summaryrefslogtreecommitdiff
path: root/Documentation/git.txt
blob: 35c0c7983d2c18bc0701bc5d6ec22bebc53f792f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
git(1)
======

NAME
----
git - the stupid content tracker


SYNOPSIS
--------
[verse]
'git' [--version] [--exec-path[=GIT_EXEC_PATH]] [--html-path]
    [-p|--paginate|--no-pager] [--no-replace-objects]
    [--bare] [--git-dir=GIT_DIR] [--work-tree=GIT_WORK_TREE]
    [--help] COMMAND [ARGS]

DESCRIPTION
-----------
Git is a fast, scalable, distributed revision control system with an
unusually rich command set that provides both high-level operations
and full access to internals.

See linkgit:gittutorial[7] to get started, then see
link:everyday.html[Everyday Git] for a useful minimum set of commands, and
"man git-commandname" for documentation of each command.  CVS users may
also want to read linkgit:gitcvs-migration[7].  See
the link:user-manual.html[Git User's Manual] for a more in-depth
introduction.

The COMMAND is either a name of a Git command (see below) or an alias
as defined in the configuration file (see linkgit:git-config[1]).

Formatted and hyperlinked version of the latest git
documentation can be viewed at
`http://www.kernel.org/pub/software/scm/git/docs/`.

ifdef::stalenotes[]
[NOTE]
============

You are reading the documentation for the latest (possibly
unreleased) version of git, that is available from 'master'
branch of the `git.git` repository.
Documentation for older releases are available here:

* link:v1.7.0.2/git.html[documentation for release 1.7.0.2]

* release notes for
  link:RelNotes-1.7.0.2.txt[1.7.0.2],
  link:RelNotes-1.7.0.1.txt[1.7.0.1],
  link:RelNotes-1.7.0.txt[1.7.0].

* link:v1.6.6.2/git.html[documentation for release 1.6.6.2]

* release notes for
  link:RelNotes-1.6.6.2.txt[1.6.6.2],
  link:RelNotes-1.6.6.1.txt[1.6.6.1],
  link:RelNotes-1.6.6.txt[1.6.6].

* link:v1.6.5.8/git.html[documentation for release 1.6.5.8]

* release notes for
  link:RelNotes-1.6.5.8.txt[1.6.5.8],
  link:RelNotes-1.6.5.7.txt[1.6.5.7],
  link:RelNotes-1.6.5.6.txt[1.6.5.6],
  link:RelNotes-1.6.5.5.txt[1.6.5.5],
  link:RelNotes-1.6.5.4.txt[1.6.5.4],
  link:RelNotes-1.6.5.3.txt[1.6.5.3],
  link:RelNotes-1.6.5.2.txt[1.6.5.2],
  link:RelNotes-1.6.5.1.txt[1.6.5.1],
  link:RelNotes-1.6.5.txt[1.6.5].

* link:v1.6.4.4/git.html[documentation for release 1.6.4.4]

* release notes for
  link:RelNotes-1.6.4.4.txt[1.6.4.4],
  link:RelNotes-1.6.4.3.txt[1.6.4.3],
  link:RelNotes-1.6.4.2.txt[1.6.4.2],
  link:RelNotes-1.6.4.1.txt[1.6.4.1],
  link:RelNotes-1.6.4.txt[1.6.4].

* link:v1.6.3.4/git.html[documentation for release 1.6.3.4]

* release notes for
  link:RelNotes-1.6.3.4.txt[1.6.3.4],
  link:RelNotes-1.6.3.3.txt[1.6.3.3],
  link:RelNotes-1.6.3.2.txt[1.6.3.2],
  link:RelNotes-1.6.3.1.txt[1.6.3.1],
  link:RelNotes-1.6.3.txt[1.6.3].

* release notes for
  link:RelNotes-1.6.2.5.txt[1.6.2.5],
  link:RelNotes-1.6.2.4.txt[1.6.2.4],
  link:RelNotes-1.6.2.3.txt[1.6.2.3],
  link:RelNotes-1.6.2.2.txt[1.6.2.2],
  link:RelNotes-1.6.2.1.txt[1.6.2.1],
  link:RelNotes-1.6.2.txt[1.6.2].

* link:v1.6.1.3/git.html[documentation for release 1.6.1.3]

* release notes for
  link:RelNotes-1.6.1.3.txt[1.6.1.3],
  link:RelNotes-1.6.1.2.txt[1.6.1.2],
  link:RelNotes-1.6.1.1.txt[1.6.1.1],
  link:RelNotes-1.6.1.txt[1.6.1].

* link:v1.6.0.6/git.html[documentation for release 1.6.0.6]

* release notes for
  link:RelNotes-1.6.0.6.txt[1.6.0.6],
  link:RelNotes-1.6.0.5.txt[1.6.0.5],
  link:RelNotes-1.6.0.4.txt[1.6.0.4],
  link:RelNotes-1.6.0.3.txt[1.6.0.3],
  link:RelNotes-1.6.0.2.txt[1.6.0.2],
  link:RelNotes-1.6.0.1.txt[1.6.0.1],
  link:RelNotes-1.6.0.txt[1.6.0].

* link:v1.5.6.6/git.html[documentation for release 1.5.6.6]

* release notes for
  link:RelNotes-1.5.6.6.txt[1.5.6.6],
  link:RelNotes-1.5.6.5.txt[1.5.6.5],
  link:RelNotes-1.5.6.4.txt[1.5.6.4],
  link:RelNotes-1.5.6.3.txt[1.5.6.3],
  link:RelNotes-1.5.6.2.txt[1.5.6.2],
  link:RelNotes-1.5.6.1.txt[1.5.6.1],
  link:RelNotes-1.5.6.txt[1.5.6].

* link:v1.5.5.6/git.html[documentation for release 1.5.5.6]

* release notes for
  link:RelNotes-1.5.5.6.txt[1.5.5.6],
  link:RelNotes-1.5.5.5.txt[1.5.5.5],
  link:RelNotes-1.5.5.4.txt[1.5.5.4],
  link:RelNotes-1.5.5.3.txt[1.5.5.3],
  link:RelNotes-1.5.5.2.txt[1.5.5.2],
  link:RelNotes-1.5.5.1.txt[1.5.5.1],
  link:RelNotes-1.5.5.txt[1.5.5].

* link:v1.5.4.7/git.html[documentation for release 1.5.4.7]

* release notes for
  link:RelNotes-1.5.4.7.txt[1.5.4.7],
  link:RelNotes-1.5.4.6.txt[1.5.4.6],
  link:RelNotes-1.5.4.5.txt[1.5.4.5],
  link:RelNotes-1.5.4.4.txt[1.5.4.4],
  link:RelNotes-1.5.4.3.txt[1.5.4.3],
  link:RelNotes-1.5.4.2.txt[1.5.4.2],
  link:RelNotes-1.5.4.1.txt[1.5.4.1],
  link:RelNotes-1.5.4.txt[1.5.4].

* link:v1.5.3.8/git.html[documentation for release 1.5.3.8]

* release notes for
  link:RelNotes-1.5.3.8.txt[1.5.3.8],
  link:RelNotes-1.5.3.7.txt[1.5.3.7],
  link:RelNotes-1.5.3.6.txt[1.5.3.6],
  link:RelNotes-1.5.3.5.txt[1.5.3.5],
  link:RelNotes-1.5.3.4.txt[1.5.3.4],
  link:RelNotes-1.5.3.3.txt[1.5.3.3],
  link:RelNotes-1.5.3.2.txt[1.5.3.2],
  link:RelNotes-1.5.3.1.txt[1.5.3.1],
  link:RelNotes-1.5.3.txt[1.5.3].

* link:v1.5.2.5/git.html[documentation for release 1.5.2.5]

* release notes for
  link:RelNotes-1.5.2.5.txt[1.5.2.5],
  link:RelNotes-1.5.2.4.txt[1.5.2.4],
  link:RelNotes-1.5.2.3.txt[1.5.2.3],
  link:RelNotes-1.5.2.2.txt[1.5.2.2],
  link:RelNotes-1.5.2.1.txt[1.5.2.1],
  link:RelNotes-1.5.2.txt[1.5.2].

* link:v1.5.1.6/git.html[documentation for release 1.5.1.6]

* release notes for
  link:RelNotes-1.5.1.6.txt[1.5.1.6],
  link:RelNotes-1.5.1.5.txt[1.5.1.5],
  link:RelNotes-1.5.1.4.txt[1.5.1.4],
  link:RelNotes-1.5.1.3.txt[1.5.1.3],
  link:RelNotes-1.5.1.2.txt[1.5.1.2],
  link:RelNotes-1.5.1.1.txt[1.5.1.1],
  link:RelNotes-1.5.1.txt[1.5.1].

* link:v1.5.0.7/git.html[documentation for release 1.5.0.7]

* release notes for
  link:RelNotes-1.5.0.7.txt[1.5.0.7],
  link:RelNotes-1.5.0.6.txt[1.5.0.6],
  link:RelNotes-1.5.0.5.txt[1.5.0.5],
  link:RelNotes-1.5.0.3.txt[1.5.0.3],
  link:RelNotes-1.5.0.2.txt[1.5.0.2],
  link:RelNotes-1.5.0.1.txt[1.5.0.1],
  link:RelNotes-1.5.0.txt[1.5.0].

* documentation for release link:v1.4.4.4/git.html[1.4.4.4],
  link:v1.3.3/git.html[1.3.3],
  link:v1.2.6/git.html[1.2.6],
  link:v1.0.13/git.html[1.0.13].

============

endif::stalenotes[]

OPTIONS
-------
--version::
	Prints the git suite version that the 'git' program came from.

--help::
	Prints the synopsis and a list of the most commonly used
	commands. If the option '--all' or '-a' is given then all
	available commands are printed. If a git command is named this
	option will bring up the manual page for that command.
+
Other options are available to control how the manual page is
displayed. See linkgit:git-help[1] for more information,
because `git --help ...` is converted internally into `git
help ...`.

--exec-path::
	Path to wherever your core git programs are installed.
	This can also be controlled by setting the GIT_EXEC_PATH
	environment variable. If no path is given, 'git' will print
	the current setting and then exit.

--html-path::
	Print the path to wherever your git HTML documentation is installed
	and exit.

-p::
--paginate::
	Pipe all output into 'less' (or if set, $PAGER) if standard
	output is a terminal.  This overrides the `pager.<cmd>`
	configuration options (see the "Configuration Mechanism" section
	below).

--no-pager::
	Do not pipe git output into a pager.

--git-dir=<path>::
	Set the path to the repository. This can also be controlled by
	setting the GIT_DIR environment variable. It can be an absolute
	path or relative path to current working directory.

--work-tree=<path>::
	Set the path to the working tree.  The value will not be
	used in combination with repositories found automatically in
	a .git directory (i.e. $GIT_DIR is not set).
	This can also be controlled by setting the GIT_WORK_TREE
	environment variable and the core.worktree configuration
	variable. It can be an absolute path or relative path to
	the directory specified by --git-dir or GIT_DIR.
	Note: If --git-dir or GIT_DIR are specified but none of
	--work-tree, GIT_WORK_TREE and core.worktree is specified,
	the current working directory is regarded as the top directory
	of your working tree.

--bare::
	Treat the repository as a bare repository.  If GIT_DIR
	environment is not set, it is set to the current working
	directory.

--no-replace-objects::
	Do not use replacement refs to replace git objects. See
	linkgit:git-replace[1] for more information.


FURTHER DOCUMENTATION
---------------------

See the references above to get started using git.  The following is
probably more detail than necessary for a first-time user.

The link:user-manual.html#git-concepts[git concepts chapter of the
user-manual] and linkgit:gitcore-tutorial[7] both provide
introductions to the underlying git architecture.

See linkgit:gitworkflows[7] for an overview of recommended workflows.

See also the link:howto-index.html[howto] documents for some useful
examples.

The internals are documented in the
link:technical/api-index.html[GIT API documentation].

GIT COMMANDS
------------

We divide git into high level ("porcelain") commands and low level
("plumbing") commands.

High-level commands (porcelain)
-------------------------------

We separate the porcelain commands into the main commands and some
ancillary user utilities.

Main porcelain commands
~~~~~~~~~~~~~~~~~~~~~~~

include::cmds-mainporcelain.txt[]

Ancillary Commands
~~~~~~~~~~~~~~~~~~
Manipulators:

include::cmds-ancillarymanipulators.txt[]

Interrogators:

include::cmds-ancillaryinterrogators.txt[]


Interacting with Others
~~~~~~~~~~~~~~~~~~~~~~~

These commands are to interact with foreign SCM and with other
people via patch over e-mail.

include::cmds-foreignscminterface.txt[]


Low-level commands (plumbing)
-----------------------------

Although git includes its
own porcelain layer, its low-level commands are sufficient to support
development of alternative porcelains.  Developers of such porcelains
might start by reading about linkgit:git-update-index[1] and
linkgit:git-read-tree[1].

The interface (input, output, set of options and the semantics)
to these low-level commands are meant to be a lot more stable
than Porcelain level commands, because these commands are
primarily for scripted use.  The interface to Porcelain commands
on the other hand are subject to change in order to improve the
end user experience.

The following description divides
the low-level commands into commands that manipulate objects (in
the repository, index, and working tree), commands that interrogate and
compare objects, and commands that move objects and references between
repositories.


Manipulation commands
~~~~~~~~~~~~~~~~~~~~~

include::cmds-plumbingmanipulators.txt[]


Interrogation commands
~~~~~~~~~~~~~~~~~~~~~~

include::cmds-plumbinginterrogators.txt[]

In general, the interrogate commands do not touch the files in
the working tree.


Synching repositories
~~~~~~~~~~~~~~~~~~~~~

include::cmds-synchingrepositories.txt[]

The following are helper commands used by the above; end users
typically do not use them directly.

include::cmds-synchelpers.txt[]


Internal helper commands
~~~~~~~~~~~~~~~~~~~~~~~~

These are internal helper commands used by other commands; end
users typically do not use them directly.

include::cmds-purehelpers.txt[]


Configuration Mechanism
-----------------------

Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file
is used to hold per-repository configuration options.  It is a
simple text file modeled after `.ini` format familiar to some
people.  Here is an example:

------------
#
# A '#' or ';' character indicates a comment.
#

; core variables
[core]
	; Don't trust file modes
	filemode = false

; user identity
[user]
	name = "Junio C Hamano"
	email = "junkio@twinsun.com"

------------

Various commands read from the configuration file and adjust
their operation accordingly.  See linkgit:git-config[1] for a
list.


Identifier Terminology
----------------------
<object>::
	Indicates the object name for any type of object.

<blob>::
	Indicates a blob object name.

<tree>::
	Indicates a tree object name.

<commit>::
	Indicates a commit object name.

<tree-ish>::
	Indicates a tree, commit or tag object name.  A
	command that takes a <tree-ish> argument ultimately wants to
	operate on a <tree> object but automatically dereferences
	<commit> and <tag> objects that point at a <tree>.

<commit-ish>::
	Indicates a commit or tag object name.  A
	command that takes a <commit-ish> argument ultimately wants to
	operate on a <commit> object but automatically dereferences
	<tag> objects that point at a <commit>.

<type>::
	Indicates that an object type is required.
	Currently one of: `blob`, `tree`, `commit`, or `tag`.

<file>::
	Indicates a filename - almost always relative to the
	root of the tree structure `GIT_INDEX_FILE` describes.

Symbolic Identifiers
--------------------
Any git command accepting any <object> can also use the following
symbolic notation:

HEAD::
	indicates the head of the current branch (i.e. the
	contents of `$GIT_DIR/HEAD`).

<tag>::
	a valid tag 'name'
	(i.e. the contents of `$GIT_DIR/refs/tags/<tag>`).

<head>::
	a valid head 'name'
	(i.e. the contents of `$GIT_DIR/refs/heads/<head>`).

For a more complete list of ways to spell object names, see
"SPECIFYING REVISIONS" section in linkgit:git-rev-parse[1].


File/Directory Structure
------------------------

Please see the linkgit:gitrepository-layout[5] document.

Read linkgit:githooks[5] for more details about each hook.

Higher level SCMs may provide and manage additional information in the
`$GIT_DIR`.


Terminology
-----------
Please see linkgit:gitglossary[7].


Environment Variables
---------------------
Various git commands use the following environment variables:

The git Repository
~~~~~~~~~~~~~~~~~~
These environment variables apply to 'all' core git commands. Nb: it
is worth noting that they may be used/overridden by SCMS sitting above
git so take care if using Cogito etc.

'GIT_INDEX_FILE'::
	This environment allows the specification of an alternate
	index file. If not specified, the default of `$GIT_DIR/index`
	is used.

'GIT_OBJECT_DIRECTORY'::
	If the object storage directory is specified via this
	environment variable then the sha1 directories are created
	underneath - otherwise the default `$GIT_DIR/objects`
	directory is used.

'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
	Due to the immutable nature of git objects, old objects can be
	archived into shared, read-only directories. This variable
	specifies a ":" separated (on Windows ";" separated) list
	of git object directories which can be used to search for git
	objects. New objects will not be written to these directories.

'GIT_DIR'::
	If the 'GIT_DIR' environment variable is set then it
	specifies a path to use instead of the default `.git`
	for the base of the repository.

'GIT_WORK_TREE'::
	Set the path to the working tree.  The value will not be
	used in combination with repositories found automatically in
	a .git directory (i.e. $GIT_DIR is not set).
	This can also be controlled by the '--work-tree' command line
	option and the core.worktree configuration variable.

'GIT_CEILING_DIRECTORIES'::
	This should be a colon-separated list of absolute paths.
	If set, it is a list of directories that git should not chdir
	up into while looking for a repository directory.
	It will not exclude the current working directory or
	a GIT_DIR set on the command line or in the environment.
	(Useful for excluding slow-loading network directories.)

git Commits
~~~~~~~~~~~
'GIT_AUTHOR_NAME'::
'GIT_AUTHOR_EMAIL'::
'GIT_AUTHOR_DATE'::
'GIT_COMMITTER_NAME'::
'GIT_COMMITTER_EMAIL'::
'GIT_COMMITTER_DATE'::
'EMAIL'::
	see linkgit:git-commit-tree[1]

git Diffs
~~~~~~~~~
'GIT_DIFF_OPTS'::
	Only valid setting is "--unified=??" or "-u??" to set the
	number of context lines shown when a unified diff is created.
	This takes precedence over any "-U" or "--unified" option
	value passed on the git diff command line.

'GIT_EXTERNAL_DIFF'::
	When the environment variable 'GIT_EXTERNAL_DIFF' is set, the
	program named by it is called, instead of the diff invocation
	described above.  For a path that is added, removed, or modified,
        'GIT_EXTERNAL_DIFF' is called with 7 parameters:

	path old-file old-hex old-mode new-file new-hex new-mode
+
where:

	<old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the
                         contents of <old|new>,
	<old|new>-hex:: are the 40-hexdigit SHA1 hashes,
	<old|new>-mode:: are the octal representation of the file modes.

+
The file parameters can point at the user's working file
(e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
when a new file is added), or a temporary file (e.g. `old-file` in the
index).  'GIT_EXTERNAL_DIFF' should not worry about unlinking the
temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits.
+
For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1
parameter, <path>.

other
~~~~~
'GIT_MERGE_VERBOSITY'::
	A number controlling the amount of output shown by
	the recursive merge strategy.  Overrides merge.verbosity.
	See linkgit:git-merge[1]

'GIT_PAGER'::
	This environment variable overrides `$PAGER`. If it is set
	to an empty string or to the value "cat", git will not launch
	a pager.  See also the `core.pager` option in
	linkgit:git-config[1].

'GIT_SSH'::
	If this environment variable is set then 'git fetch'
	and 'git push' will use this command instead
	of 'ssh' when they need to connect to a remote system.
	The '$GIT_SSH' command will be given exactly two arguments:
	the 'username@host' (or just 'host') from the URL and the
	shell command to execute on that remote system.
+
To pass options to the program that you want to list in GIT_SSH
you will need to wrap the program and options into a shell script,
then set GIT_SSH to refer to the shell script.
+
Usually it is easier to configure any desired options through your
personal `.ssh/config` file.  Please consult your ssh documentation
for further details.

'GIT_FLUSH'::
	If this environment variable is set to "1", then commands such
	as 'git blame' (in incremental mode), 'git rev-list', 'git log',
	and 'git whatchanged' will force a flush of the output stream
	after each commit-oriented record have been flushed.   If this
	variable is set to "0", the output of these commands will be done
	using completely buffered I/O.   If this environment variable is
	not set, git will choose buffered or record-oriented flushing
	based on whether stdout appears to be redirected to a file or not.

'GIT_TRACE'::
	If this variable is set to "1", "2" or "true" (comparison
	is case insensitive), git will print `trace:` messages on
	stderr telling about alias expansion, built-in command
	execution and external command execution.
	If this variable is set to an integer value greater than 1
	and lower than 10 (strictly) then git will interpret this
	value as an open file descriptor and will try to write the
	trace messages into this file descriptor.
	Alternatively, if this variable is set to an absolute path
	(starting with a '/' character), git will interpret this
	as a file path and will try to write the trace messages
	into it.

Discussion[[Discussion]]
------------------------

More detail on the following is available from the
link:user-manual.html#git-concepts[git concepts chapter of the
user-manual] and linkgit:gitcore-tutorial[7].

A git project normally consists of a working directory with a ".git"
subdirectory at the top level.  The .git directory contains, among other
things, a compressed object database representing the complete history
of the project, an "index" file which links that history to the current
contents of the working tree, and named pointers into that history such
as tags and branch heads.

The object database contains objects of three main types: blobs, which
hold file data; trees, which point to blobs and other trees to build up
directory hierarchies; and commits, which each reference a single tree
and some number of parent commits.

The commit, equivalent to what other systems call a "changeset" or
"version", represents a step in the project's history, and each parent
represents an immediately preceding step.  Commits with more than one
parent represent merges of independent lines of development.

All objects are named by the SHA1 hash of their contents, normally
written as a string of 40 hex digits.  Such names are globally unique.
The entire history leading up to a commit can be vouched for by signing
just that commit.  A fourth object type, the tag, is provided for this
purpose.

When first created, objects are stored in individual files, but for
efficiency may later be compressed together into "pack files".

Named pointers called refs mark interesting points in history.  A ref
may contain the SHA1 name of an object or the name of another ref.  Refs
with names beginning `ref/head/` contain the SHA1 name of the most
recent commit (or "head") of a branch under development.  SHA1 names of
tags of interest are stored under `ref/tags/`.  A special ref named
`HEAD` contains the name of the currently checked-out branch.

The index file is initialized with a list of all paths and, for each
path, a blob object and a set of attributes.  The blob object represents
the contents of the file as of the head of the current branch.  The
attributes (last modified time, size, etc.) are taken from the
corresponding file in the working tree.  Subsequent changes to the
working tree can be found by comparing these attributes.  The index may
be updated with new content, and new commits may be created from the
content stored in the index.

The index is also capable of storing multiple entries (called "stages")
for a given pathname.  These stages are used to hold the various
unmerged version of a file when a merge is in progress.

Authors
-------
* git's founding father is Linus Torvalds <torvalds@osdl.org>.
* The current git nurse is Junio C Hamano <gitster@pobox.com>.
* The git potty was written by Andreas Ericsson <ae@op5.se>.
* General upbringing is handled by the git-list <git@vger.kernel.org>.

Documentation
--------------
The documentation for git suite was started by David Greaves
<david@dgreaves.com>, and later enhanced greatly by the
contributors on the git-list <git@vger.kernel.org>.

SEE ALSO
--------
linkgit:gittutorial[7], linkgit:gittutorial-2[7],
link:everyday.html[Everyday Git], linkgit:gitcvs-migration[7],
linkgit:gitglossary[7], linkgit:gitcore-tutorial[7],
linkgit:gitcli[7], link:user-manual.html[The Git User's Manual],
linkgit:gitworkflows[7]

GIT
---
Part of the linkgit:git[1] suite