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