git-stash clear: refuse to work with extra parameter for now
[git/git.git] / Documentation / git-rev-parse.txt
CommitLineData
7fc9d69f
JH
1git-rev-parse(1)
2================
3
4NAME
5----
7bd7f280 6git-rev-parse - Pick out and massage parameters
7fc9d69f
JH
7
8
9SYNOPSIS
10--------
11'git-rev-parse' [ --option ] <args>...
12
13DESCRIPTION
14-----------
5077fa9c 15
abda1ef5 16Many git porcelainish commands take mixture of flags
5077fa9c
JH
17(i.e. parameters that begin with a dash '-') and parameters
18meant for underlying `git-rev-list` command they use internally
19and flags and parameters for other commands they use as the
20downstream of `git-rev-list`. This command is used to
21distinguish between them.
7fc9d69f
JH
22
23
24OPTIONS
25-------
21d47835
PH
26--parseopt::
27 Use `git-rev-parse` in option parsing mode (see PARSEOPT section below).
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
5077fa9c
JH
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--sq::
56 Usually the output is made one line per flag and
57 parameter. This option makes output a single line,
58 properly quoted for consumption by shell. Useful when
59 you expect your parameter to contain whitespaces and
60 newlines (e.g. when using pickaxe `-S` with
61 `git-diff-\*`).
62
63--not::
babfaba2
JF
64 When showing object names, prefix them with '{caret}' and
65 strip '{caret}' prefix from the object names that already have
5077fa9c
JH
66 one.
67
68--symbolic::
69 Usually the object names are output in SHA1 form (with
babfaba2 70 possible '{caret}' prefix); this option makes them output in a
5077fa9c
JH
71 form as close to the original input as possible.
72
73
74--all::
75 Show all refs found in `$GIT_DIR/refs`.
76
a62be77f
SE
77--branches::
78 Show branch refs found in `$GIT_DIR/refs/heads`.
79
80--tags::
81 Show tag refs found in `$GIT_DIR/refs/tags`.
82
83--remotes::
84 Show tag refs found in `$GIT_DIR/refs/remotes`.
85
5077fa9c 86--show-prefix::
5f94c730 87 When the command is invoked from a subdirectory, show the
5077fa9c
JH
88 path of the current directory relative to the top-level
89 directory.
7fc9d69f 90
5f94c730
JH
91--show-cdup::
92 When the command is invoked from a subdirectory, show the
93 path of the top-level directory relative to the current
94 directory (typically a sequence of "../", or an empty string).
95
735d80b3
JF
96--git-dir::
97 Show `$GIT_DIR` if defined else show the path to the .git directory.
98
c9bf7be2 99--is-inside-git-dir::
4faac246
ML
100 When the current working directory is below the repository
101 directory print "true", otherwise "false".
102
892c41b9
ML
103--is-inside-work-tree::
104 When the current working directory is inside the work tree of the
105 repository print "true", otherwise "false".
106
493c774e
ML
107--is-bare-repository::
108 When the repository is bare print "true", otherwise "false".
c9bf7be2 109
5102349c 110--short, --short=number::
735d80b3 111 Instead of outputting the full SHA1 values of object names try to
abda1ef5 112 abbreviate them to a shorter unique name. When no length is specified
735d80b3
JF
113 7 is used. The minimum length is 4.
114
a3114b34
JH
115--since=datestring, --after=datestring::
116 Parses the date string, and outputs corresponding
117 --max-age= parameter for git-rev-list command.
118
119--until=datestring, --before=datestring::
120 Parses the date string, and outputs corresponding
121 --min-age= parameter for git-rev-list command.
122
7fc9d69f 123<args>...::
5077fa9c 124 Flags and parameters to be parsed.
7fc9d69f
JH
125
126
3a45f625
JH
127SPECIFYING REVISIONS
128--------------------
129
622ef9df
JH
130A revision parameter typically, but not necessarily, names a
131commit object. They use what is called an 'extended SHA1'
6b09c788
NTND
132syntax. Here are various ways to spell object names. The
133ones listed near the end of this list are to name trees and
134blobs contained in a commit.
3a45f625
JH
135
136* The full SHA1 object name (40-byte hexadecimal string), or
137 a substring of such that is unique within the repository.
138 E.g. dae86e1950b1277e545cee180551750029cfe735 and dae86e both
139 name the same commit object if there are no other object in
140 your repository whose object name starts with dae86e.
141
6b09c788 142* An output from `git-describe`; i.e. a closest tag, followed by a
0ac30568 143 dash, a `g`, and an abbreviated object name.
6b09c788 144
3a45f625
JH
145* A symbolic ref name. E.g. 'master' typically means the commit
146 object referenced by $GIT_DIR/refs/heads/master. If you
147 happen to have both heads/master and tags/master, you can
72e9340c 148 explicitly say 'heads/master' to tell git which one you mean.
0ac30568
JH
149 When ambiguous, a `<name>` is disambiguated by taking the
150 first match in the following rules:
3a45f625 151
0ac30568
JH
152 . if `$GIT_DIR/<name>` exists, that is what you mean (this is usually
153 useful only for `HEAD`, `FETCH_HEAD` and `MERGE_HEAD`);
154
155 . otherwise, `$GIT_DIR/refs/<name>` if exists;
156
157 . otherwise, `$GIT_DIR/refs/tags/<name>` if exists;
158
159 . otherwise, `$GIT_DIR/refs/heads/<name>` if exists;
160
161 . otherwise, `$GIT_DIR/refs/remotes/<name>` if exists;
162
163 . otherwise, `$GIT_DIR/refs/remotes/<name>/HEAD` if exists.
164
165* A ref followed by the suffix '@' with a date specification
166 enclosed in a brace
cce91a2c
SP
167 pair (e.g. '\{yesterday\}', '\{1 month 2 weeks 3 days 1 hour 1
168 second ago\}' or '\{1979-02-26 18:30:00\}') to specify the value
169 of the ref at a prior point in time. This suffix may only be
170 used immediately following a ref name and the ref must have an
171 existing log ($GIT_DIR/logs/<ref>).
d556fae2 172
ee53aff4
SP
173* A ref followed by the suffix '@' with an ordinal specification
174 enclosed in a brace pair (e.g. '\{1\}', '\{15\}') to specify
175 the n-th prior value of that ref. For example 'master@\{1\}'
176 is the immediate prior value of 'master' while 'master@\{5\}'
177 is the 5th prior value of 'master'. This suffix may only be used
178 immediately following a ref name and the ref must have an existing
179 log ($GIT_DIR/logs/<ref>).
180
1e5db307
JS
181* You can use the '@' construct with an empty ref part to get at a
182 reflog of the current branch. For example, if you are on the
183 branch 'blabla', then '@\{1\}' means the same as 'blabla@\{1\}'.
184
babfaba2
JF
185* A suffix '{caret}' to a revision parameter means the first parent of
186 that commit object. '{caret}<n>' means the <n>th parent (i.e.
187 'rev{caret}'
188 is equivalent to 'rev{caret}1'). As a special rule,
189 'rev{caret}0' means the commit itself and is used when 'rev' is the
3a45f625
JH
190 object name of a tag object that refers to a commit object.
191
54bd2558 192* A suffix '{tilde}<n>' to a revision parameter means the commit
3a45f625
JH
193 object that is the <n>th generation grand-parent of the named
194 commit object, following only the first parent. I.e. rev~3 is
0ac30568
JH
195 equivalent to rev{caret}{caret}{caret} which is equivalent to
196 rev{caret}1{caret}1{caret}1. See below for a illustration of
197 the usage of this form.
3a45f625 198
622ef9df
JH
199* A suffix '{caret}' followed by an object type name enclosed in
200 brace pair (e.g. `v0.99.8{caret}\{commit\}`) means the object
201 could be a tag, and dereference the tag recursively until an
202 object of that type is found or the object cannot be
203 dereferenced anymore (in which case, barf). `rev{caret}0`
204 introduced earlier is a short-hand for `rev{caret}\{commit\}`.
205
206* A suffix '{caret}' followed by an empty brace pair
207 (e.g. `v0.99.8{caret}\{\}`) means the object could be a tag,
208 and dereference the tag recursively until a non-tag object is
209 found.
210
28a4d940
JS
211* A colon, followed by a slash, followed by a text: this names
212 a commit whose commit message starts with the specified text.
213 This name returns the youngest matching commit which is
214 reachable from any ref. If the commit message starts with a
215 '!', you have to repeat that; the special sequence ':/!',
216 followed by something else than '!' is reserved for now.
217
6b09c788
NTND
218* A suffix ':' followed by a path; this names the blob or tree
219 at the given path in the tree-ish object named by the part
220 before the colon.
221
222* A colon, optionally followed by a stage number (0 to 3) and a
223 colon, followed by a path; this names a blob object in the
224 index at the given path. Missing stage number (and the colon
257a84d9
SG
225 that follows it) names an stage 0 entry. During a merge, stage
226 1 is the common ancestor, stage 2 is the target branch's version
227 (typically the current branch), and stage 3 is the version from
228 the branch being merged.
6b09c788 229
2be8fd08
JH
230Here is an illustration, by Jon Loeliger. Both node B and C are
231a commit parents of commit node A. Parent commits are ordered
232left-to-right.
233
234 G H I J
235 \ / \ /
236 D E F
f1ec6b22 237 \ | / \
be4c7014
JH
238 \ | / |
239 \|/ |
2be8fd08
JH
240 B C
241 \ /
242 \ /
243 A
244
245 A = = A^0
246 B = A^ = A^1 = A~1
247 C = A^2 = A^2
248 D = A^^ = A^1^1 = A~2
249 E = B^2 = A^^2
250 F = B^3 = A^^3
251 G = A^^^ = A^1^1^1 = A~3
252 H = D^2 = B^^2 = A^^^2 = A~2^2
253 I = F^ = B^3^ = A^^3^
254 J = F^2 = B^3^2 = A^^3^2
255
3a45f625 256
be4c7014
JH
257SPECIFYING RANGES
258-----------------
259
260History traversing commands such as `git-log` operate on a set
261of commits, not just a single commit. To these commands,
262specifying a single revision with the notation described in the
263previous section means the set of commits reachable from that
264commit, following the commit ancestry chain.
265
266To exclude commits reachable from a commit, a prefix `{caret}`
267notation is used. E.g. "`{caret}r1 r2`" means commits reachable
268from `r2` but exclude the ones reachable from `r1`.
269
270This set operation appears so often that there is a shorthand
271for it. "`r1..r2`" is equivalent to "`{caret}r1 r2`". It is
272the difference of two sets (subtract the set of commits
273reachable from `r1` from the set of commits reachable from
274`r2`).
275
276A similar notation "`r1\...r2`" is called symmetric difference
277of `r1` and `r2` and is defined as
278"`r1 r2 --not $(git-merge-base --all r1 r2)`".
e18ee576 279It is the set of commits that are reachable from either one of
be4c7014
JH
280`r1` or `r2` but not from both.
281
62476c8e
JH
282Two other shorthands for naming a set that is formed by a commit
283and its parent commits exists. `r1{caret}@` notation means all
284parents of `r1`. `r1{caret}!` includes commit `r1` but excludes
285its all parents.
286
287Here are a handful examples:
be4c7014 288
c2c6d930
GP
289 D G H D
290 D F G H I J D F
291 ^G D H D
292 ^D B E I J F B
293 B...C G H D E B C
294 ^D B C E I J F B C
295 C^@ I J F
296 F^! D G H D F
be4c7014 297
21d47835
PH
298PARSEOPT
299--------
300
301In `--parseopt` mode, `git-rev-parse` helps massaging options to bring to shell
302scripts the same facilities C builtins have. It works as an option normalizer
303(e.g. splits single switches aggregate values), a bit like `getopt(1)` does.
304
305It takes on the standard input the specification of the options to parse and
306understand, and echoes on the standard output a line suitable for `sh(1)` `eval`
307to replace the arguments with normalized ones. In case of error, it outputs
308usage on the standard error stream, and exits with code 129.
309
310Input Format
311~~~~~~~~~~~~
312
313`git-rev-parse --parseopt` input format is fully text based. It has two parts,
314separated by a line that contains only `--`. The lines before the separator
315(should be more than one) are used for the usage.
316The lines after the separator describe the options.
317
318Each line of options has this format:
319
320------------
321<opt_spec><arg_spec>? SP+ help LF
322------------
323
324`<opt_spec>`::
325 its format is the short option character, then the long option name
326 separated by a comma. Both parts are not required, though at least one
327 is necessary. `h,help`, `dry-run` and `f` are all three correct
328 `<opt_spec>`.
329
330`<arg_spec>`::
331 an `<arg_spec>` tells the option parser if the option has an argument
332 (`=`), an optional one (`?` though its use is discouraged) or none
333 (no `<arg_spec>` in that case).
334
335The remainder of the line, after stripping the spaces, is used
336as the help associated to the option.
337
338Blank lines are ignored, and lines that don't match this specification are used
339as option group headers (start the line with a space to create such
340lines on purpose).
341
342Example
343~~~~~~~
344
345------------
346OPTS_SPEC="\
347some-command [options] <args>...
348
349some-command does foo and bar!
350--
351h,help show the help
352
353foo some nifty option --foo
354bar= some cool option --bar with an argument
355
356 An option group Header
357C? option C with an optional argument"
358
359eval `echo "$OPTS_SPEC" | git-rev-parse --parseopt -- "$@" || echo exit $?`
360------------
361
362
7fc9d69f
JH
363Author
364------
21d47835
PH
365Written by Linus Torvalds <torvalds@osdl.org> .
366Junio C Hamano <junkio@cox.net> and Pierre Habouzit <madcoder@debian.org>
7fc9d69f
JH
367
368Documentation
369--------------
370Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>.
371
372GIT
373---
a7154e91 374Part of the gitlink:git[7] suite