Git 1.7.2-rc1
[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
0b444cdb 18meant for the underlying 'git rev-list' command they use internally
483bc4f0 19and flags and parameters for the other commands they use
0b444cdb 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::
0b444cdb 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
6a5d0b0a 36 that take options themselves.
6e0800ef 37
50325377 38--sq-quote::
0b444cdb 39 Use 'git rev-parse' in shell quoting mode (see SQ-QUOTE
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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
0b444cdb 45 'git rev-list' command.
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46
47--no-revs::
48 Do not output flags and parameters meant for
0b444cdb 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
0b444cdb 77 'git diff-\*'). In contrast to the `--sq-quote` option,
50325377 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
5077fa9c 103--all::
cc1b8d8b 104 Show all refs found in `refs/`.
5077fa9c 105
b09fe971 106--branches[=pattern]::
b09fe971 107--tags[=pattern]::
b09fe971 108--remotes[=pattern]::
e2b53e58 109 Show all branches, tags, or remote-tracking branches,
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110 respectively (i.e., refs found in `refs/heads`,
111 `refs/tags`, or `refs/remotes`, respectively).
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112+
113If a `pattern` is given, only refs matching the given shell glob are
114shown. If the pattern does not contain a globbing character (`?`,
115`\*`, or `[`), it is turned into a prefix match by appending `/\*`.
116
117--glob=pattern::
118 Show all refs matching the shell glob pattern `pattern`. If
119 the pattern does not start with `refs/`, this is automatically
120 prepended. If the pattern does not contain a globbing
121 character (`?`, `\*`, or `[`), it is turned into a prefix
122 match by appending `/\*`.
a62be77f 123
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124--show-toplevel::
125 Show the absolute path of the top-level directory.
126
5077fa9c 127--show-prefix::
5f94c730 128 When the command is invoked from a subdirectory, show the
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129 path of the current directory relative to the top-level
130 directory.
7fc9d69f 131
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132--show-cdup::
133 When the command is invoked from a subdirectory, show the
134 path of the top-level directory relative to the current
135 directory (typically a sequence of "../", or an empty string).
136
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137--git-dir::
138 Show `$GIT_DIR` if defined else show the path to the .git directory.
139
c9bf7be2 140--is-inside-git-dir::
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141 When the current working directory is below the repository
142 directory print "true", otherwise "false".
143
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144--is-inside-work-tree::
145 When the current working directory is inside the work tree of the
146 repository print "true", otherwise "false".
147
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148--is-bare-repository::
149 When the repository is bare print "true", otherwise "false".
c9bf7be2 150
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151--local-env-vars::
152 List the GIT_* environment variables that are local to the
153 repository (e.g. GIT_DIR or GIT_WORK_TREE, but not GIT_EDITOR).
154 Only the names of the variables are listed, not their value,
155 even if they are set.
156
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157--short::
158--short=number::
735d80b3 159 Instead of outputting the full SHA1 values of object names try to
abda1ef5 160 abbreviate them to a shorter unique name. When no length is specified
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161 7 is used. The minimum length is 4.
162
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163--since=datestring::
164--after=datestring::
483bc4f0 165 Parse the date string, and output the corresponding
0b444cdb 166 --max-age= parameter for 'git rev-list'.
a3114b34 167
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168--until=datestring::
169--before=datestring::
483bc4f0 170 Parse the date string, and output the corresponding
0b444cdb 171 --min-age= parameter for 'git rev-list'.
a3114b34 172
7fc9d69f 173<args>...::
5077fa9c 174 Flags and parameters to be parsed.
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175
176
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177SPECIFYING REVISIONS
178--------------------
179
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180A revision parameter typically, but not necessarily, names a
181commit object. They use what is called an 'extended SHA1'
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182syntax. Here are various ways to spell object names. The
183ones listed near the end of this list are to name trees and
184blobs contained in a commit.
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185
186* The full SHA1 object name (40-byte hexadecimal string), or
187 a substring of such that is unique within the repository.
188 E.g. dae86e1950b1277e545cee180551750029cfe735 and dae86e both
189 name the same commit object if there are no other object in
190 your repository whose object name starts with dae86e.
191
0b444cdb 192* An output from 'git describe'; i.e. a closest tag, optionally
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193 followed by a dash and a number of commits, followed by a dash, a
194 `g`, and an abbreviated object name.
6b09c788 195
3a45f625 196* A symbolic ref name. E.g. 'master' typically means the commit
cc1b8d8b 197 object referenced by refs/heads/master. If you
3a45f625 198 happen to have both heads/master and tags/master, you can
72e9340c 199 explicitly say 'heads/master' to tell git which one you mean.
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200 When ambiguous, a `<name>` is disambiguated by taking the
201 first match in the following rules:
3a45f625 202
0ac30568 203 . if `$GIT_DIR/<name>` exists, that is what you mean (this is usually
fd11ae0b 204 useful only for `HEAD`, `FETCH_HEAD`, `ORIG_HEAD` and `MERGE_HEAD`);
0ac30568 205
cc1b8d8b 206 . otherwise, `refs/<name>` if exists;
0ac30568 207
cc1b8d8b 208 . otherwise, `refs/tags/<name>` if exists;
0ac30568 209
cc1b8d8b 210 . otherwise, `refs/heads/<name>` if exists;
0ac30568 211
cc1b8d8b 212 . otherwise, `refs/remotes/<name>` if exists;
0ac30568 213
cc1b8d8b 214 . otherwise, `refs/remotes/<name>/HEAD` if exists.
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215+
216HEAD names the commit your changes in the working tree is based on.
217FETCH_HEAD records the branch you fetched from a remote repository
0b444cdb 218with your last 'git fetch' invocation.
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219ORIG_HEAD is created by commands that moves your HEAD in a drastic
220way, to record the position of the HEAD before their operation, so that
221you can change the tip of the branch back to the state before you ran
222them easily.
223MERGE_HEAD records the commit(s) you are merging into your branch
0b444cdb 224when you run 'git merge'.
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225+
226Note that any of the `refs/*` cases above may come either from
227the `$GIT_DIR/refs` directory or from the `$GIT_DIR/packed-refs` file.
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228
229* A ref followed by the suffix '@' with a date specification
230 enclosed in a brace
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231 pair (e.g. '\{yesterday\}', '\{1 month 2 weeks 3 days 1 hour 1
232 second ago\}' or '\{1979-02-26 18:30:00\}') to specify the value
233 of the ref at a prior point in time. This suffix may only be
234 used immediately following a ref name and the ref must have an
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235 existing log ($GIT_DIR/logs/<ref>). Note that this looks up the state
236 of your *local* ref at a given time; e.g., what was in your local
237 `master` branch last week. If you want to look at commits made during
238 certain times, see `--since` and `--until`.
d556fae2 239
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240* A ref followed by the suffix '@' with an ordinal specification
241 enclosed in a brace pair (e.g. '\{1\}', '\{15\}') to specify
242 the n-th prior value of that ref. For example 'master@\{1\}'
243 is the immediate prior value of 'master' while 'master@\{5\}'
244 is the 5th prior value of 'master'. This suffix may only be used
245 immediately following a ref name and the ref must have an existing
246 log ($GIT_DIR/logs/<ref>).
247
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248* You can use the '@' construct with an empty ref part to get at a
249 reflog of the current branch. For example, if you are on the
250 branch 'blabla', then '@\{1\}' means the same as 'blabla@\{1\}'.
251
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252* The special construct '@\{-<n>\}' means the <n>th branch checked out
253 before the current one.
254
3c651491 255* The suffix '@\{upstream\}' to a ref (short form 'ref@\{u\}') refers to
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256 the branch the ref is set to build on top of. Missing ref defaults
257 to the current branch.
258
b8a6610d 259* A suffix '{caret}' to a revision parameter (e.g. 'HEAD{caret}') means the first parent of
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260 that commit object. '{caret}<n>' means the <n>th parent (i.e.
261 'rev{caret}'
262 is equivalent to 'rev{caret}1'). As a special rule,
263 'rev{caret}0' means the commit itself and is used when 'rev' is the
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264 object name of a tag object that refers to a commit object.
265
54bd2558 266* A suffix '{tilde}<n>' to a revision parameter means the commit
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267 object that is the <n>th generation grand-parent of the named
268 commit object, following only the first parent. I.e. rev~3 is
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269 equivalent to rev{caret}{caret}{caret} which is equivalent to
270 rev{caret}1{caret}1{caret}1. See below for a illustration of
271 the usage of this form.
3a45f625 272
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273* A suffix '{caret}' followed by an object type name enclosed in
274 brace pair (e.g. `v0.99.8{caret}\{commit\}`) means the object
275 could be a tag, and dereference the tag recursively until an
276 object of that type is found or the object cannot be
277 dereferenced anymore (in which case, barf). `rev{caret}0`
278 introduced earlier is a short-hand for `rev{caret}\{commit\}`.
279
280* A suffix '{caret}' followed by an empty brace pair
281 (e.g. `v0.99.8{caret}\{\}`) means the object could be a tag,
282 and dereference the tag recursively until a non-tag object is
283 found.
284
b8a6610d 285* A colon, followed by a slash, followed by a text (e.g. `:/fix nasty bug`): this names
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286 a commit whose commit message starts with the specified text.
287 This name returns the youngest matching commit which is
288 reachable from any ref. If the commit message starts with a
289 '!', you have to repeat that; the special sequence ':/!',
290 followed by something else than '!' is reserved for now.
291
b8a6610d 292* A suffix ':' followed by a path (e.g. `HEAD:README`); this names the blob or tree
6b09c788 293 at the given path in the tree-ish object named by the part
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294 before the colon.
295 ':path' (with an empty part before the colon, e.g. `:README`)
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296 is a special case of the syntax described next: content
297 recorded in the index at the given path.
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298
299* A colon, optionally followed by a stage number (0 to 3) and a
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300 colon, followed by a path (e.g. `:0:README`); this names a blob object in the
301 index at the given path. Missing stage number (and the colon
302 that follows it, e.g. `:README`) names a stage 0 entry. During a merge, stage
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303 1 is the common ancestor, stage 2 is the target branch's version
304 (typically the current branch), and stage 3 is the version from
305 the branch being merged.
6b09c788 306
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307Here is an illustration, by Jon Loeliger. Both commit nodes B
308and C are parents of commit node A. Parent commits are ordered
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309left-to-right.
310
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311........................................
312G H I J
313 \ / \ /
314 D E F
315 \ | / \
316 \ | / |
317 \|/ |
318 B C
319 \ /
320 \ /
321 A
322........................................
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323
324 A = = A^0
325 B = A^ = A^1 = A~1
326 C = A^2 = A^2
327 D = A^^ = A^1^1 = A~2
328 E = B^2 = A^^2
329 F = B^3 = A^^3
330 G = A^^^ = A^1^1^1 = A~3
331 H = D^2 = B^^2 = A^^^2 = A~2^2
332 I = F^ = B^3^ = A^^3^
333 J = F^2 = B^3^2 = A^^3^2
334
3a45f625 335
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336SPECIFYING RANGES
337-----------------
338
0b444cdb 339History traversing commands such as 'git log' operate on a set
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340of commits, not just a single commit. To these commands,
341specifying a single revision with the notation described in the
342previous section means the set of commits reachable from that
343commit, following the commit ancestry chain.
344
345To exclude commits reachable from a commit, a prefix `{caret}`
dcb11263 346notation is used. E.g. `{caret}r1 r2` means commits reachable
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347from `r2` but exclude the ones reachable from `r1`.
348
349This set operation appears so often that there is a shorthand
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350for it. When you have two commits `r1` and `r2` (named according
351to the syntax explained in SPECIFYING REVISIONS above), you can ask
352for commits that are reachable from r2 excluding those that are reachable
dcb11263 353from r1 by `{caret}r1 r2` and it can be written as `r1..r2`.
be4c7014 354
dcb11263 355A similar notation `r1\...r2` is called symmetric difference
be4c7014 356of `r1` and `r2` and is defined as
dcb11263 357`r1 r2 --not $(git merge-base --all r1 r2)`.
e18ee576 358It is the set of commits that are reachable from either one of
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359`r1` or `r2` but not from both.
360
62476c8e 361Two other shorthands for naming a set that is formed by a commit
faf466ff 362and its parent commits exist. The `r1{caret}@` notation means all
62476c8e 363parents of `r1`. `r1{caret}!` includes commit `r1` but excludes
faf466ff 364all of its parents.
62476c8e 365
a5d86f74 366Here are a handful of examples:
be4c7014 367
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368 D G H D
369 D F G H I J D F
370 ^G D H D
371 ^D B E I J F B
372 B...C G H D E B C
373 ^D B C E I J F B C
374 C^@ I J F
375 F^! D G H D F
be4c7014 376
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377PARSEOPT
378--------
379
0b444cdb 380In `--parseopt` mode, 'git rev-parse' helps massaging options to bring to shell
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381scripts the same facilities C builtins have. It works as an option normalizer
382(e.g. splits single switches aggregate values), a bit like `getopt(1)` does.
383
384It takes on the standard input the specification of the options to parse and
385understand, and echoes on the standard output a line suitable for `sh(1)` `eval`
386to replace the arguments with normalized ones. In case of error, it outputs
387usage on the standard error stream, and exits with code 129.
388
389Input Format
390~~~~~~~~~~~~
391
0b444cdb 392'git rev-parse --parseopt' input format is fully text based. It has two parts,
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393separated by a line that contains only `--`. The lines before the separator
394(should be more than one) are used for the usage.
395The lines after the separator describe the options.
396
397Each line of options has this format:
398
399------------
ff962a3f 400<opt_spec><flags>* SP+ help LF
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401------------
402
403`<opt_spec>`::
404 its format is the short option character, then the long option name
405 separated by a comma. Both parts are not required, though at least one
406 is necessary. `h,help`, `dry-run` and `f` are all three correct
407 `<opt_spec>`.
408
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409`<flags>`::
410 `<flags>` are of `*`, `=`, `?` or `!`.
411 * Use `=` if the option takes an argument.
412
413 * Use `?` to mean that the option is optional (though its use is discouraged).
414
415 * Use `*` to mean that this option should not be listed in the usage
416 generated for the `-h` argument. It's shown for `--help-all` as
a5af0e2c 417 documented in linkgit:gitcli[7].
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418
419 * Use `!` to not make the corresponding negated long option available.
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420
421The remainder of the line, after stripping the spaces, is used
422as the help associated to the option.
423
424Blank lines are ignored, and lines that don't match this specification are used
425as option group headers (start the line with a space to create such
426lines on purpose).
427
428Example
429~~~~~~~
430
431------------
432OPTS_SPEC="\
433some-command [options] <args>...
434
435some-command does foo and bar!
436--
437h,help show the help
438
439foo some nifty option --foo
440bar= some cool option --bar with an argument
441
442 An option group Header
443C? option C with an optional argument"
444
b1889c36 445eval `echo "$OPTS_SPEC" | git rev-parse --parseopt -- "$@" || echo exit $?`
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446------------
447
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448SQ-QUOTE
449--------
450
0b444cdb 451In `--sq-quote` mode, 'git rev-parse' echoes on the standard output a
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452single line suitable for `sh(1)` `eval`. This line is made by
453normalizing the arguments following `--sq-quote`. Nothing other than
454quoting the arguments is done.
455
456If you want command input to still be interpreted as usual by
0b444cdb 457'git rev-parse' before the output is shell quoted, see the `--sq`
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458option.
459
460Example
461~~~~~~~
462
463------------
464$ cat >your-git-script.sh <<\EOF
465#!/bin/sh
466args=$(git rev-parse --sq-quote "$@") # quote user-supplied arguments
467command="git frotz -n24 $args" # and use it inside a handcrafted
468 # command line
469eval "$command"
470EOF
471
472$ sh your-git-script.sh "a b'c"
473------------
474
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475EXAMPLES
476--------
477
478* Print the object name of the current commit:
479+
480------------
481$ git rev-parse --verify HEAD
482------------
483
484* Print the commit object name from the revision in the $REV shell variable:
485+
486------------
487$ git rev-parse --verify $REV
488------------
489+
490This will error out if $REV is empty or not a valid revision.
491
492* Same as above:
493+
494------------
495$ git rev-parse --default master --verify $REV
496------------
497+
498but if $REV is empty, the commit object name from master will be printed.
499
21d47835 500
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501Author
502------
21d47835 503Written by Linus Torvalds <torvalds@osdl.org> .
59eb68aa 504Junio C Hamano <gitster@pobox.com> and Pierre Habouzit <madcoder@debian.org>
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505
506Documentation
507--------------
508Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>.
509
510GIT
511---
9e1f0a85 512Part of the linkgit:git[1] suite