Merge fixes up to GIT 1.2.2
[git/git.git] / Documentation / git-rev-parse.txt
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1git-rev-parse(1)
2================
3
4NAME
5----
5077fa9c 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-----------
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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.
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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 `$GIT_DIR/refs`.
69
70--show-prefix::
5f94c730 71 When the command is invoked from a subdirectory, show the
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72 path of the current directory relative to the top-level
73 directory.
7fc9d69f 74
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75--show-cdup::
76 When the command is invoked from a subdirectory, show the
77 path of the top-level directory relative to the current
78 directory (typically a sequence of "../", or an empty string).
79
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80--git-dir::
81 Show `$GIT_DIR` if defined else show the path to the .git directory.
82
83--short, short=number::
84 Instead of outputting the full SHA1 values of object names try to
85 abbriviate them to a shorter unique name. When no length is specified
86 7 is used. The minimum length is 4.
87
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88--since=datestring, --after=datestring::
89 Parses the date string, and outputs corresponding
90 --max-age= parameter for git-rev-list command.
91
92--until=datestring, --before=datestring::
93 Parses the date string, and outputs corresponding
94 --min-age= parameter for git-rev-list command.
95
7fc9d69f 96<args>...::
5077fa9c 97 Flags and parameters to be parsed.
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98
99
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100SPECIFYING REVISIONS
101--------------------
102
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103A revision parameter typically, but not necessarily, names a
104commit object. They use what is called an 'extended SHA1'
105syntax.
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106
107* The full SHA1 object name (40-byte hexadecimal string), or
108 a substring of such that is unique within the repository.
109 E.g. dae86e1950b1277e545cee180551750029cfe735 and dae86e both
110 name the same commit object if there are no other object in
111 your repository whose object name starts with dae86e.
112
113* A symbolic ref name. E.g. 'master' typically means the commit
114 object referenced by $GIT_DIR/refs/heads/master. If you
115 happen to have both heads/master and tags/master, you can
72e9340c 116 explicitly say 'heads/master' to tell git which one you mean.
3a45f625 117
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118* A suffix '{caret}' to a revision parameter means the first parent of
119 that commit object. '{caret}<n>' means the <n>th parent (i.e.
120 'rev{caret}'
121 is equivalent to 'rev{caret}1'). As a special rule,
122 'rev{caret}0' means the commit itself and is used when 'rev' is the
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123 object name of a tag object that refers to a commit object.
124
125* A suffix '~<n>' to a revision parameter means the commit
126 object that is the <n>th generation grand-parent of the named
127 commit object, following only the first parent. I.e. rev~3 is
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128 equivalent to rev{caret}{caret}{caret} which is equivalent to\
129 rev{caret}1{caret}1{caret}1.
3a45f625 130
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131* A suffix '{caret}' followed by an object type name enclosed in
132 brace pair (e.g. `v0.99.8{caret}\{commit\}`) means the object
133 could be a tag, and dereference the tag recursively until an
134 object of that type is found or the object cannot be
135 dereferenced anymore (in which case, barf). `rev{caret}0`
136 introduced earlier is a short-hand for `rev{caret}\{commit\}`.
137
138* A suffix '{caret}' followed by an empty brace pair
139 (e.g. `v0.99.8{caret}\{\}`) means the object could be a tag,
140 and dereference the tag recursively until a non-tag object is
141 found.
142
babfaba2 143'git-rev-parse' also accepts a prefix '{caret}' to revision parameter,
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144which is passed to 'git-rev-list'. Two revision parameters
145concatenated with '..' is a short-hand for writing a range
babfaba2 146between them. I.e. 'r1..r2' is equivalent to saying '{caret}r1 r2'
3a45f625 147
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148Here is an illustration, by Jon Loeliger. Both node B and C are
149a commit parents of commit node A. Parent commits are ordered
150left-to-right.
151
152 G H I J
153 \ / \ /
154 D E F
155 \ | /
156 \ | /
157 \|/
158 B C
159 \ /
160 \ /
161 A
162
163 A = = A^0
164 B = A^ = A^1 = A~1
165 C = A^2 = A^2
166 D = A^^ = A^1^1 = A~2
167 E = B^2 = A^^2
168 F = B^3 = A^^3
169 G = A^^^ = A^1^1^1 = A~3
170 H = D^2 = B^^2 = A^^^2 = A~2^2
171 I = F^ = B^3^ = A^^3^
172 J = F^2 = B^3^2 = A^^3^2
173
3a45f625 174
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175Author
176------
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177Written by Linus Torvalds <torvalds@osdl.org> and
178Junio C Hamano <junkio@cox.net>
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179
180Documentation
181--------------
182Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>.
183
184GIT
185---
a7154e91 186Part of the gitlink:git[7] suite
7fc9d69f 187