Error in test description of t1200-tutorial
[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--------
11'git-rev-parse' [ --option ] <args>...
12
13DESCRIPTION
14-----------
5077fa9c 15
abda1ef5 16Many git porcelainish commands take mixture of flags
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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.
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22
23
24OPTIONS
25-------
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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::
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57 When showing object names, prefix them with '{caret}' and
58 strip '{caret}' prefix from the object names that already have
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59 one.
60
61--symbolic::
62 Usually the object names are output in SHA1 form (with
babfaba2 63 possible '{caret}' prefix); this option makes them output in a
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64 form as close to the original input as possible.
65
66
67--all::
68 Show all refs found in `$GIT_DIR/refs`.
69
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70--branches::
71 Show branch refs found in `$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
5077fa9c 79--show-prefix::
5f94c730 80 When the command is invoked from a subdirectory, show the
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81 path of the current directory relative to the top-level
82 directory.
7fc9d69f 83
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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
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89--git-dir::
90 Show `$GIT_DIR` if defined else show the path to the .git directory.
91
5102349c 92--short, --short=number::
735d80b3 93 Instead of outputting the full SHA1 values of object names try to
abda1ef5 94 abbreviate them to a shorter unique name. When no length is specified
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95 7 is used. The minimum length is 4.
96
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97--since=datestring, --after=datestring::
98 Parses the date string, and outputs corresponding
99 --max-age= parameter for git-rev-list command.
100
101--until=datestring, --before=datestring::
102 Parses the date string, and outputs corresponding
103 --min-age= parameter for git-rev-list command.
104
7fc9d69f 105<args>...::
5077fa9c 106 Flags and parameters to be parsed.
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107
108
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109SPECIFYING REVISIONS
110--------------------
111
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112A revision parameter typically, but not necessarily, names a
113commit object. They use what is called an 'extended SHA1'
114syntax.
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115
116* The full SHA1 object name (40-byte hexadecimal string), or
117 a substring of such that is unique within the repository.
118 E.g. dae86e1950b1277e545cee180551750029cfe735 and dae86e both
119 name the same commit object if there are no other object in
120 your repository whose object name starts with dae86e.
121
122* A symbolic ref name. E.g. 'master' typically means the commit
123 object referenced by $GIT_DIR/refs/heads/master. If you
124 happen to have both heads/master and tags/master, you can
72e9340c 125 explicitly say 'heads/master' to tell git which one you mean.
3a45f625 126
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127* A suffix '@' followed by a date specification enclosed in a brace
128 pair (e.g. '\{yesterday\}', '\{1 month 2 weeks 3 days 1 hour 1
129 second ago\}' or '\{1979-02-26 18:30:00\}') to specify the value
130 of the ref at a prior point in time. This suffix may only be
131 used immediately following a ref name and the ref must have an
132 existing log ($GIT_DIR/logs/<ref>).
d556fae2 133
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134* A suffix '{caret}' to a revision parameter means the first parent of
135 that commit object. '{caret}<n>' means the <n>th parent (i.e.
136 'rev{caret}'
137 is equivalent to 'rev{caret}1'). As a special rule,
138 'rev{caret}0' means the commit itself and is used when 'rev' is the
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139 object name of a tag object that refers to a commit object.
140
141* A suffix '~<n>' to a revision parameter means the commit
142 object that is the <n>th generation grand-parent of the named
143 commit object, following only the first parent. I.e. rev~3 is
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144 equivalent to rev{caret}{caret}{caret} which is equivalent to\
145 rev{caret}1{caret}1{caret}1.
3a45f625 146
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147* A suffix '{caret}' followed by an object type name enclosed in
148 brace pair (e.g. `v0.99.8{caret}\{commit\}`) means the object
149 could be a tag, and dereference the tag recursively until an
150 object of that type is found or the object cannot be
151 dereferenced anymore (in which case, barf). `rev{caret}0`
152 introduced earlier is a short-hand for `rev{caret}\{commit\}`.
153
154* A suffix '{caret}' followed by an empty brace pair
155 (e.g. `v0.99.8{caret}\{\}`) means the object could be a tag,
156 and dereference the tag recursively until a non-tag object is
157 found.
158
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159Here is an illustration, by Jon Loeliger. Both node B and C are
160a commit parents of commit node A. Parent commits are ordered
161left-to-right.
162
163 G H I J
164 \ / \ /
165 D E F
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166 \ | / \
167 \ | / |
168 \|/ |
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169 B C
170 \ /
171 \ /
172 A
173
174 A = = A^0
175 B = A^ = A^1 = A~1
176 C = A^2 = A^2
177 D = A^^ = A^1^1 = A~2
178 E = B^2 = A^^2
179 F = B^3 = A^^3
180 G = A^^^ = A^1^1^1 = A~3
181 H = D^2 = B^^2 = A^^^2 = A~2^2
182 I = F^ = B^3^ = A^^3^
183 J = F^2 = B^3^2 = A^^3^2
184
3a45f625 185
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186SPECIFYING RANGES
187-----------------
188
189History traversing commands such as `git-log` operate on a set
190of commits, not just a single commit. To these commands,
191specifying a single revision with the notation described in the
192previous section means the set of commits reachable from that
193commit, following the commit ancestry chain.
194
195To exclude commits reachable from a commit, a prefix `{caret}`
196notation is used. E.g. "`{caret}r1 r2`" means commits reachable
197from `r2` but exclude the ones reachable from `r1`.
198
199This set operation appears so often that there is a shorthand
200for it. "`r1..r2`" is equivalent to "`{caret}r1 r2`". It is
201the difference of two sets (subtract the set of commits
202reachable from `r1` from the set of commits reachable from
203`r2`).
204
205A similar notation "`r1\...r2`" is called symmetric difference
206of `r1` and `r2` and is defined as
207"`r1 r2 --not $(git-merge-base --all r1 r2)`".
208It it the set of commits that are reachable from either one of
209`r1` or `r2` but not from both.
210
211Here are a few examples:
212
213 D A B D
214 D F A B C D F
215 ^A G B D
216 ^A F B C F
217 G...I C D F G I
218 ^B G I C D F G I
219
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220Author
221------
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222Written by Linus Torvalds <torvalds@osdl.org> and
223Junio C Hamano <junkio@cox.net>
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224
225Documentation
226--------------
227Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>.
228
229GIT
230---
a7154e91 231Part of the gitlink:git[7] suite
7fc9d69f 232