Documentation/git-describe.txt

   1 git-describe(1)
   2 ===============
   3
   4 NAME
   5 ----
   6 git-describe - Give an object a human readable name based on an available ref
   7
   8 SYNOPSIS
   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
  15 DESCRIPTION
  16 -----------
  17 The command finds the most recent tag that is reachable from a
  18 commit.  If the tag points to the commit, then only the tag is
  19 shown.  Otherwise, it suffixes the tag name with the number of
  20 additional commits on top of the tagged object and the
  21 abbreviated object name of the most recent commit. The result
  22 is a "human-readable" object name which can also be used to
  23 identify the commit to other git commands.
  24
  25 By default (without --all or --tags) `git describe` only shows
  26 annotated tags.  For more information about creating annotated tags
  27 see the -a and -s options to linkgit:git-tag[1].
  28
  29 If the given object refers to a blob, it will be described
  30 as `<commit-ish>:<path>`, such that the blob can be found
  31 at `<path>` in the `<commit-ish>`, which itself describes the
  32 first commit in which this blob occurs in a reverse revision walk
  33 from HEAD.
  34
  35 OPTIONS
  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
 126 EXAMPLES
 127 --------
 128
 129 With something like git.git current tree, I get:
 130
 131         [torvalds@g5 git]$ git describe parent
 132         v1.0.4-14-g2414721
 133
 134 i.e. the current head of my "parent" branch is based on v1.0.4,
 135 but since it has a few commits on top of that,
 136 describe has added the number of additional commits ("14") and
 137 an abbreviated object name for the commit itself ("2414721")
 138 at the end.
 139
 140 The number of additional commits is the number
 141 of commits which would be displayed by "git log v1.0.4..parent".
 142 The hash suffix is "-g" + 7-char abbreviation for the tip commit
 143 of parent (which was `2414721b194453f058079d897d13c4e377f92dc6`).
 144 The "g" prefix stands for "git" and is used to allow describing the version of
 145 a software depending on the SCM the software is managed with. This is useful
 146 in an environment where people may use different SCMs.
 147
 148 Doing 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
 153 With --all, the command can use branch heads as references, so
 154 the 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
 162 With --abbrev set to 0, the command can be used to find the
 163 closest tagname without any suffix:
 164
 165         [torvalds@g5 git]$ git describe --abbrev=0 v1.0.5^2
 166         tags/v1.0.0
 167
 168 Note that the suffix you get if you type these commands today may be
 169 longer than what Linus saw above when he ran these commands, as your
 170 Git repository may have new commits whose object names begin with
 171 975b that did not exist back then, and "-g975b" suffix alone may not
 172 be sufficient to disambiguate these commits.
 173
 174
 175 SEARCH STRATEGY
 176 ---------------
 177
 178 For each commit-ish supplied, 'git describe' will first look for
 179 a tag which tags exactly that commit.  Annotated tags will always
 180 be preferred over lightweight tags, and tags with newer dates will
 181 always be preferred over tags with older dates.  If an exact match
 182 is found, its name will be output and searching will stop.
 183
 184 If an exact match was not found, 'git describe' will walk back
 185 through the commit history to locate an ancestor commit which
 186 has been tagged.  The ancestor's tag will be output along with an
 187 abbreviation of the input commit-ish's SHA-1. If `--first-parent` was
 188 specified then the walk will only consider the first parent of each
 189 commit.
 190
 191 If multiple tags were found during the walk then the tag which
 192 has the fewest commits different from the input commit-ish will be
 193 selected and output.  Here fewest commits different is defined as
 194 the number of commits which would be shown by `git log tag..input`
 195 will be the smallest number of commits possible.
 196
 197 BUGS
 198 ----
 199
 200 Tree objects as well as tag objects not pointing at commits, cannot be described.
 201 When describing blobs, the lightweight tags pointing at blobs are ignored,
 202 but the blob is still described as <committ-ish>:<path> despite the lightweight
 203 tag being favorable.
 204
 205 GIT
 206 ---
 207 Part of the linkgit:git[1] suite