Merge branch 'kf/askpass-config'
[git/git.git] / Documentation / git.txt
1 git(1)
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]] [--html-path]
13 [-p|--paginate|--no-pager] [--no-replace-objects]
14 [--bare] [--git-dir=GIT_DIR] [--work-tree=GIT_WORK_TREE]
15 [-c name=value]
16 [--help] COMMAND [ARGS]
17
18 DESCRIPTION
19 -----------
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.
23
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
29 introduction.
30
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]).
33
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/`.
37
38 ifdef::stalenotes[]
39 [NOTE]
40 ============
41
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:
46
47 * link:v1.7.2.3/git.html[documentation for release 1.7.2.3]
48
49 * release notes for
50 link:RelNotes-1.7.2.3.txt[1.7.2.3],
51 link:RelNotes-1.7.2.2.txt[1.7.2.2],
52 link:RelNotes-1.7.2.1.txt[1.7.2.1],
53 link:RelNotes-1.7.2.txt[1.7.2].
54
55 * link:v1.7.1.2/git.html[documentation for release 1.7.1.2]
56
57 * release notes for
58 link:RelNotes-1.7.1.2.txt[1.7.1.2],
59 link:RelNotes-1.7.1.1.txt[1.7.1.1],
60 link:RelNotes-1.7.1.txt[1.7.1].
61
62 * link:v1.7.0.7/git.html[documentation for release 1.7.0.7]
63
64 * release notes for
65 link:RelNotes-1.7.0.7.txt[1.7.0.7],
66 link:RelNotes-1.7.0.6.txt[1.7.0.6],
67 link:RelNotes-1.7.0.5.txt[1.7.0.5],
68 link:RelNotes-1.7.0.4.txt[1.7.0.4],
69 link:RelNotes-1.7.0.3.txt[1.7.0.3],
70 link:RelNotes-1.7.0.2.txt[1.7.0.2],
71 link:RelNotes-1.7.0.1.txt[1.7.0.1],
72 link:RelNotes-1.7.0.txt[1.7.0].
73
74 * link:v1.6.6.2/git.html[documentation for release 1.6.6.2]
75
76 * release notes for
77 link:RelNotes-1.6.6.2.txt[1.6.6.2],
78 link:RelNotes-1.6.6.1.txt[1.6.6.1],
79 link:RelNotes-1.6.6.txt[1.6.6].
80
81 * link:v1.6.5.8/git.html[documentation for release 1.6.5.8]
82
83 * release notes for
84 link:RelNotes-1.6.5.8.txt[1.6.5.8],
85 link:RelNotes-1.6.5.7.txt[1.6.5.7],
86 link:RelNotes-1.6.5.6.txt[1.6.5.6],
87 link:RelNotes-1.6.5.5.txt[1.6.5.5],
88 link:RelNotes-1.6.5.4.txt[1.6.5.4],
89 link:RelNotes-1.6.5.3.txt[1.6.5.3],
90 link:RelNotes-1.6.5.2.txt[1.6.5.2],
91 link:RelNotes-1.6.5.1.txt[1.6.5.1],
92 link:RelNotes-1.6.5.txt[1.6.5].
93
94 * link:v1.6.4.4/git.html[documentation for release 1.6.4.4]
95
96 * release notes for
97 link:RelNotes-1.6.4.4.txt[1.6.4.4],
98 link:RelNotes-1.6.4.3.txt[1.6.4.3],
99 link:RelNotes-1.6.4.2.txt[1.6.4.2],
100 link:RelNotes-1.6.4.1.txt[1.6.4.1],
101 link:RelNotes-1.6.4.txt[1.6.4].
102
103 * link:v1.6.3.4/git.html[documentation for release 1.6.3.4]
104
105 * release notes for
106 link:RelNotes-1.6.3.4.txt[1.6.3.4],
107 link:RelNotes-1.6.3.3.txt[1.6.3.3],
108 link:RelNotes-1.6.3.2.txt[1.6.3.2],
109 link:RelNotes-1.6.3.1.txt[1.6.3.1],
110 link:RelNotes-1.6.3.txt[1.6.3].
111
112 * release notes for
113 link:RelNotes-1.6.2.5.txt[1.6.2.5],
114 link:RelNotes-1.6.2.4.txt[1.6.2.4],
115 link:RelNotes-1.6.2.3.txt[1.6.2.3],
116 link:RelNotes-1.6.2.2.txt[1.6.2.2],
117 link:RelNotes-1.6.2.1.txt[1.6.2.1],
118 link:RelNotes-1.6.2.txt[1.6.2].
119
120 * link:v1.6.1.3/git.html[documentation for release 1.6.1.3]
121
122 * release notes for
123 link:RelNotes-1.6.1.3.txt[1.6.1.3],
124 link:RelNotes-1.6.1.2.txt[1.6.1.2],
125 link:RelNotes-1.6.1.1.txt[1.6.1.1],
126 link:RelNotes-1.6.1.txt[1.6.1].
127
128 * link:v1.6.0.6/git.html[documentation for release 1.6.0.6]
129
130 * release notes for
131 link:RelNotes-1.6.0.6.txt[1.6.0.6],
132 link:RelNotes-1.6.0.5.txt[1.6.0.5],
133 link:RelNotes-1.6.0.4.txt[1.6.0.4],
134 link:RelNotes-1.6.0.3.txt[1.6.0.3],
135 link:RelNotes-1.6.0.2.txt[1.6.0.2],
136 link:RelNotes-1.6.0.1.txt[1.6.0.1],
137 link:RelNotes-1.6.0.txt[1.6.0].
138
139 * link:v1.5.6.6/git.html[documentation for release 1.5.6.6]
140
141 * release notes for
142 link:RelNotes-1.5.6.6.txt[1.5.6.6],
143 link:RelNotes-1.5.6.5.txt[1.5.6.5],
144 link:RelNotes-1.5.6.4.txt[1.5.6.4],
145 link:RelNotes-1.5.6.3.txt[1.5.6.3],
146 link:RelNotes-1.5.6.2.txt[1.5.6.2],
147 link:RelNotes-1.5.6.1.txt[1.5.6.1],
148 link:RelNotes-1.5.6.txt[1.5.6].
149
150 * link:v1.5.5.6/git.html[documentation for release 1.5.5.6]
151
152 * release notes for
153 link:RelNotes-1.5.5.6.txt[1.5.5.6],
154 link:RelNotes-1.5.5.5.txt[1.5.5.5],
155 link:RelNotes-1.5.5.4.txt[1.5.5.4],
156 link:RelNotes-1.5.5.3.txt[1.5.5.3],
157 link:RelNotes-1.5.5.2.txt[1.5.5.2],
158 link:RelNotes-1.5.5.1.txt[1.5.5.1],
159 link:RelNotes-1.5.5.txt[1.5.5].
160
161 * link:v1.5.4.7/git.html[documentation for release 1.5.4.7]
162
163 * release notes for
164 link:RelNotes-1.5.4.7.txt[1.5.4.7],
165 link:RelNotes-1.5.4.6.txt[1.5.4.6],
166 link:RelNotes-1.5.4.5.txt[1.5.4.5],
167 link:RelNotes-1.5.4.4.txt[1.5.4.4],
168 link:RelNotes-1.5.4.3.txt[1.5.4.3],
169 link:RelNotes-1.5.4.2.txt[1.5.4.2],
170 link:RelNotes-1.5.4.1.txt[1.5.4.1],
171 link:RelNotes-1.5.4.txt[1.5.4].
172
173 * link:v1.5.3.8/git.html[documentation for release 1.5.3.8]
174
175 * release notes for
176 link:RelNotes-1.5.3.8.txt[1.5.3.8],
177 link:RelNotes-1.5.3.7.txt[1.5.3.7],
178 link:RelNotes-1.5.3.6.txt[1.5.3.6],
179 link:RelNotes-1.5.3.5.txt[1.5.3.5],
180 link:RelNotes-1.5.3.4.txt[1.5.3.4],
181 link:RelNotes-1.5.3.3.txt[1.5.3.3],
182 link:RelNotes-1.5.3.2.txt[1.5.3.2],
183 link:RelNotes-1.5.3.1.txt[1.5.3.1],
184 link:RelNotes-1.5.3.txt[1.5.3].
185
186 * link:v1.5.2.5/git.html[documentation for release 1.5.2.5]
187
188 * release notes for
189 link:RelNotes-1.5.2.5.txt[1.5.2.5],
190 link:RelNotes-1.5.2.4.txt[1.5.2.4],
191 link:RelNotes-1.5.2.3.txt[1.5.2.3],
192 link:RelNotes-1.5.2.2.txt[1.5.2.2],
193 link:RelNotes-1.5.2.1.txt[1.5.2.1],
194 link:RelNotes-1.5.2.txt[1.5.2].
195
196 * link:v1.5.1.6/git.html[documentation for release 1.5.1.6]
197
198 * release notes for
199 link:RelNotes-1.5.1.6.txt[1.5.1.6],
200 link:RelNotes-1.5.1.5.txt[1.5.1.5],
201 link:RelNotes-1.5.1.4.txt[1.5.1.4],
202 link:RelNotes-1.5.1.3.txt[1.5.1.3],
203 link:RelNotes-1.5.1.2.txt[1.5.1.2],
204 link:RelNotes-1.5.1.1.txt[1.5.1.1],
205 link:RelNotes-1.5.1.txt[1.5.1].
206
207 * link:v1.5.0.7/git.html[documentation for release 1.5.0.7]
208
209 * release notes for
210 link:RelNotes-1.5.0.7.txt[1.5.0.7],
211 link:RelNotes-1.5.0.6.txt[1.5.0.6],
212 link:RelNotes-1.5.0.5.txt[1.5.0.5],
213 link:RelNotes-1.5.0.3.txt[1.5.0.3],
214 link:RelNotes-1.5.0.2.txt[1.5.0.2],
215 link:RelNotes-1.5.0.1.txt[1.5.0.1],
216 link:RelNotes-1.5.0.txt[1.5.0].
217
218 * documentation for release link:v1.4.4.4/git.html[1.4.4.4],
219 link:v1.3.3/git.html[1.3.3],
220 link:v1.2.6/git.html[1.2.6],
221 link:v1.0.13/git.html[1.0.13].
222
223 ============
224
225 endif::stalenotes[]
226
227 OPTIONS
228 -------
229 --version::
230 Prints the git suite version that the 'git' program came from.
231
232 --help::
233 Prints the synopsis and a list of the most commonly used
234 commands. If the option '--all' or '-a' is given then all
235 available commands are printed. If a git command is named this
236 option will bring up the manual page for that command.
237 +
238 Other options are available to control how the manual page is
239 displayed. See linkgit:git-help[1] for more information,
240 because `git --help ...` is converted internally into `git
241 help ...`.
242
243 -c <name>=<value>::
244 Pass a configuration parameter to the command. The value
245 given will override values from configuration files.
246 The <name> is expected in the same format as listed by
247 'git config' (subkeys separated by dots).
248
249 --exec-path::
250 Path to wherever your core git programs are installed.
251 This can also be controlled by setting the GIT_EXEC_PATH
252 environment variable. If no path is given, 'git' will print
253 the current setting and then exit.
254
255 --html-path::
256 Print the path to wherever your git HTML documentation is installed
257 and exit.
258
259 -p::
260 --paginate::
261 Pipe all output into 'less' (or if set, $PAGER) if standard
262 output is a terminal. This overrides the `pager.<cmd>`
263 configuration options (see the "Configuration Mechanism" section
264 below).
265
266 --no-pager::
267 Do not pipe git output into a pager.
268
269 --git-dir=<path>::
270 Set the path to the repository. This can also be controlled by
271 setting the GIT_DIR environment variable. It can be an absolute
272 path or relative path to current working directory.
273
274 --work-tree=<path>::
275 Set the path to the working tree. The value will not be
276 used in combination with repositories found automatically in
277 a .git directory (i.e. $GIT_DIR is not set).
278 This can also be controlled by setting the GIT_WORK_TREE
279 environment variable and the core.worktree configuration
280 variable. It can be an absolute path or relative path to
281 the directory specified by --git-dir or GIT_DIR.
282 Note: If --git-dir or GIT_DIR are specified but none of
283 --work-tree, GIT_WORK_TREE and core.worktree is specified,
284 the current working directory is regarded as the top directory
285 of your working tree.
286
287 --bare::
288 Treat the repository as a bare repository. If GIT_DIR
289 environment is not set, it is set to the current working
290 directory.
291
292 --no-replace-objects::
293 Do not use replacement refs to replace git objects. See
294 linkgit:git-replace[1] for more information.
295
296
297 FURTHER DOCUMENTATION
298 ---------------------
299
300 See the references above to get started using git. The following is
301 probably more detail than necessary for a first-time user.
302
303 The link:user-manual.html#git-concepts[git concepts chapter of the
304 user-manual] and linkgit:gitcore-tutorial[7] both provide
305 introductions to the underlying git architecture.
306
307 See linkgit:gitworkflows[7] for an overview of recommended workflows.
308
309 See also the link:howto-index.html[howto] documents for some useful
310 examples.
311
312 The internals are documented in the
313 link:technical/api-index.html[GIT API documentation].
314
315 GIT COMMANDS
316 ------------
317
318 We divide git into high level ("porcelain") commands and low level
319 ("plumbing") commands.
320
321 High-level commands (porcelain)
322 -------------------------------
323
324 We separate the porcelain commands into the main commands and some
325 ancillary user utilities.
326
327 Main porcelain commands
328 ~~~~~~~~~~~~~~~~~~~~~~~
329
330 include::cmds-mainporcelain.txt[]
331
332 Ancillary Commands
333 ~~~~~~~~~~~~~~~~~~
334 Manipulators:
335
336 include::cmds-ancillarymanipulators.txt[]
337
338 Interrogators:
339
340 include::cmds-ancillaryinterrogators.txt[]
341
342
343 Interacting with Others
344 ~~~~~~~~~~~~~~~~~~~~~~~
345
346 These commands are to interact with foreign SCM and with other
347 people via patch over e-mail.
348
349 include::cmds-foreignscminterface.txt[]
350
351
352 Low-level commands (plumbing)
353 -----------------------------
354
355 Although git includes its
356 own porcelain layer, its low-level commands are sufficient to support
357 development of alternative porcelains. Developers of such porcelains
358 might start by reading about linkgit:git-update-index[1] and
359 linkgit:git-read-tree[1].
360
361 The interface (input, output, set of options and the semantics)
362 to these low-level commands are meant to be a lot more stable
363 than Porcelain level commands, because these commands are
364 primarily for scripted use. The interface to Porcelain commands
365 on the other hand are subject to change in order to improve the
366 end user experience.
367
368 The following description divides
369 the low-level commands into commands that manipulate objects (in
370 the repository, index, and working tree), commands that interrogate and
371 compare objects, and commands that move objects and references between
372 repositories.
373
374
375 Manipulation commands
376 ~~~~~~~~~~~~~~~~~~~~~
377
378 include::cmds-plumbingmanipulators.txt[]
379
380
381 Interrogation commands
382 ~~~~~~~~~~~~~~~~~~~~~~
383
384 include::cmds-plumbinginterrogators.txt[]
385
386 In general, the interrogate commands do not touch the files in
387 the working tree.
388
389
390 Synching repositories
391 ~~~~~~~~~~~~~~~~~~~~~
392
393 include::cmds-synchingrepositories.txt[]
394
395 The following are helper commands used by the above; end users
396 typically do not use them directly.
397
398 include::cmds-synchelpers.txt[]
399
400
401 Internal helper commands
402 ~~~~~~~~~~~~~~~~~~~~~~~~
403
404 These are internal helper commands used by other commands; end
405 users typically do not use them directly.
406
407 include::cmds-purehelpers.txt[]
408
409
410 Configuration Mechanism
411 -----------------------
412
413 Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file
414 is used to hold per-repository configuration options. It is a
415 simple text file modeled after `.ini` format familiar to some
416 people. Here is an example:
417
418 ------------
419 #
420 # A '#' or ';' character indicates a comment.
421 #
422
423 ; core variables
424 [core]
425 ; Don't trust file modes
426 filemode = false
427
428 ; user identity
429 [user]
430 name = "Junio C Hamano"
431 email = "junkio@twinsun.com"
432
433 ------------
434
435 Various commands read from the configuration file and adjust
436 their operation accordingly. See linkgit:git-config[1] for a
437 list.
438
439
440 Identifier Terminology
441 ----------------------
442 <object>::
443 Indicates the object name for any type of object.
444
445 <blob>::
446 Indicates a blob object name.
447
448 <tree>::
449 Indicates a tree object name.
450
451 <commit>::
452 Indicates a commit object name.
453
454 <tree-ish>::
455 Indicates a tree, commit or tag object name. A
456 command that takes a <tree-ish> argument ultimately wants to
457 operate on a <tree> object but automatically dereferences
458 <commit> and <tag> objects that point at a <tree>.
459
460 <commit-ish>::
461 Indicates a commit or tag object name. A
462 command that takes a <commit-ish> argument ultimately wants to
463 operate on a <commit> object but automatically dereferences
464 <tag> objects that point at a <commit>.
465
466 <type>::
467 Indicates that an object type is required.
468 Currently one of: `blob`, `tree`, `commit`, or `tag`.
469
470 <file>::
471 Indicates a filename - almost always relative to the
472 root of the tree structure `GIT_INDEX_FILE` describes.
473
474 Symbolic Identifiers
475 --------------------
476 Any git command accepting any <object> can also use the following
477 symbolic notation:
478
479 HEAD::
480 indicates the head of the current branch (i.e. the
481 contents of `$GIT_DIR/HEAD`).
482
483 <tag>::
484 a valid tag 'name'
485 (i.e. the contents of `$GIT_DIR/refs/tags/<tag>`).
486
487 <head>::
488 a valid head 'name'
489 (i.e. the contents of `$GIT_DIR/refs/heads/<head>`).
490
491 For a more complete list of ways to spell object names, see
492 "SPECIFYING REVISIONS" section in linkgit:gitrevisions[1].
493
494
495 File/Directory Structure
496 ------------------------
497
498 Please see the linkgit:gitrepository-layout[5] document.
499
500 Read linkgit:githooks[5] for more details about each hook.
501
502 Higher level SCMs may provide and manage additional information in the
503 `$GIT_DIR`.
504
505
506 Terminology
507 -----------
508 Please see linkgit:gitglossary[7].
509
510
511 Environment Variables
512 ---------------------
513 Various git commands use the following environment variables:
514
515 The git Repository
516 ~~~~~~~~~~~~~~~~~~
517 These environment variables apply to 'all' core git commands. Nb: it
518 is worth noting that they may be used/overridden by SCMS sitting above
519 git so take care if using Cogito etc.
520
521 'GIT_INDEX_FILE'::
522 This environment allows the specification of an alternate
523 index file. If not specified, the default of `$GIT_DIR/index`
524 is used.
525
526 'GIT_OBJECT_DIRECTORY'::
527 If the object storage directory is specified via this
528 environment variable then the sha1 directories are created
529 underneath - otherwise the default `$GIT_DIR/objects`
530 directory is used.
531
532 'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
533 Due to the immutable nature of git objects, old objects can be
534 archived into shared, read-only directories. This variable
535 specifies a ":" separated (on Windows ";" separated) list
536 of git object directories which can be used to search for git
537 objects. New objects will not be written to these directories.
538
539 'GIT_DIR'::
540 If the 'GIT_DIR' environment variable is set then it
541 specifies a path to use instead of the default `.git`
542 for the base of the repository.
543
544 'GIT_WORK_TREE'::
545 Set the path to the working tree. The value will not be
546 used in combination with repositories found automatically in
547 a .git directory (i.e. $GIT_DIR is not set).
548 This can also be controlled by the '--work-tree' command line
549 option and the core.worktree configuration variable.
550
551 'GIT_CEILING_DIRECTORIES'::
552 This should be a colon-separated list of absolute paths.
553 If set, it is a list of directories that git should not chdir
554 up into while looking for a repository directory.
555 It will not exclude the current working directory or
556 a GIT_DIR set on the command line or in the environment.
557 (Useful for excluding slow-loading network directories.)
558
559 'GIT_DISCOVERY_ACROSS_FILESYSTEM'::
560 When run in a directory that does not have ".git" repository
561 directory, git tries to find such a directory in the parent
562 directories to find the top of the working tree, but by default it
563 does not cross filesystem boundaries. This environment variable
564 can be set to true to tell git not to stop at filesystem
565 boundaries. Like 'GIT_CEILING_DIRECTORIES', this will not affect
566 an explicit repository directory set via 'GIT_DIR' or on the
567 command line.
568
569 git Commits
570 ~~~~~~~~~~~
571 'GIT_AUTHOR_NAME'::
572 'GIT_AUTHOR_EMAIL'::
573 'GIT_AUTHOR_DATE'::
574 'GIT_COMMITTER_NAME'::
575 'GIT_COMMITTER_EMAIL'::
576 'GIT_COMMITTER_DATE'::
577 'EMAIL'::
578 see linkgit:git-commit-tree[1]
579
580 git Diffs
581 ~~~~~~~~~
582 'GIT_DIFF_OPTS'::
583 Only valid setting is "--unified=??" or "-u??" to set the
584 number of context lines shown when a unified diff is created.
585 This takes precedence over any "-U" or "--unified" option
586 value passed on the git diff command line.
587
588 'GIT_EXTERNAL_DIFF'::
589 When the environment variable 'GIT_EXTERNAL_DIFF' is set, the
590 program named by it is called, instead of the diff invocation
591 described above. For a path that is added, removed, or modified,
592 'GIT_EXTERNAL_DIFF' is called with 7 parameters:
593
594 path old-file old-hex old-mode new-file new-hex new-mode
595 +
596 where:
597
598 <old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the
599 contents of <old|new>,
600 <old|new>-hex:: are the 40-hexdigit SHA1 hashes,
601 <old|new>-mode:: are the octal representation of the file modes.
602
603 +
604 The file parameters can point at the user's working file
605 (e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
606 when a new file is added), or a temporary file (e.g. `old-file` in the
607 index). 'GIT_EXTERNAL_DIFF' should not worry about unlinking the
608 temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits.
609 +
610 For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1
611 parameter, <path>.
612
613 other
614 ~~~~~
615 'GIT_MERGE_VERBOSITY'::
616 A number controlling the amount of output shown by
617 the recursive merge strategy. Overrides merge.verbosity.
618 See linkgit:git-merge[1]
619
620 'GIT_PAGER'::
621 This environment variable overrides `$PAGER`. If it is set
622 to an empty string or to the value "cat", git will not launch
623 a pager. See also the `core.pager` option in
624 linkgit:git-config[1].
625
626 'GIT_SSH'::
627 If this environment variable is set then 'git fetch'
628 and 'git push' will use this command instead
629 of 'ssh' when they need to connect to a remote system.
630 The '$GIT_SSH' command will be given exactly two arguments:
631 the 'username@host' (or just 'host') from the URL and the
632 shell command to execute on that remote system.
633 +
634 To pass options to the program that you want to list in GIT_SSH
635 you will need to wrap the program and options into a shell script,
636 then set GIT_SSH to refer to the shell script.
637 +
638 Usually it is easier to configure any desired options through your
639 personal `.ssh/config` file. Please consult your ssh documentation
640 for further details.
641
642 'GIT_ASKPASS'::
643 If this environment variable is set, then git commands which need to
644 acquire passwords or passphrases (e.g. for HTTP or IMAP authentication)
645 will call this program with a suitable prompt as command line argument
646 and read the password from its STDOUT. See also the 'core.askpass'
647 option in linkgit:git-config[1].
648
649 'GIT_FLUSH'::
650 If this environment variable is set to "1", then commands such
651 as 'git blame' (in incremental mode), 'git rev-list', 'git log',
652 and 'git whatchanged' will force a flush of the output stream
653 after each commit-oriented record have been flushed. If this
654 variable is set to "0", the output of these commands will be done
655 using completely buffered I/O. If this environment variable is
656 not set, git will choose buffered or record-oriented flushing
657 based on whether stdout appears to be redirected to a file or not.
658
659 'GIT_TRACE'::
660 If this variable is set to "1", "2" or "true" (comparison
661 is case insensitive), git will print `trace:` messages on
662 stderr telling about alias expansion, built-in command
663 execution and external command execution.
664 If this variable is set to an integer value greater than 1
665 and lower than 10 (strictly) then git will interpret this
666 value as an open file descriptor and will try to write the
667 trace messages into this file descriptor.
668 Alternatively, if this variable is set to an absolute path
669 (starting with a '/' character), git will interpret this
670 as a file path and will try to write the trace messages
671 into it.
672
673 Discussion[[Discussion]]
674 ------------------------
675
676 More detail on the following is available from the
677 link:user-manual.html#git-concepts[git concepts chapter of the
678 user-manual] and linkgit:gitcore-tutorial[7].
679
680 A git project normally consists of a working directory with a ".git"
681 subdirectory at the top level. The .git directory contains, among other
682 things, a compressed object database representing the complete history
683 of the project, an "index" file which links that history to the current
684 contents of the working tree, and named pointers into that history such
685 as tags and branch heads.
686
687 The object database contains objects of three main types: blobs, which
688 hold file data; trees, which point to blobs and other trees to build up
689 directory hierarchies; and commits, which each reference a single tree
690 and some number of parent commits.
691
692 The commit, equivalent to what other systems call a "changeset" or
693 "version", represents a step in the project's history, and each parent
694 represents an immediately preceding step. Commits with more than one
695 parent represent merges of independent lines of development.
696
697 All objects are named by the SHA1 hash of their contents, normally
698 written as a string of 40 hex digits. Such names are globally unique.
699 The entire history leading up to a commit can be vouched for by signing
700 just that commit. A fourth object type, the tag, is provided for this
701 purpose.
702
703 When first created, objects are stored in individual files, but for
704 efficiency may later be compressed together into "pack files".
705
706 Named pointers called refs mark interesting points in history. A ref
707 may contain the SHA1 name of an object or the name of another ref. Refs
708 with names beginning `ref/head/` contain the SHA1 name of the most
709 recent commit (or "head") of a branch under development. SHA1 names of
710 tags of interest are stored under `ref/tags/`. A special ref named
711 `HEAD` contains the name of the currently checked-out branch.
712
713 The index file is initialized with a list of all paths and, for each
714 path, a blob object and a set of attributes. The blob object represents
715 the contents of the file as of the head of the current branch. The
716 attributes (last modified time, size, etc.) are taken from the
717 corresponding file in the working tree. Subsequent changes to the
718 working tree can be found by comparing these attributes. The index may
719 be updated with new content, and new commits may be created from the
720 content stored in the index.
721
722 The index is also capable of storing multiple entries (called "stages")
723 for a given pathname. These stages are used to hold the various
724 unmerged version of a file when a merge is in progress.
725
726 Authors
727 -------
728 * git's founding father is Linus Torvalds <torvalds@osdl.org>.
729 * The current git nurse is Junio C Hamano <gitster@pobox.com>.
730 * The git potty was written by Andreas Ericsson <ae@op5.se>.
731 * General upbringing is handled by the git-list <git@vger.kernel.org>.
732
733 Documentation
734 --------------
735 The documentation for git suite was started by David Greaves
736 <david@dgreaves.com>, and later enhanced greatly by the
737 contributors on the git-list <git@vger.kernel.org>.
738
739 Reporting Bugs
740 --------------
741
742 Report bugs to the Git mailing list <git@vger.kernel.org> where the
743 development and maintenance is primarily done. You do not have to be
744 subscribed to the list to send a message there.
745
746 SEE ALSO
747 --------
748 linkgit:gittutorial[7], linkgit:gittutorial-2[7],
749 link:everyday.html[Everyday Git], linkgit:gitcvs-migration[7],
750 linkgit:gitglossary[7], linkgit:gitcore-tutorial[7],
751 linkgit:gitcli[7], link:user-manual.html[The Git User's Manual],
752 linkgit:gitworkflows[7]
753
754 GIT
755 ---
756 Part of the linkgit:git[1] suite