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