Add 'git rev-parse --show-toplevel' option.
[git/git.git] / Documentation / git-rev-parse.txt
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1git-rev-parse(1)
2================
3
4NAME
5----
7bd7f280 6git-rev-parse - Pick out and massage parameters
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7
8
9SYNOPSIS
10--------
b1889c36 11'git rev-parse' [ --option ] <args>...
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12
13DESCRIPTION
14-----------
5077fa9c 15
abda1ef5 16Many git porcelainish commands take mixture of flags
5077fa9c 17(i.e. parameters that begin with a dash '-') and parameters
ba020ef5 18meant for the underlying 'git-rev-list' command they use internally
483bc4f0 19and flags and parameters for the other commands they use
ba020ef5 20downstream of 'git-rev-list'. This command is used to
5077fa9c 21distinguish between them.
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22
23
24OPTIONS
25-------
21d47835 26--parseopt::
ba020ef5 27 Use 'git-rev-parse' in option parsing mode (see PARSEOPT section below).
21d47835 28
2163e3f7 29--keep-dashdash::
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30 Only meaningful in `--parseopt` mode. Tells the option parser to echo
31 out the first `--` met instead of skipping it.
32
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33--stop-at-non-option::
34 Only meaningful in `--parseopt` mode. Lets the option parser stop at
35 the first non-option argument. This can be used to parse sub-commands
36 that take options themself.
37
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38--sq-quote::
39 Use 'git-rev-parse' in shell quoting mode (see SQ-QUOTE
40 section below). In contrast to the `--sq` option below, this
41 mode does only quoting. Nothing else is done to command input.
42
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43--revs-only::
44 Do not output flags and parameters not meant for
ba020ef5 45 'git-rev-list' command.
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46
47--no-revs::
48 Do not output flags and parameters meant for
ba020ef5 49 'git-rev-list' command.
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50
51--flags::
52 Do not output non-flag parameters.
53
54--no-flags::
55 Do not output flag parameters.
56
57--default <arg>::
58 If there is no parameter given by the user, use `<arg>`
59 instead.
60
61--verify::
62 The parameter given must be usable as a single, valid
63 object name. Otherwise barf and abort.
64
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65-q::
66--quiet::
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67 Only meaningful in `--verify` mode. Do not output an error
68 message if the first argument is not a valid object name;
69 instead exit with non-zero status silently.
70
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71--sq::
72 Usually the output is made one line per flag and
73 parameter. This option makes output a single line,
74 properly quoted for consumption by shell. Useful when
75 you expect your parameter to contain whitespaces and
76 newlines (e.g. when using pickaxe `-S` with
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77 'git-diff-\*'). In contrast to the `--sq-quote` option,
78 the command input is still interpreted as usual.
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79
80--not::
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81 When showing object names, prefix them with '{caret}' and
82 strip '{caret}' prefix from the object names that already have
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83 one.
84
85--symbolic::
86 Usually the object names are output in SHA1 form (with
babfaba2 87 possible '{caret}' prefix); this option makes them output in a
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88 form as close to the original input as possible.
89
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90--symbolic-full-name::
91 This is similar to \--symbolic, but it omits input that
92 are not refs (i.e. branch or tag names; or more
93 explicitly disambiguating "heads/master" form, when you
94 want to name the "master" branch when there is an
95 unfortunately named tag "master"), and show them as full
96 refnames (e.g. "refs/heads/master").
5077fa9c 97
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98--abbrev-ref[={strict|loose}]::
99 A non-ambiguous short name of the objects name.
100 The option core.warnAmbiguousRefs is used to select the strict
101 abbreviation mode.
102
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103--all::
104 Show all refs found in `$GIT_DIR/refs`.
105
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106--branches::
107 Show branch refs found in `$GIT_DIR/refs/heads`.
108
109--tags::
110 Show tag refs found in `$GIT_DIR/refs/tags`.
111
112--remotes::
113 Show tag refs found in `$GIT_DIR/refs/remotes`.
114
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115--show-toplevel::
116 Show the absolute path of the top-level directory.
117
5077fa9c 118--show-prefix::
5f94c730 119 When the command is invoked from a subdirectory, show the
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120 path of the current directory relative to the top-level
121 directory.
7fc9d69f 122
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123--show-cdup::
124 When the command is invoked from a subdirectory, show the
125 path of the top-level directory relative to the current
126 directory (typically a sequence of "../", or an empty string).
127
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128--git-dir::
129 Show `$GIT_DIR` if defined else show the path to the .git directory.
130
c9bf7be2 131--is-inside-git-dir::
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132 When the current working directory is below the repository
133 directory print "true", otherwise "false".
134
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135--is-inside-work-tree::
136 When the current working directory is inside the work tree of the
137 repository print "true", otherwise "false".
138
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139--is-bare-repository::
140 When the repository is bare print "true", otherwise "false".
c9bf7be2 141
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142--short::
143--short=number::
735d80b3 144 Instead of outputting the full SHA1 values of object names try to
abda1ef5 145 abbreviate them to a shorter unique name. When no length is specified
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146 7 is used. The minimum length is 4.
147
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148--since=datestring::
149--after=datestring::
483bc4f0 150 Parse the date string, and output the corresponding
ba020ef5 151 --max-age= parameter for 'git-rev-list'.
a3114b34 152
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153--until=datestring::
154--before=datestring::
483bc4f0 155 Parse the date string, and output the corresponding
ba020ef5 156 --min-age= parameter for 'git-rev-list'.
a3114b34 157
7fc9d69f 158<args>...::
5077fa9c 159 Flags and parameters to be parsed.
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160
161
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162SPECIFYING REVISIONS
163--------------------
164
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165A revision parameter typically, but not necessarily, names a
166commit object. They use what is called an 'extended SHA1'
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167syntax. Here are various ways to spell object names. The
168ones listed near the end of this list are to name trees and
169blobs contained in a commit.
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170
171* The full SHA1 object name (40-byte hexadecimal string), or
172 a substring of such that is unique within the repository.
173 E.g. dae86e1950b1277e545cee180551750029cfe735 and dae86e both
174 name the same commit object if there are no other object in
175 your repository whose object name starts with dae86e.
176
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177* An output from 'git-describe'; i.e. a closest tag, optionally
178 followed by a dash and a number of commits, followed by a dash, a
179 `g`, and an abbreviated object name.
6b09c788 180
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181* A symbolic ref name. E.g. 'master' typically means the commit
182 object referenced by $GIT_DIR/refs/heads/master. If you
183 happen to have both heads/master and tags/master, you can
72e9340c 184 explicitly say 'heads/master' to tell git which one you mean.
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185 When ambiguous, a `<name>` is disambiguated by taking the
186 first match in the following rules:
3a45f625 187
0ac30568 188 . if `$GIT_DIR/<name>` exists, that is what you mean (this is usually
fd11ae0b 189 useful only for `HEAD`, `FETCH_HEAD`, `ORIG_HEAD` and `MERGE_HEAD`);
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190
191 . otherwise, `$GIT_DIR/refs/<name>` if exists;
192
193 . otherwise, `$GIT_DIR/refs/tags/<name>` if exists;
194
195 . otherwise, `$GIT_DIR/refs/heads/<name>` if exists;
196
197 . otherwise, `$GIT_DIR/refs/remotes/<name>` if exists;
198
199 . otherwise, `$GIT_DIR/refs/remotes/<name>/HEAD` if exists.
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200+
201HEAD names the commit your changes in the working tree is based on.
202FETCH_HEAD records the branch you fetched from a remote repository
203with your last 'git-fetch' invocation.
204ORIG_HEAD is created by commands that moves your HEAD in a drastic
205way, to record the position of the HEAD before their operation, so that
206you can change the tip of the branch back to the state before you ran
207them easily.
208MERGE_HEAD records the commit(s) you are merging into your branch
209when you run 'git-merge'.
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210
211* A ref followed by the suffix '@' with a date specification
212 enclosed in a brace
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213 pair (e.g. '\{yesterday\}', '\{1 month 2 weeks 3 days 1 hour 1
214 second ago\}' or '\{1979-02-26 18:30:00\}') to specify the value
215 of the ref at a prior point in time. This suffix may only be
216 used immediately following a ref name and the ref must have an
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217 existing log ($GIT_DIR/logs/<ref>). Note that this looks up the state
218 of your *local* ref at a given time; e.g., what was in your local
219 `master` branch last week. If you want to look at commits made during
220 certain times, see `--since` and `--until`.
d556fae2 221
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222* A ref followed by the suffix '@' with an ordinal specification
223 enclosed in a brace pair (e.g. '\{1\}', '\{15\}') to specify
224 the n-th prior value of that ref. For example 'master@\{1\}'
225 is the immediate prior value of 'master' while 'master@\{5\}'
226 is the 5th prior value of 'master'. This suffix may only be used
227 immediately following a ref name and the ref must have an existing
228 log ($GIT_DIR/logs/<ref>).
229
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230* You can use the '@' construct with an empty ref part to get at a
231 reflog of the current branch. For example, if you are on the
232 branch 'blabla', then '@\{1\}' means the same as 'blabla@\{1\}'.
233
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234* The special construct '@\{-<n>\}' means the <n>th branch checked out
235 before the current one.
236
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237* A suffix '{caret}' to a revision parameter means the first parent of
238 that commit object. '{caret}<n>' means the <n>th parent (i.e.
239 'rev{caret}'
240 is equivalent to 'rev{caret}1'). As a special rule,
241 'rev{caret}0' means the commit itself and is used when 'rev' is the
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242 object name of a tag object that refers to a commit object.
243
54bd2558 244* A suffix '{tilde}<n>' to a revision parameter means the commit
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245 object that is the <n>th generation grand-parent of the named
246 commit object, following only the first parent. I.e. rev~3 is
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247 equivalent to rev{caret}{caret}{caret} which is equivalent to
248 rev{caret}1{caret}1{caret}1. See below for a illustration of
249 the usage of this form.
3a45f625 250
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251* A suffix '{caret}' followed by an object type name enclosed in
252 brace pair (e.g. `v0.99.8{caret}\{commit\}`) means the object
253 could be a tag, and dereference the tag recursively until an
254 object of that type is found or the object cannot be
255 dereferenced anymore (in which case, barf). `rev{caret}0`
256 introduced earlier is a short-hand for `rev{caret}\{commit\}`.
257
258* A suffix '{caret}' followed by an empty brace pair
259 (e.g. `v0.99.8{caret}\{\}`) means the object could be a tag,
260 and dereference the tag recursively until a non-tag object is
261 found.
262
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263* A colon, followed by a slash, followed by a text: this names
264 a commit whose commit message starts with the specified text.
265 This name returns the youngest matching commit which is
266 reachable from any ref. If the commit message starts with a
267 '!', you have to repeat that; the special sequence ':/!',
268 followed by something else than '!' is reserved for now.
269
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270* A suffix ':' followed by a path; this names the blob or tree
271 at the given path in the tree-ish object named by the part
272 before the colon.
273
274* A colon, optionally followed by a stage number (0 to 3) and a
275 colon, followed by a path; this names a blob object in the
276 index at the given path. Missing stage number (and the colon
a5d86f74 277 that follows it) names a stage 0 entry. During a merge, stage
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278 1 is the common ancestor, stage 2 is the target branch's version
279 (typically the current branch), and stage 3 is the version from
280 the branch being merged.
6b09c788 281
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282Here is an illustration, by Jon Loeliger. Both commit nodes B
283and C are parents of commit node A. Parent commits are ordered
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284left-to-right.
285
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286........................................
287G H I J
288 \ / \ /
289 D E F
290 \ | / \
291 \ | / |
292 \|/ |
293 B C
294 \ /
295 \ /
296 A
297........................................
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298
299 A = = A^0
300 B = A^ = A^1 = A~1
301 C = A^2 = A^2
302 D = A^^ = A^1^1 = A~2
303 E = B^2 = A^^2
304 F = B^3 = A^^3
305 G = A^^^ = A^1^1^1 = A~3
306 H = D^2 = B^^2 = A^^^2 = A~2^2
307 I = F^ = B^3^ = A^^3^
308 J = F^2 = B^3^2 = A^^3^2
309
3a45f625 310
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311SPECIFYING RANGES
312-----------------
313
ba020ef5 314History traversing commands such as 'git-log' operate on a set
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315of commits, not just a single commit. To these commands,
316specifying a single revision with the notation described in the
317previous section means the set of commits reachable from that
318commit, following the commit ancestry chain.
319
320To exclude commits reachable from a commit, a prefix `{caret}`
dcb11263 321notation is used. E.g. `{caret}r1 r2` means commits reachable
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322from `r2` but exclude the ones reachable from `r1`.
323
324This set operation appears so often that there is a shorthand
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325for it. When you have two commits `r1` and `r2` (named according
326to the syntax explained in SPECIFYING REVISIONS above), you can ask
327for commits that are reachable from r2 excluding those that are reachable
dcb11263 328from r1 by `{caret}r1 r2` and it can be written as `r1..r2`.
be4c7014 329
dcb11263 330A similar notation `r1\...r2` is called symmetric difference
be4c7014 331of `r1` and `r2` and is defined as
dcb11263 332`r1 r2 --not $(git merge-base --all r1 r2)`.
e18ee576 333It is the set of commits that are reachable from either one of
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334`r1` or `r2` but not from both.
335
62476c8e 336Two other shorthands for naming a set that is formed by a commit
faf466ff 337and its parent commits exist. The `r1{caret}@` notation means all
62476c8e 338parents of `r1`. `r1{caret}!` includes commit `r1` but excludes
faf466ff 339all of its parents.
62476c8e 340
a5d86f74 341Here are a handful of examples:
be4c7014 342
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343 D G H D
344 D F G H I J D F
345 ^G D H D
346 ^D B E I J F B
347 B...C G H D E B C
348 ^D B C E I J F B C
349 C^@ I J F
350 F^! D G H D F
be4c7014 351
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352PARSEOPT
353--------
354
ba020ef5 355In `--parseopt` mode, 'git-rev-parse' helps massaging options to bring to shell
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356scripts the same facilities C builtins have. It works as an option normalizer
357(e.g. splits single switches aggregate values), a bit like `getopt(1)` does.
358
359It takes on the standard input the specification of the options to parse and
360understand, and echoes on the standard output a line suitable for `sh(1)` `eval`
361to replace the arguments with normalized ones. In case of error, it outputs
362usage on the standard error stream, and exits with code 129.
363
364Input Format
365~~~~~~~~~~~~
366
ba020ef5 367'git-rev-parse --parseopt' input format is fully text based. It has two parts,
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368separated by a line that contains only `--`. The lines before the separator
369(should be more than one) are used for the usage.
370The lines after the separator describe the options.
371
372Each line of options has this format:
373
374------------
ff962a3f 375<opt_spec><flags>* SP+ help LF
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376------------
377
378`<opt_spec>`::
379 its format is the short option character, then the long option name
380 separated by a comma. Both parts are not required, though at least one
381 is necessary. `h,help`, `dry-run` and `f` are all three correct
382 `<opt_spec>`.
383
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384`<flags>`::
385 `<flags>` are of `*`, `=`, `?` or `!`.
386 * Use `=` if the option takes an argument.
387
388 * Use `?` to mean that the option is optional (though its use is discouraged).
389
390 * Use `*` to mean that this option should not be listed in the usage
391 generated for the `-h` argument. It's shown for `--help-all` as
a5af0e2c 392 documented in linkgit:gitcli[7].
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393
394 * Use `!` to not make the corresponding negated long option available.
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395
396The remainder of the line, after stripping the spaces, is used
397as the help associated to the option.
398
399Blank lines are ignored, and lines that don't match this specification are used
400as option group headers (start the line with a space to create such
401lines on purpose).
402
403Example
404~~~~~~~
405
406------------
407OPTS_SPEC="\
408some-command [options] <args>...
409
410some-command does foo and bar!
411--
412h,help show the help
413
414foo some nifty option --foo
415bar= some cool option --bar with an argument
416
417 An option group Header
418C? option C with an optional argument"
419
b1889c36 420eval `echo "$OPTS_SPEC" | git rev-parse --parseopt -- "$@" || echo exit $?`
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421------------
422
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423SQ-QUOTE
424--------
425
426In `--sq-quote` mode, 'git-rev-parse' echoes on the standard output a
427single line suitable for `sh(1)` `eval`. This line is made by
428normalizing the arguments following `--sq-quote`. Nothing other than
429quoting the arguments is done.
430
431If you want command input to still be interpreted as usual by
432'git-rev-parse' before the output is shell quoted, see the `--sq`
433option.
434
435Example
436~~~~~~~
437
438------------
439$ cat >your-git-script.sh <<\EOF
440#!/bin/sh
441args=$(git rev-parse --sq-quote "$@") # quote user-supplied arguments
442command="git frotz -n24 $args" # and use it inside a handcrafted
443 # command line
444eval "$command"
445EOF
446
447$ sh your-git-script.sh "a b'c"
448------------
449
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450EXAMPLES
451--------
452
453* Print the object name of the current commit:
454+
455------------
456$ git rev-parse --verify HEAD
457------------
458
459* Print the commit object name from the revision in the $REV shell variable:
460+
461------------
462$ git rev-parse --verify $REV
463------------
464+
465This will error out if $REV is empty or not a valid revision.
466
467* Same as above:
468+
469------------
470$ git rev-parse --default master --verify $REV
471------------
472+
473but if $REV is empty, the commit object name from master will be printed.
474
21d47835 475
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476Author
477------
21d47835 478Written by Linus Torvalds <torvalds@osdl.org> .
59eb68aa 479Junio C Hamano <gitster@pobox.com> and Pierre Habouzit <madcoder@debian.org>
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480
481Documentation
482--------------
483Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>.
484
485GIT
486---
9e1f0a85 487Part of the linkgit:git[1] suite