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