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