i.e. $GIT_DIR is not set).
382 This can also be controlled by the '--work-tree' command line
383 option and the core.worktree configuration variable.
384
385 git Commits
386 ~~~~~~~~~~~
387 'GIT_AUTHOR_NAME'::
388 'GIT_AUTHOR_EMAIL'::
389 'GIT_AUTHOR_DATE'::
390 'GIT_COMMITTER_NAME'::
391 'GIT_COMMITTER_EMAIL'::
392 'GIT_COMMITTER_DATE'::
393 'EMAIL'::
394 see gitlink:git-commit-tree[1]
395
396 git Diffs
397 ~~~~~~~~~
398 'GIT_DIFF_OPTS'::
399 Only valid setting is "--unified=??" or "-u??" to set the
400 number of context lines shown when a unified diff is created.
401 This takes precedence over any "-U" or "--unified" option
402 value passed on the git diff command line.
403
404 'GIT_EXTERNAL_DIFF'::
405 When the environment variable 'GIT_EXTERNAL_DIFF' is set, the
406 program named by it is called, instead of the diff invocation
407 described above. For a path that is added, removed, or modified,
408 'GIT_EXTERNAL_DIFF' is called with 7 parameters:
409
410 path old-file old-hex old-mode new-file new-hex new-mode
411 +
412 where:
413
414 <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the
415 contents of <old|new>,
416 <old|new>-hex:: are the 40-hexdigit SHA1 hashes,
417 <old|new>-mode:: are the octal representation of the file modes.
418
419 +
420 The file parameters can point at the user's working file
421 (e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
422 when a new file is added), or a temporary file (e.g. `old-file` in the
423 index). 'GIT_EXTERNAL_DIFF' should not worry about unlinking the
424 temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits.
425 +
426 For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1
427 parameter, <path>.
428
429 other
430 ~~~~~
431 'GIT_MERGE_VERBOSITY'::
432 A number controlling the amount of output shown by
433 the recursive merge strategy. Overrides merge.verbosity.
434 See gitlink:git-merge[1]
435
436 'GIT_PAGER'::
437 This environment variable overrides `$PAGER`. If it is set
438 to an empty string or to the value "cat", git will not launch
439 a pager.
440
441 'GIT_SSH'::
442 If this environment variable is set then gitlink:git-fetch[1]
443 and gitlink:git-push[1] will use this command instead
444 of `ssh` when they need to connect to a remote system.
445 The 'GIT_SSH' command will be given exactly two arguments:
446 the 'username@host' (or just 'host') from the URL and the
447 shell command to execute on that remote system.
448 +
449 To pass options to the program that you want to list in GIT_SSH
450 you will need to wrap the program and options into a shell script,
451 then set GIT_SSH to refer to the shell script.
452 +
453 Usually it is easier to configure any desired options through your
454 personal `.ssh/config` file. Please consult your ssh documentation
455 for further details.
456
457 'GIT_FLUSH'::
458 If this environment variable is set to "1", then commands such
459 as git-blame (in incremental mode), git-rev-list, git-log,
460 git-whatchanged, etc., will force a flush of the output stream
461 after each commit-oriented record have been flushed. If this
462 variable is set to "0", the output of these commands will be done
463 using completely buffered I/O. If this environment variable is
464 not set, git will choose buffered or record-oriented flushing
465 based on whether stdout appears to be redirected to a file or not.
466
467 'GIT_TRACE'::
468 If this variable is set to "1", "2" or "true" (comparison
469 is case insensitive), git will print `trace:` messages on
470 stderr telling about alias expansion, built-in command
471 execution and external command execution.
472 If this variable is set to an integer value greater than 1
473 and lower than 10 (strictly) then git will interpret this
474 value as an open file descriptor and will try to write the
475 trace messages into this file descriptor.
476 Alternatively, if this variable is set to an absolute path
477 (starting with a '/' character), git will interpret this
478 as a file path and will try to write the trace messages
479 into it.
480
481 Discussion[[Discussion]]
482 ------------------------
483
484 More detail on the following is available from the
485 link:user-manual.html#git-concepts[git concepts chapter of the
486 user-manual] and the link:core-tutorial.html[Core tutorial].
487
488 A git project normally consists of a working directory with a ".git"
489 subdirectory at the top level. The .git directory contains, among other
490 things, a compressed object database representing the complete history
491 of the project, an "index" file which links that history to the current
492 contents of the working tree, and named pointers into that history such
493 as tags and branch heads.
494
495 The object database contains objects of three main types: blobs, which
496 hold file data; trees, which point to blobs and other trees to build up
497 directory heirarchies; and commits, which each reference a single tree
498 and some number of parent commits.
499
500 The commit, equivalent to what other systems call a "changeset" or
501 "version", represents a step in the project's history, and each parent
502 represents an immediately preceding step. Commits with more than one
503 parent represent merges of independent lines of development.
504
505 All objects are named by the SHA1 hash of their contents, normally
506 written as a string of 40 hex digits. Such names are globally unique.
507 The entire history leading up to a commit can be vouched for by signing
508 just that commit. A fourth object type, the tag, is provided for this
509 purpose.
510
511 When first created, objects are stored in individual files, but for
512 efficiency may later be compressed together into "pack files".
513
514 Named pointers called refs mark interesting points in history. A ref
515 may contain the SHA1 name of an object or the name of another ref. Refs
516 with names beginning `ref/head/` contain the SHA1 name of the most
517 recent commit (or "head") of a branch under developement. SHA1 names of
518 tags of interest are stored under `ref/tags/`. A special ref named
519 `HEAD` contains the name of the currently checked-out branch.
520
521 The index file is initialized with a list of all paths and, for each
522 path, a blob object and a set of attributes. The blob object represents
523 the contents of the file as of the head of the current branch. The
524 attributes (last modified time, size, etc.) are taken from the
525 corresponding file in the working tree. Subsequent changes to the
526 working tree can be found by comparing these attributes. The index may
527 be updated with new content, and new commits may be created from the
528 content stored in the index.
529
530 The index is also capable of storing multiple entries (called "stages")
531 for a given pathname. These stages are used to hold the various
532 unmerged version of a file when a merge is in progress.
533
534 Authors
535 -------
536 * git's founding father is Linus Torvalds <torvalds@osdl.org>.
537 * The current git nurse is Junio C Hamano <gitster@pobox.com>.
538 * The git potty was written by Andres Ericsson <ae@op5.se>.
539 * General upbringing is handled by the git-list <git@vger.kernel.org>.
540
541 Documentation
542 --------------
543 The documentation for git suite was started by David Greaves
544 <david@dgreaves.com>, and later enhanced greatly by the
545 contributors on the git-list <git@vger.kernel.org>.
546
547 GIT
548 ---
549 Part of the gitlink:git[7] suite