Documentation / git-rev-parse.txton commit Merge branch 'js/portable' into next (21a0233)
   1git-rev-parse(1)
   2================
   3
   4NAME
   5----
   6git-rev-parse - Pick out and massage parameters.
   7
   8
   9SYNOPSIS
  10--------
  11'git-rev-parse' [ --option ] <args>...
  12
  13DESCRIPTION
  14-----------
  15
  16Many git Porcelainish commands take mixture of flags
  17(i.e. parameters that begin with a dash '-') and parameters
  18meant for underlying `git-rev-list` command they use internally
  19and flags and parameters for other commands they use as the
  20downstream of `git-rev-list`.  This command is used to
  21distinguish between them.
  22
  23
  24OPTIONS
  25-------
  26--revs-only::
  27        Do not output flags and parameters not meant for
  28        `git-rev-list` command.
  29
  30--no-revs::
  31        Do not output flags and parameters meant for
  32        `git-rev-list` command.
  33
  34--flags::
  35        Do not output non-flag parameters.
  36
  37--no-flags::
  38        Do not output flag parameters.
  39
  40--default <arg>::
  41        If there is no parameter given by the user, use `<arg>`
  42        instead.
  43
  44--verify::
  45        The parameter given must be usable as a single, valid
  46        object name.  Otherwise barf and abort.
  47
  48--sq::
  49        Usually the output is made one line per flag and
  50        parameter.  This option makes output a single line,
  51        properly quoted for consumption by shell.  Useful when
  52        you expect your parameter to contain whitespaces and
  53        newlines (e.g. when using pickaxe `-S` with
  54        `git-diff-\*`).
  55
  56--not::
  57        When showing object names, prefix them with '{caret}' and
  58        strip '{caret}' prefix from the object names that already have
  59        one.
  60
  61--symbolic::
  62        Usually the object names are output in SHA1 form (with
  63        possible '{caret}' prefix); this option makes them output in a
  64        form as close to the original input as possible.
  65
  66
  67--all::
  68        Show all refs found in `$GIT_DIR/refs`.
  69
  70--show-prefix::
  71        When the command is invoked from a subdirectory, show the
  72        path of the current directory relative to the top-level
  73        directory.
  74
  75--show-cdup::
  76        When the command is invoked from a subdirectory, show the
  77        path of the top-level directory relative to the current
  78        directory (typically a sequence of "../", or an empty string).
  79
  80--git-dir::
  81        Show `$GIT_DIR` if defined else show the path to the .git directory.
  82
  83--short, short=number::
  84        Instead of outputting the full SHA1 values of object names try to
  85        abbriviate them to a shorter unique name. When no length is specified
  86        7 is used. The minimum length is 4.
  87
  88--since=datestring, --after=datestring::
  89        Parses the date string, and outputs corresponding
  90        --max-age= parameter for git-rev-list command.
  91
  92--until=datestring, --before=datestring::
  93        Parses the date string, and outputs corresponding
  94        --min-age= parameter for git-rev-list command.
  95
  96<args>...::
  97        Flags and parameters to be parsed.
  98
  99
 100SPECIFYING REVISIONS
 101--------------------
 102
 103A revision parameter typically, but not necessarily, names a
 104commit object.  They use what is called an 'extended SHA1'
 105syntax.
 106
 107* The full SHA1 object name (40-byte hexadecimal string), or
 108  a substring of such that is unique within the repository.
 109  E.g. dae86e1950b1277e545cee180551750029cfe735 and dae86e both
 110  name the same commit object if there are no other object in
 111  your repository whose object name starts with dae86e.
 112
 113* A symbolic ref name.  E.g. 'master' typically means the commit
 114  object referenced by $GIT_DIR/refs/heads/master.  If you
 115  happen to have both heads/master and tags/master, you can
 116  explicitly say 'heads/master' to tell git which one you mean.
 117
 118* A suffix '{caret}' to a revision parameter means the first parent of
 119  that commit object.  '{caret}<n>' means the <n>th parent (i.e.
 120  'rev{caret}'
 121  is equivalent to 'rev{caret}1').  As a special rule,
 122  'rev{caret}0' means the commit itself and is used when 'rev' is the
 123  object name of a tag object that refers to a commit object.
 124
 125* A suffix '~<n>' to a revision parameter means the commit
 126  object that is the <n>th generation grand-parent of the named
 127  commit object, following only the first parent.  I.e. rev~3 is
 128  equivalent to rev{caret}{caret}{caret} which is equivalent to\
 129  rev{caret}1{caret}1{caret}1.
 130
 131* A suffix '{caret}' followed by an object type name enclosed in
 132  brace pair (e.g. `v0.99.8{caret}\{commit\}`) means the object
 133  could be a tag, and dereference the tag recursively until an
 134  object of that type is found or the object cannot be
 135  dereferenced anymore (in which case, barf).  `rev{caret}0`
 136  introduced earlier is a short-hand for `rev{caret}\{commit\}`.
 137
 138* A suffix '{caret}' followed by an empty brace pair
 139  (e.g. `v0.99.8{caret}\{\}`) means the object could be a tag,
 140  and dereference the tag recursively until a non-tag object is
 141  found.
 142
 143'git-rev-parse' also accepts a prefix '{caret}' to revision parameter,
 144which is passed to 'git-rev-list'.  Two revision parameters
 145concatenated with '..' is a short-hand for writing a range
 146between them.  I.e. 'r1..r2' is equivalent to saying '{caret}r1 r2'
 147
 148Here is an illustration, by Jon Loeliger.  Both node B and C are
 149a commit parents of commit node A.  Parent commits are ordered
 150left-to-right.
 151
 152    G   H   I   J
 153     \ /     \ /
 154      D   E   F
 155       \  |  /
 156        \ | /
 157         \|/
 158          B     C
 159           \   /
 160            \ /
 161             A
 162
 163    A =      = A^0
 164    B = A^   = A^1     = A~1
 165    C = A^2  = A^2
 166    D = A^^  = A^1^1   = A~2
 167    E = B^2  = A^^2
 168    F = B^3  = A^^3
 169    G = A^^^ = A^1^1^1 = A~3
 170    H = D^2  = B^^2    = A^^^2  = A~2^2
 171    I = F^   = B^3^    = A^^3^
 172    J = F^2  = B^3^2   = A^^3^2
 173
 174
 175Author
 176------
 177Written by Linus Torvalds <torvalds@osdl.org> and
 178Junio C Hamano <junkio@cox.net>
 179
 180Documentation
 181--------------
 182Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>.
 183
 184GIT
 185---
 186Part of the gitlink:git[7] suite
 187