Merge branch 'maint-1.5.4' into maint
[git/git.git] / Documentation / git-describe.txt
1 git-describe(1)
2 ===============
3
4 NAME
5 ----
6 git-describe - Show the most recent tag that is reachable from a commit
7
8
9 SYNOPSIS
10 --------
11 'git-describe' [--all] [--tags] [--contains] [--abbrev=<n>] <committish>...
12
13 DESCRIPTION
14 -----------
15 The command finds the most recent tag that is reachable from a
16 commit. If the tag points to the commit, then only the tag is
17 shown. Otherwise, it suffixes the tag name with the number of
18 additional commits on top of the tagged object and the
19 abbreviated object name of the most recent commit.
20
21
22 OPTIONS
23 -------
24 <committish>::
25 The object name of the committish.
26
27 --all::
28 Instead of using only the annotated tags, use any ref
29 found in `.git/refs/`.
30
31 --tags::
32 Instead of using only the annotated tags, use any tag
33 found in `.git/refs/tags`.
34
35 --contains::
36 Instead of finding the tag that predates the commit, find
37 the tag that comes after the commit, and thus contains it.
38 Automatically implies --tags.
39
40 --abbrev=<n>::
41 Instead of using the default 8 hexadecimal digits as the
42 abbreviated object name, use <n> digits.
43
44 --candidates=<n>::
45 Instead of considering only the 10 most recent tags as
46 candidates to describe the input committish consider
47 up to <n> candidates. Increasing <n> above 10 will take
48 slightly longer but may produce a more accurate result.
49 An <n> of 0 will cause only exact matches to be output.
50
51 --exact-match::
52 Only output exact matches (a tag directly references the
53 supplied commit). This is a synonym for --candidates=0.
54
55 --debug::
56 Verbosely display information about the searching strategy
57 being employed to standard error. The tag name will still
58 be printed to standard out.
59
60 --long::
61 Always output the long format (the tag, the number of commits
62 and the abbreviated commit name) even when it matches a tag.
63 This is useful when you want to see parts of the commit object name
64 in "describe" output, even when the commit in question happens to be
65 a tagged version. Instead of just emitting the tag name, it will
66 describe such a commit as v1.2-0-deadbeef (0th commit since tag v1.2
67 that points at object deadbeef....).
68
69 --match <pattern>::
70 Only consider tags matching the given pattern (can be used to avoid
71 leaking private tags made from the repository).
72
73 EXAMPLES
74 --------
75
76 With something like git.git current tree, I get:
77
78 [torvalds@g5 git]$ git-describe parent
79 v1.0.4-14-g2414721
80
81 i.e. the current head of my "parent" branch is based on v1.0.4,
82 but since it has a handful commits on top of that,
83 describe has added the number of additional commits ("14") and
84 an abbreviated object name for the commit itself ("2414721")
85 at the end.
86
87 The number of additional commits is the number
88 of commits which would be displayed by "git log v1.0.4..parent".
89 The hash suffix is "-g" + 7-char abbreviation for the tip commit
90 of parent (which was `2414721b194453f058079d897d13c4e377f92dc6`).
91
92 Doing a "git-describe" on a tag-name will just show the tag name:
93
94 [torvalds@g5 git]$ git-describe v1.0.4
95 v1.0.4
96
97 With --all, the command can use branch heads as references, so
98 the output shows the reference path as well:
99
100 [torvalds@g5 git]$ git describe --all --abbrev=4 v1.0.5^2
101 tags/v1.0.0-21-g975b
102
103 [torvalds@g5 git]$ git describe --all HEAD^
104 heads/lt/describe-7-g975b
105
106 With --abbrev set to 0, the command can be used to find the
107 closest tagname without any suffix:
108
109 [torvalds@g5 git]$ git describe --abbrev=0 v1.0.5^2
110 tags/v1.0.0
111
112 SEARCH STRATEGY
113 ---------------
114
115 For each committish supplied "git describe" will first look for
116 a tag which tags exactly that commit. Annotated tags will always
117 be preferred over lightweight tags, and tags with newer dates will
118 always be preferred over tags with older dates. If an exact match
119 is found, its name will be output and searching will stop.
120
121 If an exact match was not found "git describe" will walk back
122 through the commit history to locate an ancestor commit which
123 has been tagged. The ancestor's tag will be output along with an
124 abbreviation of the input committish's SHA1.
125
126 If multiple tags were found during the walk then the tag which
127 has the fewest commits different from the input committish will be
128 selected and output. Here fewest commits different is defined as
129 the number of commits which would be shown by "git log tag..input"
130 will be the smallest number of commits possible.
131
132
133 Author
134 ------
135 Written by Linus Torvalds <torvalds@osdl.org>, but somewhat
136 butchered by Junio C Hamano <junkio@cox.net>. Later significantly
137 updated by Shawn Pearce <spearce@spearce.org>.
138
139 Documentation
140 --------------
141 Documentation by David Greaves, Junio C Hamano and the git-list <git@vger.kernel.org>.
142
143 GIT
144 ---
145 Part of the linkgit:git[7] suite