test git rev-parse
[git/git.git] / Documentation / git-rev-parse.txt
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1git-rev-parse(1)
2================
3
4NAME
5----
6git-rev-parse - Pick out and massage parameters
7
8
9SYNOPSIS
10--------
11'git-rev-parse' [ --option ] <args>...
12
13DESCRIPTION
14-----------
15
16Many git porcelainish commands take mixture of flags
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.
22
23
24OPTIONS
25-------
26--revs-only::
27 Do not output flags and parameters not meant for
28 `git-rev-list` command.
29
30--no-revs::
31 Do not output flags and parameters meant for
32 `git-rev-list` command.
33
34--flags::
35 Do not output non-flag parameters.
36
37--no-flags::
38 Do not output flag parameters.
39
40--default <arg>::
41 If there is no parameter given by the user, use `<arg>`
42 instead.
43
44--verify::
45 The parameter given must be usable as a single, valid
46 object name. Otherwise barf and abort.
47
48--sq::
49 Usually the output is made one line per flag and
50 parameter. This option makes output a single line,
51 properly quoted for consumption by shell. Useful when
52 you expect your parameter to contain whitespaces and
53 newlines (e.g. when using pickaxe `-S` with
54 `git-diff-\*`).
55
56--not::
57 When showing object names, prefix them with '{caret}' and
58 strip '{caret}' prefix from the object names that already have
59 one.
60
61--symbolic::
62 Usually the object names are output in SHA1 form (with
63 possible '{caret}' prefix); this option makes them output in a
64 form as close to the original input as possible.
65
66
67--all::
68 Show all refs found in `$GIT_DIR/refs`.
69
70--branches::
71 Show branch refs found in `$GIT_DIR/refs/heads`.
72
73--tags::
74 Show tag refs found in `$GIT_DIR/refs/tags`.
75
76--remotes::
77 Show tag refs found in `$GIT_DIR/refs/remotes`.
78
79--show-prefix::
80 When the command is invoked from a subdirectory, show the
81 path of the current directory relative to the top-level
82 directory.
83
84--show-cdup::
85 When the command is invoked from a subdirectory, show the
86 path of the top-level directory relative to the current
87 directory (typically a sequence of "../", or an empty string).
88
89--git-dir::
90 Show `$GIT_DIR` if defined else show the path to the .git directory.
91
92--is-inside-git-dir::
93 When the current working directory is below the repository
94 directory print "true", otherwise "false".
95
96--is-bare-repository::
97 When the repository is bare print "true", otherwise "false".
98
99--short, --short=number::
100 Instead of outputting the full SHA1 values of object names try to
101 abbreviate them to a shorter unique name. When no length is specified
102 7 is used. The minimum length is 4.
103
104--since=datestring, --after=datestring::
105 Parses the date string, and outputs corresponding
106 --max-age= parameter for git-rev-list command.
107
108--until=datestring, --before=datestring::
109 Parses the date string, and outputs corresponding
110 --min-age= parameter for git-rev-list command.
111
112<args>...::
113 Flags and parameters to be parsed.
114
115
116SPECIFYING REVISIONS
117--------------------
118
119A revision parameter typically, but not necessarily, names a
120commit object. They use what is called an 'extended SHA1'
121syntax. Here are various ways to spell object names. The
122ones listed near the end of this list are to name trees and
123blobs contained in a commit.
124
125* The full SHA1 object name (40-byte hexadecimal string), or
126 a substring of such that is unique within the repository.
127 E.g. dae86e1950b1277e545cee180551750029cfe735 and dae86e both
128 name the same commit object if there are no other object in
129 your repository whose object name starts with dae86e.
130
131* An output from `git-describe`; i.e. a closest tag, followed by a
132 dash, a `g`, and an abbreviated object name.
133
134* A symbolic ref name. E.g. 'master' typically means the commit
135 object referenced by $GIT_DIR/refs/heads/master. If you
136 happen to have both heads/master and tags/master, you can
137 explicitly say 'heads/master' to tell git which one you mean.
138 When ambiguous, a `<name>` is disambiguated by taking the
139 first match in the following rules:
140
141 . if `$GIT_DIR/<name>` exists, that is what you mean (this is usually
142 useful only for `HEAD`, `FETCH_HEAD` and `MERGE_HEAD`);
143
144 . otherwise, `$GIT_DIR/refs/<name>` if exists;
145
146 . otherwise, `$GIT_DIR/refs/tags/<name>` if exists;
147
148 . otherwise, `$GIT_DIR/refs/heads/<name>` if exists;
149
150 . otherwise, `$GIT_DIR/refs/remotes/<name>` if exists;
151
152 . otherwise, `$GIT_DIR/refs/remotes/<name>/HEAD` if exists.
153
154* A ref followed by the suffix '@' with a date specification
155 enclosed in a brace
156 pair (e.g. '\{yesterday\}', '\{1 month 2 weeks 3 days 1 hour 1
157 second ago\}' or '\{1979-02-26 18:30:00\}') to specify the value
158 of the ref at a prior point in time. This suffix may only be
159 used immediately following a ref name and the ref must have an
160 existing log ($GIT_DIR/logs/<ref>).
161
162* A ref followed by the suffix '@' with an ordinal specification
163 enclosed in a brace pair (e.g. '\{1\}', '\{15\}') to specify
164 the n-th prior value of that ref. For example 'master@\{1\}'
165 is the immediate prior value of 'master' while 'master@\{5\}'
166 is the 5th prior value of 'master'. This suffix may only be used
167 immediately following a ref name and the ref must have an existing
168 log ($GIT_DIR/logs/<ref>).
169
170* You can use the '@' construct with an empty ref part to get at a
171 reflog of the current branch. For example, if you are on the
172 branch 'blabla', then '@\{1\}' means the same as 'blabla@\{1\}'.
173
174* A suffix '{caret}' to a revision parameter means the first parent of
175 that commit object. '{caret}<n>' means the <n>th parent (i.e.
176 'rev{caret}'
177 is equivalent to 'rev{caret}1'). As a special rule,
178 'rev{caret}0' means the commit itself and is used when 'rev' is the
179 object name of a tag object that refers to a commit object.
180
181* A suffix '{tilde}<n>' to a revision parameter means the commit
182 object that is the <n>th generation grand-parent of the named
183 commit object, following only the first parent. I.e. rev~3 is
184 equivalent to rev{caret}{caret}{caret} which is equivalent to
185 rev{caret}1{caret}1{caret}1. See below for a illustration of
186 the usage of this form.
187
188* A suffix '{caret}' followed by an object type name enclosed in
189 brace pair (e.g. `v0.99.8{caret}\{commit\}`) means the object
190 could be a tag, and dereference the tag recursively until an
191 object of that type is found or the object cannot be
192 dereferenced anymore (in which case, barf). `rev{caret}0`
193 introduced earlier is a short-hand for `rev{caret}\{commit\}`.
194
195* A suffix '{caret}' followed by an empty brace pair
196 (e.g. `v0.99.8{caret}\{\}`) means the object could be a tag,
197 and dereference the tag recursively until a non-tag object is
198 found.
199
200* A colon, followed by a slash, followed by a text: this names
201 a commit whose commit message starts with the specified text.
202 This name returns the youngest matching commit which is
203 reachable from any ref. If the commit message starts with a
204 '!', you have to repeat that; the special sequence ':/!',
205 followed by something else than '!' is reserved for now.
206
207* A suffix ':' followed by a path; this names the blob or tree
208 at the given path in the tree-ish object named by the part
209 before the colon.
210
211* A colon, optionally followed by a stage number (0 to 3) and a
212 colon, followed by a path; this names a blob object in the
213 index at the given path. Missing stage number (and the colon
214 that follows it) names an stage 0 entry.
215
216Here is an illustration, by Jon Loeliger. Both node B and C are
217a commit parents of commit node A. Parent commits are ordered
218left-to-right.
219
220 G H I J
221 \ / \ /
222 D E F
223 \ | / \
224 \ | / |
225 \|/ |
226 B C
227 \ /
228 \ /
229 A
230
231 A = = A^0
232 B = A^ = A^1 = A~1
233 C = A^2 = A^2
234 D = A^^ = A^1^1 = A~2
235 E = B^2 = A^^2
236 F = B^3 = A^^3
237 G = A^^^ = A^1^1^1 = A~3
238 H = D^2 = B^^2 = A^^^2 = A~2^2
239 I = F^ = B^3^ = A^^3^
240 J = F^2 = B^3^2 = A^^3^2
241
242
243SPECIFYING RANGES
244-----------------
245
246History traversing commands such as `git-log` operate on a set
247of commits, not just a single commit. To these commands,
248specifying a single revision with the notation described in the
249previous section means the set of commits reachable from that
250commit, following the commit ancestry chain.
251
252To exclude commits reachable from a commit, a prefix `{caret}`
253notation is used. E.g. "`{caret}r1 r2`" means commits reachable
254from `r2` but exclude the ones reachable from `r1`.
255
256This set operation appears so often that there is a shorthand
257for it. "`r1..r2`" is equivalent to "`{caret}r1 r2`". It is
258the difference of two sets (subtract the set of commits
259reachable from `r1` from the set of commits reachable from
260`r2`).
261
262A similar notation "`r1\...r2`" is called symmetric difference
263of `r1` and `r2` and is defined as
264"`r1 r2 --not $(git-merge-base --all r1 r2)`".
265It is the set of commits that are reachable from either one of
266`r1` or `r2` but not from both.
267
268Two other shorthands for naming a set that is formed by a commit
269and its parent commits exists. `r1{caret}@` notation means all
270parents of `r1`. `r1{caret}!` includes commit `r1` but excludes
271its all parents.
272
273Here are a handful examples:
274
275 D G H D
276 D F G H I J D F
277 ^G D H D
278 ^D B E I J F B
279 B...C G H D E B C
280 ^D B C E I J F B C
281 C^@ I J F
282 F^! D G H D F
283
284Author
285------
286Written by Linus Torvalds <torvalds@osdl.org> and
287Junio C Hamano <junkio@cox.net>
288
289Documentation
290--------------
291Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>.
292
293GIT
294---
295Part of the gitlink:git[7] suite
296