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 [verse]
  12 'git describe' [--all] [--tags] [--contains] [--abbrev=<n>] <committish>...
  13 'git describe' [--all] [--tags] [--contains] [--abbrev=<n>] --dirty[=<mark>]
  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.
  22
  23 By default (without --all or --tags) `git describe` only shows
  24 annotated tags.  For more information about creating annotated tags
  25 see the -a and -s options to linkgit:git-tag[1].
  26
  27 OPTIONS
  28 -------
  29 <committish>...::
  30         Committish object names to describe.
  31
  32 --dirty[=<mark>]::
  33         Describe the working tree.
  34         It means describe HEAD and appends <mark> (`-dirty` by
  35         default) if the working tree is dirty.
  36
  37 --all::
  38         Instead of using only the annotated tags, use any ref
  39         found in `.git/refs/`.  This option enables matching
  40         any known branch, remote branch, or lightweight tag.
  41
  42 --tags::
  43         Instead of using only the annotated tags, use any tag
  44         found in `.git/refs/tags`.  This option enables matching
  45         a lightweight (non-annotated) tag.
  46
  47 --contains::
  48         Instead of finding the tag that predates the commit, find
  49         the tag that comes after the commit, and thus contains it.
  50         Automatically implies --tags.
  51
  52 --abbrev=<n>::
  53         Instead of using the default 7 hexadecimal digits as the
  54         abbreviated object name, use <n> digits, or as many digits
  55         as needed to form a unique object name.  An <n> of 0
  56         will suppress long format, only showing the closest tag.
  57
  58 --candidates=<n>::
  59         Instead of considering only the 10 most recent tags as
  60         candidates to describe the input committish consider
  61         up to <n> candidates.  Increasing <n> above 10 will take
  62         slightly longer but may produce a more accurate result.
  63         An <n> of 0 will cause only exact matches to be output.
  64
  65 --exact-match::
  66         Only output exact matches (a tag directly references the
  67         supplied commit).  This is a synonym for --candidates=0.
  68
  69 --debug::
  70         Verbosely display information about the searching strategy
  71         being employed to standard error.  The tag name will still
  72         be printed to standard out.
  73
  74 --long::
  75         Always output the long format (the tag, the number of commits
  76         and the abbreviated commit name) even when it matches a tag.
  77         This is useful when you want to see parts of the commit object name
  78         in "describe" output, even when the commit in question happens to be
  79         a tagged version.  Instead of just emitting the tag name, it will
  80         describe such a commit as v1.2-0-gdeadbee (0th commit since tag v1.2
  81         that points at object deadbee....).
  82
  83 --match <pattern>::
  84         Only consider tags matching the given pattern (can be used to avoid
  85         leaking private tags made from the repository).
  86
  87 --always::
  88         Show uniquely abbreviated commit object as fallback.
  89
  90 EXAMPLES
  91 --------
  92
  93 With something like git.git current tree, I get:
  94
  95         [torvalds@g5 git]$ git describe parent
  96         v1.0.4-14-g2414721
  97
  98 i.e. the current head of my "parent" branch is based on v1.0.4,
  99 but since it has a few commits on top of that,
 100 describe has added the number of additional commits ("14") and
 101 an abbreviated object name for the commit itself ("2414721")
 102 at the end.
 103
 104 The number of additional commits is the number
 105 of commits which would be displayed by "git log v1.0.4..parent".
 106 The hash suffix is "-g" + 7-char abbreviation for the tip commit
 107 of parent (which was `2414721b194453f058079d897d13c4e377f92dc6`).
 108
 109 Doing a 'git describe' on a tag-name will just show the tag name:
 110
 111         [torvalds@g5 git]$ git describe v1.0.4
 112         v1.0.4
 113
 114 With --all, the command can use branch heads as references, so
 115 the output shows the reference path as well:
 116
 117         [torvalds@g5 git]$ git describe --all --abbrev=4 v1.0.5^2
 118         tags/v1.0.0-21-g975b
 119
 120         [torvalds@g5 git]$ git describe --all --abbrev=4 HEAD^
 121         heads/lt/describe-7-g975b
 122
 123 With --abbrev set to 0, the command can be used to find the
 124 closest tagname without any suffix:
 125
 126         [torvalds@g5 git]$ git describe --abbrev=0 v1.0.5^2
 127         tags/v1.0.0
 128
 129 Note that the suffix you get if you type these commands today may be
 130 longer than what Linus saw above when he ran these commands, as your
 131 git repository may have new commits whose object names begin with
 132 975b that did not exist back then, and "-g975b" suffix alone may not
 133 be sufficient to disambiguate these commits.
 134
 135
 136 SEARCH STRATEGY
 137 ---------------
 138
 139 For each committish supplied, 'git describe' will first look for
 140 a tag which tags exactly that commit.  Annotated tags will always
 141 be preferred over lightweight tags, and tags with newer dates will
 142 always be preferred over tags with older dates.  If an exact match
 143 is found, its name will be output and searching will stop.
 144
 145 If an exact match was not found, 'git describe' will walk back
 146 through the commit history to locate an ancestor commit which
 147 has been tagged.  The ancestor's tag will be output along with an
 148 abbreviation of the input committish's SHA1.
 149
 150 If multiple tags were found during the walk then the tag which
 151 has the fewest commits different from the input committish will be
 152 selected and output.  Here fewest commits different is defined as
 153 the number of commits which would be shown by `git log tag..input`
 154 will be the smallest number of commits possible.
 155
 156
 157 Author
 158 ------
 159 Written by Linus Torvalds <torvalds@osdl.org>, but somewhat
 160 butchered by Junio C Hamano <gitster@pobox.com>.  Later significantly
 161 updated by Shawn Pearce <spearce@spearce.org>.
 162
 163 Documentation
 164 --------------
 165 Documentation by David Greaves, Junio C Hamano and the git-list <git@vger.kernel.org>.
 166
 167 GIT
 168 ---
 169 Part of the linkgit:git[1] suite