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 `refs/` namespace.  This option enables matching
  40         any known branch, remote-tracking branch, or lightweight tag.
  41
  42 --tags::
  43         Instead of using only the annotated tags, use any tag
  44         found in `refs/tags` namespace.  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 `glob(7)` pattern,
  85         excluding the "refs/tags/" prefix.  This can be used to avoid
  86         leaking private tags from the repository.
  87
  88 --always::
  89         Show uniquely abbreviated commit object as fallback.
  90
  91 EXAMPLES
  92 --------
  93
  94 With something like git.git current tree, I get:
  95
  96         [torvalds@g5 git]$ git describe parent
  97         v1.0.4-14-g2414721
  98
  99 i.e. the current head of my "parent" branch is based on v1.0.4,
 100 but since it has a few commits on top of that,
 101 describe has added the number of additional commits ("14") and
 102 an abbreviated object name for the commit itself ("2414721")
 103 at the end.
 104
 105 The number of additional commits is the number
 106 of commits which would be displayed by "git log v1.0.4..parent".
 107 The hash suffix is "-g" + 7-char abbreviation for the tip commit
 108 of parent (which was `2414721b194453f058079d897d13c4e377f92dc6`).
 109 The "g" prefix stands for "git" and is used to allow describing the version of
 110 a software depending on the SCM the software is managed with. This is useful
 111 in an environment where people may use different SCMs.
 112
 113 Doing a 'git describe' on a tag-name will just show the tag name:
 114
 115         [torvalds@g5 git]$ git describe v1.0.4
 116         v1.0.4
 117
 118 With --all, the command can use branch heads as references, so
 119 the output shows the reference path as well:
 120
 121         [torvalds@g5 git]$ git describe --all --abbrev=4 v1.0.5^2
 122         tags/v1.0.0-21-g975b
 123
 124         [torvalds@g5 git]$ git describe --all --abbrev=4 HEAD^
 125         heads/lt/describe-7-g975b
 126
 127 With --abbrev set to 0, the command can be used to find the
 128 closest tagname without any suffix:
 129
 130         [torvalds@g5 git]$ git describe --abbrev=0 v1.0.5^2
 131         tags/v1.0.0
 132
 133 Note that the suffix you get if you type these commands today may be
 134 longer than what Linus saw above when he ran these commands, as your
 135 Git repository may have new commits whose object names begin with
 136 975b that did not exist back then, and "-g975b" suffix alone may not
 137 be sufficient to disambiguate these commits.
 138
 139
 140 SEARCH STRATEGY
 141 ---------------
 142
 143 For each committish supplied, 'git describe' will first look for
 144 a tag which tags exactly that commit.  Annotated tags will always
 145 be preferred over lightweight tags, and tags with newer dates will
 146 always be preferred over tags with older dates.  If an exact match
 147 is found, its name will be output and searching will stop.
 148
 149 If an exact match was not found, 'git describe' will walk back
 150 through the commit history to locate an ancestor commit which
 151 has been tagged.  The ancestor's tag will be output along with an
 152 abbreviation of the input committish's SHA-1.
 153
 154 If multiple tags were found during the walk then the tag which
 155 has the fewest commits different from the input committish will be
 156 selected and output.  Here fewest commits different is defined as
 157 the number of commits which would be shown by `git log tag..input`
 158 will be the smallest number of commits possible.
 159
 160 GIT
 161 ---
 162 Part of the linkgit:git[1] suite