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[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--------
11'git-describe' [--all] [--tags] [--abbrev=<n>] <committish>...
12
13DESCRIPTION
14-----------
15The command finds the most recent tag that is reachable from a
16commit, and if the commit itself is pointed at by the tag, shows
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17the tag. Otherwise, it suffixes the tag name with the number of
18additional commits and the abbreviated object name of the commit.
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19
20
21OPTIONS
22-------
23<committish>::
37425065 24 The object name of the committish.
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25
26--all::
27 Instead of using only the annotated tags, use any ref
28 found in `.git/refs/`.
29
30--tags::
31 Instead of using only the annotated tags, use any tag
32 found in `.git/refs/tags`.
33
34--abbrev=<n>::
35 Instead of using the default 8 hexadecimal digits as the
36 abbreviated object name, use <n> digits.
37
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38--candidates=<n>::
39 Instead of considering only the 10 most recent tags as
40 candidates to describe the input committish consider
41 up to <n> candidates. Increasing <n> above 10 will take
42 slightly longer but may produce a more accurate result.
43
44--debug::
45 Verbosely display information about the searching strategy
46 being employed to standard error. The tag name will still
47 be printed to standard out.
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48
49EXAMPLES
50--------
51
52With something like git.git current tree, I get:
53
54 [torvalds@g5 git]$ git-describe parent
1891261e 55 v1.0.4-14-g2414721
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56
57i.e. the current head of my "parent" branch is based on v1.0.4,
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58but since it has a handful commits on top of that,
59describe has added the number of additional commits ("14") and
60an abbreviated object name for the commit itself ("2414721")
61at the end.
62
63The number of additional commits is the number
64of commits which would be displayed by "git log v1.0.4..parent".
65The hash suffix is "-g" + 7-char abbreviation for the tip commit
66of parent (which was `2414721b194453f058079d897d13c4e377f92dc6`).
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67
68Doing a "git-describe" on a tag-name will just show the tag name:
69
70 [torvalds@g5 git]$ git-describe v1.0.4
71 v1.0.4
72
73With --all, the command can use branch heads as references, so
74the output shows the reference path as well:
75
76 [torvalds@g5 git]$ git describe --all --abbrev=4 v1.0.5^2
1891261e 77 tags/v1.0.0-21-g975b
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78
79 [torvalds@g5 git]$ git describe --all HEAD^
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80 heads/lt/describe-7-g975b
81
82With --abbrev set to 0, the command can be used to find the
83closest tagname without any suffix:
84
85 [torvalds@g5 git]$ git describe --abbrev=0 v1.0.5^2
86 tags/v1.0.0
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88SEARCH STRATEGY
89---------------
90
91For each committish supplied "git describe" will first look for
92a tag which tags exactly that commit. Annotated tags will always
93be preferred over lightweight tags, and tags with newer dates will
94always be preferred over tags with older dates. If an exact match
95is found, its name will be output and searching will stop.
96
97If an exact match was not found "git describe" will walk back
98through the commit history to locate an ancestor commit which
99has been tagged. The ancestor's tag will be output along with an
100abbreviation of the input committish's SHA1.
101
102If multiple tags were found during the walk then the tag which
103has the fewest commits different from the input committish will be
104selected and output. Here fewest commits different is defined as
105the number of commits which would be shown by "git log tag..input"
106will be the smallest number of commits possible.
107
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108
109Author
110------
111Written by Linus Torvalds <torvalds@osdl.org>, but somewhat
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112butchered by Junio C Hamano <junkio@cox.net>. Later significantly
113updated by Shawn Pearce <spearce@spearce.org>.
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114
115Documentation
116--------------
117Documentation by David Greaves, Junio C Hamano and the git-list <git@vger.kernel.org>.
118
119GIT
120---
121Part of the gitlink:git[7] suite
122