diff-format.txt: Combined diff format documentation supplement
[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'
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114syntax. Here are various ways to spell object names. The
115ones listed near the end of this list are to name trees and
116blobs contained in a commit.
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117
118* The full SHA1 object name (40-byte hexadecimal string), or
119 a substring of such that is unique within the repository.
120 E.g. dae86e1950b1277e545cee180551750029cfe735 and dae86e both
121 name the same commit object if there are no other object in
122 your repository whose object name starts with dae86e.
123
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124* An output from `git-describe`; i.e. a closest tag, followed by a
125 dash, a 'g', and an abbreviated object name.
126
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127* A symbolic ref name. E.g. 'master' typically means the commit
128 object referenced by $GIT_DIR/refs/heads/master. If you
129 happen to have both heads/master and tags/master, you can
72e9340c 130 explicitly say 'heads/master' to tell git which one you mean.
3a45f625 131
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132* A suffix '@' followed by a date specification enclosed in a brace
133 pair (e.g. '\{yesterday\}', '\{1 month 2 weeks 3 days 1 hour 1
134 second ago\}' or '\{1979-02-26 18:30:00\}') to specify the value
135 of the ref at a prior point in time. This suffix may only be
136 used immediately following a ref name and the ref must have an
137 existing log ($GIT_DIR/logs/<ref>).
d556fae2 138
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139* A suffix '{caret}' to a revision parameter means the first parent of
140 that commit object. '{caret}<n>' means the <n>th parent (i.e.
141 'rev{caret}'
142 is equivalent to 'rev{caret}1'). As a special rule,
143 'rev{caret}0' means the commit itself and is used when 'rev' is the
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144 object name of a tag object that refers to a commit object.
145
54bd2558 146* A suffix '{tilde}<n>' to a revision parameter means the commit
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147 object that is the <n>th generation grand-parent of the named
148 commit object, following only the first parent. I.e. rev~3 is
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149 equivalent to rev{caret}{caret}{caret} which is equivalent to\
150 rev{caret}1{caret}1{caret}1.
3a45f625 151
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152* A suffix '{caret}' followed by an object type name enclosed in
153 brace pair (e.g. `v0.99.8{caret}\{commit\}`) means the object
154 could be a tag, and dereference the tag recursively until an
155 object of that type is found or the object cannot be
156 dereferenced anymore (in which case, barf). `rev{caret}0`
157 introduced earlier is a short-hand for `rev{caret}\{commit\}`.
158
159* A suffix '{caret}' followed by an empty brace pair
160 (e.g. `v0.99.8{caret}\{\}`) means the object could be a tag,
161 and dereference the tag recursively until a non-tag object is
162 found.
163
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164* A suffix ':' followed by a path; this names the blob or tree
165 at the given path in the tree-ish object named by the part
166 before the colon.
167
168* A colon, optionally followed by a stage number (0 to 3) and a
169 colon, followed by a path; this names a blob object in the
170 index at the given path. Missing stage number (and the colon
171 that follows it) names an stage 0 entry.
172
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173Here is an illustration, by Jon Loeliger. Both node B and C are
174a commit parents of commit node A. Parent commits are ordered
175left-to-right.
176
177 G H I J
178 \ / \ /
179 D E F
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180 \ | / \
181 \ | / |
182 \|/ |
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183 B C
184 \ /
185 \ /
186 A
187
188 A = = A^0
189 B = A^ = A^1 = A~1
190 C = A^2 = A^2
191 D = A^^ = A^1^1 = A~2
192 E = B^2 = A^^2
193 F = B^3 = A^^3
194 G = A^^^ = A^1^1^1 = A~3
195 H = D^2 = B^^2 = A^^^2 = A~2^2
196 I = F^ = B^3^ = A^^3^
197 J = F^2 = B^3^2 = A^^3^2
198
3a45f625 199
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200SPECIFYING RANGES
201-----------------
202
203History traversing commands such as `git-log` operate on a set
204of commits, not just a single commit. To these commands,
205specifying a single revision with the notation described in the
206previous section means the set of commits reachable from that
207commit, following the commit ancestry chain.
208
209To exclude commits reachable from a commit, a prefix `{caret}`
210notation is used. E.g. "`{caret}r1 r2`" means commits reachable
211from `r2` but exclude the ones reachable from `r1`.
212
213This set operation appears so often that there is a shorthand
214for it. "`r1..r2`" is equivalent to "`{caret}r1 r2`". It is
215the difference of two sets (subtract the set of commits
216reachable from `r1` from the set of commits reachable from
217`r2`).
218
219A similar notation "`r1\...r2`" is called symmetric difference
220of `r1` and `r2` and is defined as
221"`r1 r2 --not $(git-merge-base --all r1 r2)`".
222It it the set of commits that are reachable from either one of
223`r1` or `r2` but not from both.
224
225Here are a few examples:
226
227 D A B D
228 D F A B C D F
229 ^A G B D
230 ^A F B C F
231 G...I C D F G I
232 ^B G I C D F G I
233
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234Author
235------
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236Written by Linus Torvalds <torvalds@osdl.org> and
237Junio C Hamano <junkio@cox.net>
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238
239Documentation
240--------------
241Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>.
242
243GIT
244---
a7154e91 245Part of the gitlink:git[7] suite
7fc9d69f 246