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1git-describe(1)
2===============
3
4NAME
5----
6git-describe - Give an object a human readable name based on an available ref
7
8SYNOPSIS
9--------
10[verse]
11'git describe' [--all] [--tags] [--contains] [--abbrev=<n>] [<commit-ish>...]
12'git describe' [--all] [--tags] [--contains] [--abbrev=<n>] --dirty[=<mark>]
13'git describe' <blob>
14
15DESCRIPTION
16-----------
17The command finds the most recent tag that is reachable from a
18commit. If the tag points to the commit, then only the tag is
19shown. Otherwise, it suffixes the tag name with the number of
20additional commits on top of the tagged object and the
21abbreviated object name of the most recent commit. The result
22is a "human-readable" object name which can also be used to
23identify the commit to other git commands.
24
25By default (without --all or --tags) `git describe` only shows
26annotated tags. For more information about creating annotated tags
27see the -a and -s options to linkgit:git-tag[1].
28
29If the given object refers to a blob, it will be described
30as `<commit-ish>:<path>`, such that the blob can be found
31at `<path>` in the `<commit-ish>`, which itself describes the
32first commit in which this blob occurs in a reverse revision walk
33from HEAD.
34
35OPTIONS
36-------
37<commit-ish>...::
38 Commit-ish object names to describe. Defaults to HEAD if omitted.
39
40--dirty[=<mark>]::
41--broken[=<mark>]::
42 Describe the state of the working tree. When the working
43 tree matches HEAD, the output is the same as "git describe
44 HEAD". If the working tree has local modification "-dirty"
45 is appended to it. If a repository is corrupt and Git
46 cannot determine if there is local modification, Git will
47 error out, unless `--broken' is given, which appends
48 the suffix "-broken" instead.
49
50--all::
51 Instead of using only the annotated tags, use any ref
52 found in `refs/` namespace. This option enables matching
53 any known branch, remote-tracking branch, or lightweight tag.
54
55--tags::
56 Instead of using only the annotated tags, use any tag
57 found in `refs/tags` namespace. This option enables matching
58 a lightweight (non-annotated) tag.
59
60--contains::
61 Instead of finding the tag that predates the commit, find
62 the tag that comes after the commit, and thus contains it.
63 Automatically implies --tags.
64
65--abbrev=<n>::
66 Instead of using the default 7 hexadecimal digits as the
67 abbreviated object name, use <n> digits, or as many digits
68 as needed to form a unique object name. An <n> of 0
69 will suppress long format, only showing the closest tag.
70
71--candidates=<n>::
72 Instead of considering only the 10 most recent tags as
73 candidates to describe the input commit-ish consider
74 up to <n> candidates. Increasing <n> above 10 will take
75 slightly longer but may produce a more accurate result.
76 An <n> of 0 will cause only exact matches to be output.
77
78--exact-match::
79 Only output exact matches (a tag directly references the
80 supplied commit). This is a synonym for --candidates=0.
81
82--debug::
83 Verbosely display information about the searching strategy
84 being employed to standard error. The tag name will still
85 be printed to standard out.
86
87--long::
88 Always output the long format (the tag, the number of commits
89 and the abbreviated commit name) even when it matches a tag.
90 This is useful when you want to see parts of the commit object name
91 in "describe" output, even when the commit in question happens to be
92 a tagged version. Instead of just emitting the tag name, it will
93 describe such a commit as v1.2-0-gdeadbee (0th commit since tag v1.2
94 that points at object deadbee....).
95
96--match <pattern>::
97 Only consider tags matching the given `glob(7)` pattern,
98 excluding the "refs/tags/" prefix. If used with `--all`, it also
99 considers local branches and remote-tracking references matching the
100 pattern, excluding respectively "refs/heads/" and "refs/remotes/"
101 prefix; references of other types are never considered. If given
102 multiple times, a list of patterns will be accumulated, and tags
103 matching any of the patterns will be considered. Use `--no-match` to
104 clear and reset the list of patterns.
105
106--exclude <pattern>::
107 Do not consider tags matching the given `glob(7)` pattern, excluding
108 the "refs/tags/" prefix. If used with `--all`, it also does not consider
109 local branches and remote-tracking references matching the pattern,
110 excluding respectively "refs/heads/" and "refs/remotes/" prefix;
111 references of other types are never considered. If given multiple times,
112 a list of patterns will be accumulated and tags matching any of the
113 patterns will be excluded. When combined with --match a tag will be
114 considered when it matches at least one --match pattern and does not
115 match any of the --exclude patterns. Use `--no-exclude` to clear and
116 reset the list of patterns.
117
118--always::
119 Show uniquely abbreviated commit object as fallback.
120
121--first-parent::
122 Follow only the first parent commit upon seeing a merge commit.
123 This is useful when you wish to not match tags on branches merged
124 in the history of the target commit.
125
126EXAMPLES
127--------
128
129With something like git.git current tree, I get:
130
131 [torvalds@g5 git]$ git describe parent
132 v1.0.4-14-g2414721
133
134i.e. the current head of my "parent" branch is based on v1.0.4,
135but since it has a few commits on top of that,
136describe has added the number of additional commits ("14") and
137an abbreviated object name for the commit itself ("2414721")
138at the end.
139
140The number of additional commits is the number
141of commits which would be displayed by "git log v1.0.4..parent".
142The hash suffix is "-g" + unambiguous abbreviation for the tip commit
143of parent (which was `2414721b194453f058079d897d13c4e377f92dc6`).
144The "g" prefix stands for "git" and is used to allow describing the version of
145a software depending on the SCM the software is managed with. This is useful
146in an environment where people may use different SCMs.
147
148Doing a 'git describe' on a tag-name will just show the tag name:
149
150 [torvalds@g5 git]$ git describe v1.0.4
151 v1.0.4
152
153With --all, the command can use branch heads as references, so
154the output shows the reference path as well:
155
156 [torvalds@g5 git]$ git describe --all --abbrev=4 v1.0.5^2
157 tags/v1.0.0-21-g975b
158
159 [torvalds@g5 git]$ git describe --all --abbrev=4 HEAD^
160 heads/lt/describe-7-g975b
161
162With --abbrev set to 0, the command can be used to find the
163closest tagname without any suffix:
164
165 [torvalds@g5 git]$ git describe --abbrev=0 v1.0.5^2
166 tags/v1.0.0
167
168Note that the suffix you get if you type these commands today may be
169longer than what Linus saw above when he ran these commands, as your
170Git repository may have new commits whose object names begin with
171975b that did not exist back then, and "-g975b" suffix alone may not
172be sufficient to disambiguate these commits.
173
174
175SEARCH STRATEGY
176---------------
177
178For each commit-ish supplied, 'git describe' will first look for
179a tag which tags exactly that commit. Annotated tags will always
180be preferred over lightweight tags, and tags with newer dates will
181always be preferred over tags with older dates. If an exact match
182is found, its name will be output and searching will stop.
183
184If an exact match was not found, 'git describe' will walk back
185through the commit history to locate an ancestor commit which
186has been tagged. The ancestor's tag will be output along with an
187abbreviation of the input commit-ish's SHA-1. If `--first-parent` was
188specified then the walk will only consider the first parent of each
189commit.
190
191If multiple tags were found during the walk then the tag which
192has the fewest commits different from the input commit-ish will be
193selected and output. Here fewest commits different is defined as
194the number of commits which would be shown by `git log tag..input`
195will be the smallest number of commits possible.
196
197BUGS
198----
199
200Tree objects as well as tag objects not pointing at commits, cannot be described.
201When describing blobs, the lightweight tags pointing at blobs are ignored,
202but the blob is still described as <committ-ish>:<path> despite the lightweight
203tag being favorable.
204
205GIT
206---
207Part of the linkgit:git[1] suite