Merge branch 'ks/maint-mailinfo-folded'
[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 By default (without --all or --tags) `git describe` only shows
22 annotated tags. For more information about creating annotated tags
23 see the -a and -s options to linkgit:git-tag[1].
24
25 OPTIONS
26 -------
27 <committish>...::
28 Committish object names to describe.
29
30 --all::
31 Instead of using only the annotated tags, use any ref
32 found in `.git/refs/`. This option enables matching
33 any known branch, remote branch, or lightweight tag.
34
35 --tags::
36 Instead of using only the annotated tags, use any tag
37 found in `.git/refs/tags`. This option enables matching
38 a lightweight (non-annotated) tag.
39
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
45 --abbrev=<n>::
46 Instead of using the default 7 hexadecimal digits as the
47 abbreviated object name, use <n> digits.
48
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.
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.
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.
64
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
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
78 --always::
79 Show uniquely abbreviated commit object as fallback.
80
81 EXAMPLES
82 --------
83
84 With something like git.git current tree, I get:
85
86 [torvalds@g5 git]$ git describe parent
87 v1.0.4-14-g2414721
88
89 i.e. the current head of my "parent" branch is based on v1.0.4,
90 but since it has a few commits on top of that,
91 describe has added the number of additional commits ("14") and
92 an abbreviated object name for the commit itself ("2414721")
93 at the end.
94
95 The number of additional commits is the number
96 of commits which would be displayed by "git log v1.0.4..parent".
97 The hash suffix is "-g" + 7-char abbreviation for the tip commit
98 of parent (which was `2414721b194453f058079d897d13c4e377f92dc6`).
99
100 Doing a 'git-describe' on a tag-name will just show the tag name:
101
102 [torvalds@g5 git]$ git describe v1.0.4
103 v1.0.4
104
105 With --all, the command can use branch heads as references, so
106 the output shows the reference path as well:
107
108 [torvalds@g5 git]$ git describe --all --abbrev=4 v1.0.5^2
109 tags/v1.0.0-21-g975b
110
111 [torvalds@g5 git]$ git describe --all HEAD^
112 heads/lt/describe-7-g975b
113
114 With --abbrev set to 0, the command can be used to find the
115 closest tagname without any suffix:
116
117 [torvalds@g5 git]$ git describe --abbrev=0 v1.0.5^2
118 tags/v1.0.0
119
120 SEARCH STRATEGY
121 ---------------
122
123 For each committish supplied, 'git-describe' will first look for
124 a tag which tags exactly that commit. Annotated tags will always
125 be preferred over lightweight tags, and tags with newer dates will
126 always be preferred over tags with older dates. If an exact match
127 is found, its name will be output and searching will stop.
128
129 If an exact match was not found, 'git-describe' will walk back
130 through the commit history to locate an ancestor commit which
131 has been tagged. The ancestor's tag will be output along with an
132 abbreviation of the input committish's SHA1.
133
134 If multiple tags were found during the walk then the tag which
135 has the fewest commits different from the input committish will be
136 selected and output. Here fewest commits different is defined as
137 the number of commits which would be shown by `git log tag..input`
138 will be the smallest number of commits possible.
139
140
141 Author
142 ------
143 Written by Linus Torvalds <torvalds@osdl.org>, but somewhat
144 butchered by Junio C Hamano <gitster@pobox.com>. Later significantly
145 updated by Shawn Pearce <spearce@spearce.org>.
146
147 Documentation
148 --------------
149 Documentation by David Greaves, Junio C Hamano and the git-list <git@vger.kernel.org>.
150
151 GIT
152 ---
153 Part of the linkgit:git[1] suite