help -a: do not unnecessarily look for a repository
[git/git.git] / Documentation / git-describe.txt
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1git-describe(1)
2===============
3
4NAME
5----
7bd7f280 6git-describe - Show the most recent tag that is reachable from a commit
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7
8
9SYNOPSIS
10--------
b1889c36 11'git describe' [--all] [--tags] [--contains] [--abbrev=<n>] <committish>...
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12
13DESCRIPTION
14-----------
15The command finds the most recent tag that is reachable from a
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16commit. If the tag points to the commit, then only the tag is
17shown. Otherwise, it suffixes the tag name with the number of
18additional commits on top of the tagged object and the
19abbreviated object name of the most recent commit.
c06818e2 20
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21By default (without --all or --tags) `git describe` only shows
22annotated tags. For more information about creating annotated tags
23see the -a and -s options to linkgit:git-tag[1].
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24
25OPTIONS
26-------
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27<committish>...::
28 Committish object names to describe.
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29
30--all::
31 Instead of using only the annotated tags, use any ref
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32 found in `.git/refs/`. This option enables matching
33 any known branch, remote branch, or lightweight tag.
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34
35--tags::
36 Instead of using only the annotated tags, use any tag
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37 found in `.git/refs/tags`. This option enables matching
38 a lightweight (non-annotated) tag.
c06818e2 39
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40--contains::
41 Instead of finding the tag that predates the commit, find
42 the tag that comes after the commit, and thus contains it.
43 Automatically implies --tags.
44
c06818e2 45--abbrev=<n>::
b938f62a 46 Instead of using the default 7 hexadecimal digits as the
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47 abbreviated object name, use <n> digits.
48
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49--candidates=<n>::
50 Instead of considering only the 10 most recent tags as
51 candidates to describe the input committish consider
52 up to <n> candidates. Increasing <n> above 10 will take
53 slightly longer but may produce a more accurate result.
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54 An <n> of 0 will cause only exact matches to be output.
55
56--exact-match::
57 Only output exact matches (a tag directly references the
58 supplied commit). This is a synonym for --candidates=0.
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59
60--debug::
61 Verbosely display information about the searching strategy
62 being employed to standard error. The tag name will still
63 be printed to standard out.
c06818e2 64
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65--long::
66 Always output the long format (the tag, the number of commits
67 and the abbreviated commit name) even when it matches a tag.
68 This is useful when you want to see parts of the commit object name
69 in "describe" output, even when the commit in question happens to be
70 a tagged version. Instead of just emitting the tag name, it will
71 describe such a commit as v1.2-0-deadbeef (0th commit since tag v1.2
72 that points at object deadbeef....).
73
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74--match <pattern>::
75 Only consider tags matching the given pattern (can be used to avoid
76 leaking private tags made from the repository).
77
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78--always::
79 Show uniquely abbreviated commit object as fallback.
80
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81EXAMPLES
82--------
83
84With something like git.git current tree, I get:
85
b1889c36 86 [torvalds@g5 git]$ git describe parent
1891261e 87 v1.0.4-14-g2414721
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88
89i.e. the current head of my "parent" branch is based on v1.0.4,
323b9db8 90but since it has a few commits on top of that,
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91describe has added the number of additional commits ("14") and
92an abbreviated object name for the commit itself ("2414721")
93at the end.
94
95The number of additional commits is the number
96of commits which would be displayed by "git log v1.0.4..parent".
97The hash suffix is "-g" + 7-char abbreviation for the tip commit
98of parent (which was `2414721b194453f058079d897d13c4e377f92dc6`).
c06818e2 99
ba020ef5 100Doing a 'git-describe' on a tag-name will just show the tag name:
c06818e2 101
b1889c36 102 [torvalds@g5 git]$ git describe v1.0.4
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103 v1.0.4
104
105With --all, the command can use branch heads as references, so
106the output shows the reference path as well:
107
108 [torvalds@g5 git]$ git describe --all --abbrev=4 v1.0.5^2
1891261e 109 tags/v1.0.0-21-g975b
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110
111 [torvalds@g5 git]$ git describe --all HEAD^
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112 heads/lt/describe-7-g975b
113
114With --abbrev set to 0, the command can be used to find the
115closest tagname without any suffix:
116
117 [torvalds@g5 git]$ git describe --abbrev=0 v1.0.5^2
118 tags/v1.0.0
c06818e2 119
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120SEARCH STRATEGY
121---------------
122
ba020ef5 123For each committish supplied, 'git-describe' will first look for
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124a tag which tags exactly that commit. Annotated tags will always
125be preferred over lightweight tags, and tags with newer dates will
126always be preferred over tags with older dates. If an exact match
127is found, its name will be output and searching will stop.
128
ba020ef5 129If an exact match was not found, 'git-describe' will walk back
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130through the commit history to locate an ancestor commit which
131has been tagged. The ancestor's tag will be output along with an
132abbreviation of the input committish's SHA1.
133
134If multiple tags were found during the walk then the tag which
135has the fewest commits different from the input committish will be
136selected and output. Here fewest commits different is defined as
483bc4f0 137the number of commits which would be shown by `git log tag..input`
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138will be the smallest number of commits possible.
139
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140
141Author
142------
143Written by Linus Torvalds <torvalds@osdl.org>, but somewhat
59eb68aa 144butchered by Junio C Hamano <gitster@pobox.com>. Later significantly
1891261e 145updated by Shawn Pearce <spearce@spearce.org>.
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146
147Documentation
148--------------
149Documentation by David Greaves, Junio C Hamano and the git-list <git@vger.kernel.org>.
150
151GIT
152---
9e1f0a85 153Part of the linkgit:git[1] suite