Documentation: prepare to be consistent about "git-" versus "git "
[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 --always::
74 Show uniquely abbreviated commit object as fallback.
75
76 EXAMPLES
77 --------
78
79 With something like git.git current tree, I get:
80
81 [torvalds@g5 git]$ git-describe parent
82 v1.0.4-14-g2414721
83
84 i.e. the current head of my "parent" branch is based on v1.0.4,
85 but since it has a handful commits on top of that,
86 describe has added the number of additional commits ("14") and
87 an abbreviated object name for the commit itself ("2414721")
88 at the end.
89
90 The number of additional commits is the number
91 of commits which would be displayed by "git log v1.0.4..parent".
92 The hash suffix is "-g" + 7-char abbreviation for the tip commit
93 of parent (which was `2414721b194453f058079d897d13c4e377f92dc6`).
94
95 Doing a "git-describe" on a tag-name will just show the tag name:
96
97 [torvalds@g5 git]$ git-describe v1.0.4
98 v1.0.4
99
100 With --all, the command can use branch heads as references, so
101 the output shows the reference path as well:
102
103 [torvalds@g5 git]$ git describe --all --abbrev=4 v1.0.5^2
104 tags/v1.0.0-21-g975b
105
106 [torvalds@g5 git]$ git describe --all HEAD^
107 heads/lt/describe-7-g975b
108
109 With --abbrev set to 0, the command can be used to find the
110 closest tagname without any suffix:
111
112 [torvalds@g5 git]$ git describe --abbrev=0 v1.0.5^2
113 tags/v1.0.0
114
115 SEARCH STRATEGY
116 ---------------
117
118 For each committish supplied "git describe" will first look for
119 a tag which tags exactly that commit. Annotated tags will always
120 be preferred over lightweight tags, and tags with newer dates will
121 always be preferred over tags with older dates. If an exact match
122 is found, its name will be output and searching will stop.
123
124 If an exact match was not found "git describe" will walk back
125 through the commit history to locate an ancestor commit which
126 has been tagged. The ancestor's tag will be output along with an
127 abbreviation of the input committish's SHA1.
128
129 If multiple tags were found during the walk then the tag which
130 has the fewest commits different from the input committish will be
131 selected and output. Here fewest commits different is defined as
132 the number of commits which would be shown by "git log tag..input"
133 will be the smallest number of commits possible.
134
135
136 Author
137 ------
138 Written by Linus Torvalds <torvalds@osdl.org>, but somewhat
139 butchered by Junio C Hamano <junkio@cox.net>. Later significantly
140 updated by Shawn Pearce <spearce@spearce.org>.
141
142 Documentation
143 --------------
144 Documentation by David Greaves, Junio C Hamano and the git-list <git@vger.kernel.org>.
145
146 GIT
147 ---
148 Part of the linkgit:git[1] suite