Documentation / git-rev-parse.txton commit Delay "empty ident" errors until they really matter. (749be72)
   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--since=datestring, --after=datestring::
  81        Parses the date string, and outputs corresponding
  82        --max-age= parameter for git-rev-list command.
  83
  84--until=datestring, --before=datestring::
  85        Parses the date string, and outputs corresponding
  86        --min-age= parameter for git-rev-list command.
  87
  88<args>...::
  89        Flags and parameters to be parsed.
  90
  91
  92SPECIFYING REVISIONS
  93--------------------
  94
  95A revision parameter typically, but not necessarily, names a
  96commit object.  They use what is called an 'extended SHA1'
  97syntax.
  98
  99* The full SHA1 object name (40-byte hexadecimal string), or
 100  a substring of such that is unique within the repository.
 101  E.g. dae86e1950b1277e545cee180551750029cfe735 and dae86e both
 102  name the same commit object if there are no other object in
 103  your repository whose object name starts with dae86e.
 104
 105* A symbolic ref name.  E.g. 'master' typically means the commit
 106  object referenced by $GIT_DIR/refs/heads/master.  If you
 107  happen to have both heads/master and tags/master, you can
 108  explicitly say 'heads/master' to tell git which one you mean.
 109
 110* A suffix '{caret}' to a revision parameter means the first parent of
 111  that commit object.  '{caret}<n>' means the <n>th parent (i.e.
 112  'rev{caret}'
 113  is equivalent to 'rev{caret}1').  As a special rule,
 114  'rev{caret}0' means the commit itself and is used when 'rev' is the
 115  object name of a tag object that refers to a commit object.
 116
 117* A suffix '~<n>' to a revision parameter means the commit
 118  object that is the <n>th generation grand-parent of the named
 119  commit object, following only the first parent.  I.e. rev~3 is
 120  equivalent to rev{caret}{caret}{caret} which is equivalent to\
 121  rev{caret}1{caret}1{caret}1.
 122
 123* A suffix '{caret}' followed by an object type name enclosed in
 124  brace pair (e.g. `v0.99.8{caret}\{commit\}`) means the object
 125  could be a tag, and dereference the tag recursively until an
 126  object of that type is found or the object cannot be
 127  dereferenced anymore (in which case, barf).  `rev{caret}0`
 128  introduced earlier is a short-hand for `rev{caret}\{commit\}`.
 129
 130* A suffix '{caret}' followed by an empty brace pair
 131  (e.g. `v0.99.8{caret}\{\}`) means the object could be a tag,
 132  and dereference the tag recursively until a non-tag object is
 133  found.
 134
 135'git-rev-parse' also accepts a prefix '{caret}' to revision parameter,
 136which is passed to 'git-rev-list'.  Two revision parameters
 137concatenated with '..' is a short-hand for writing a range
 138between them.  I.e. 'r1..r2' is equivalent to saying '{caret}r1 r2'
 139
 140Here is an illustration, by Jon Loeliger.  Both node B and C are
 141a commit parents of commit node A.  Parent commits are ordered
 142left-to-right.
 143
 144    G   H   I   J
 145     \ /     \ /
 146      D   E   F
 147       \  |  /
 148        \ | /
 149         \|/
 150          B     C
 151           \   /
 152            \ /
 153             A
 154
 155    A =      = A^0
 156    B = A^   = A^1     = A~1
 157    C = A^2  = A^2
 158    D = A^^  = A^1^1   = A~2
 159    E = B^2  = A^^2
 160    F = B^3  = A^^3
 161    G = A^^^ = A^1^1^1 = A~3
 162    H = D^2  = B^^2    = A^^^2  = A~2^2
 163    I = F^   = B^3^    = A^^3^
 164    J = F^2  = B^3^2   = A^^3^2
 165
 166
 167Author
 168------
 169Written by Linus Torvalds <torvalds@osdl.org> and
 170Junio C Hamano <junkio@cox.net>
 171
 172Documentation
 173--------------
 174Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>.
 175
 176GIT
 177---
 178Part of the gitlink:git[7] suite
 179