NAME
git-rev-parse - Pick out and massage parameters
SYNOPSIS
git rev-parse [ --option ] <args>...
DESCRIPTION
Many git porcelainish commands take mixture of flags (i.e. parameters
that begin with a dash -) and parameters meant for the underlying git
rev-list command they use internally and flags and parameters for the
other commands they use downstream of git rev-list. This command is
used to distinguish between them.
OPTIONS
--parseopt
Use git rev-parse in option parsing mode (see PARSEOPT section
below).
--keep-dashdash
Only meaningful in --parseopt mode. Tells the option parser to echo
out the first -- met instead of skipping it.
--stop-at-non-option
Only meaningful in --parseopt mode. Lets the option parser stop at
the first non-option argument. This can be used to parse
sub-commands that take options themselves.
--sq-quote
Use git rev-parse in shell quoting mode (see SQ-QUOTE section
below). In contrast to the --sq option below, this mode does only
quoting. Nothing else is done to command input.
--revs-only
Do not output flags and parameters not meant for git rev-list
command.
--no-revs
Do not output flags and parameters meant for git rev-list command.
--flags
Do not output non-flag parameters.
--no-flags
Do not output flag parameters.
--default <arg>
If there is no parameter given by the user, use <arg> instead.
--verify
The parameter given must be usable as a single, valid object name.
Otherwise barf and abort.
-q, --quiet
Only meaningful in --verify mode. Do not output an error message if
the first argument is not a valid object name; instead exit with
non-zero status silently.
--sq
Usually the output is made one line per flag and parameter. This
option makes output a single line, properly quoted for consumption
by shell. Useful when you expect your parameter to contain
whitespaces and newlines (e.g. when using pickaxe -S with git
diff-\*). In contrast to the --sq-quote option, the command input
is still interpreted as usual.
--not
When showing object names, prefix them with ^ and strip ^ prefix
from the object names that already have one.
--symbolic
Usually the object names are output in SHA1 form (with possible ^
prefix); this option makes them output in a form as close to the
original input as possible.
--symbolic-full-name
This is similar to --symbolic, but it omits input that are not refs
(i.e. branch or tag names; or more explicitly disambiguating
"heads/master" form, when you want to name the "master" branch when
there is an unfortunately named tag "master"), and show them as
full refnames (e.g. "refs/heads/master").
--abbrev-ref[={strict|loose}]
A non-ambiguous short name of the objects name. The option
core.warnAmbiguousRefs is used to select the strict abbreviation
mode.
--all
Show all refs found in refs/.
--branches[=pattern], --tags[=pattern], --remotes[=pattern]
Show all branches, tags, or remote-tracking branches, respectively
(i.e., refs found in refs/heads, refs/tags, or refs/remotes,
respectively).
If a pattern is given, only refs matching the given shell glob are
shown. If the pattern does not contain a globbing character (?, *,
or [), it is turned into a prefix match by appending /\*.
--glob=pattern
Show all refs matching the shell glob pattern pattern. If the
pattern does not start with refs/, this is automatically prepended.
If the pattern does not contain a globbing character (?, *, or [),
it is turned into a prefix match by appending /\*.
--show-toplevel
Show the absolute path of the top-level directory.
--show-prefix
When the command is invoked from a subdirectory, show the path of
the current directory relative to the top-level directory.
--show-cdup
When the command is invoked from a subdirectory, show the path of
the top-level directory relative to the current directory
(typically a sequence of "../", or an empty string).
--git-dir
Show $GIT_DIR if defined else show the path to the .git directory.
--is-inside-git-dir
When the current working directory is below the repository
directory print "true", otherwise "false".
--is-inside-work-tree
When the current working directory is inside the work tree of the
repository print "true", otherwise "false".
--is-bare-repository
When the repository is bare print "true", otherwise "false".
--local-env-vars
List the GIT_* environment variables that are local to the
repository (e.g. GIT_DIR or GIT_WORK_TREE, but not GIT_EDITOR).
Only the names of the variables are listed, not their value, even
if they are set.
--short, --short=number
Instead of outputting the full SHA1 values of object names try to
abbreviate them to a shorter unique name. When no length is
specified 7 is used. The minimum length is 4.
--since=datestring, --after=datestring
Parse the date string, and output the corresponding --max-age=
parameter for git rev-list.
--until=datestring, --before=datestring
Parse the date string, and output the corresponding --min-age=
parameter for git rev-list.
<args>...
Flags and parameters to be parsed.
SPECIFYING REVISIONS
A revision parameter typically, but not necessarily, names a commit
object. They use what is called an extended SHA1 syntax. Here are
various ways to spell object names. The ones listed near the end of
this list are to name trees and blobs contained in a commit.
o The full SHA1 object name (40-byte hexadecimal string), or a
substring of such that is unique within the repository. E.g.
dae86e1950b1277e545cee180551750029cfe735 and dae86e both name the
same commit object if there are no other object in your repository
whose object name starts with dae86e.
o An output from git describe; i.e. a closest tag, optionally
followed by a dash and a number of commits, followed by a dash, a
g, and an abbreviated object name.
o A symbolic ref name. E.g. master typically means the commit object
referenced by refs/heads/master. If you happen to have both
heads/master and tags/master, you can explicitly say heads/master
to tell git which one you mean. When ambiguous, a <name> is
disambiguated by taking the first match in the following rules:
1. if $GIT_DIR/<name> exists, that is what you mean (this is
usually useful only for HEAD, FETCH_HEAD, ORIG_HEAD and
MERGE_HEAD);
2. otherwise, refs/<name> if exists;
3. otherwise, refs/tags/<name> if exists;
4. otherwise, refs/heads/<name> if exists;
5. otherwise, refs/remotes/<name> if exists;
6. otherwise, refs/remotes/<name>/HEAD if exists.
HEAD names the commit your changes in the working tree is based
on. FETCH_HEAD records the branch you fetched from a remote
repository with your last git fetch invocation. ORIG_HEAD is
created by commands that moves your HEAD in a drastic way, to
record the position of the HEAD before their operation, so that
you can change the tip of the branch back to the state before
you ran them easily. MERGE_HEAD records the commit(s) you are
merging into your branch when you run git merge.
Note that any of the refs/* cases above may come either from
the $GIT_DIR/refs directory or from the $GIT_DIR/packed-refs
file.
o A ref followed by the suffix @ with a date specification enclosed
in a brace pair (e.g. {yesterday}, {1 month 2 weeks 3 days 1 hour
1 second ago} or {1979-02-26 18:30:00}) to specify the value of the
ref at a prior point in time. This suffix may only be used
immediately following a ref name and the ref must have an existing
log ($GIT_DIR/logs/<ref>). Note that this looks up the state of
your local ref at a given time; e.g., what was in your local master
branch last week. If you want to look at commits made during
certain times, see --since and --until.
o A ref followed by the suffix @ with an ordinal specification
enclosed in a brace pair (e.g. {1}, {15}) to specify the n-th
prior value of that ref. For example master@{1} is the immediate
prior value of master while master@{5} is the 5th prior value of
master. This suffix may only be used immediately following a ref
name and the ref must have an existing log ($GIT_DIR/logs/<ref>).
o You can use the @ construct with an empty ref part to get at a
reflog of the current branch. For example, if you are on the branch
blabla, then @{1} means the same as blabla@{1}.
o The special construct @{-<n>} means the <n>th branch checked out
before the current one.
o The suffix @{upstream} to a ref (short form ref@{u}) refers to the
branch the ref is set to build on top of. Missing ref defaults to
the current branch.
o A suffix ^ to a revision parameter means the first parent of that
commit object. ^<n> means the <n>th parent (i.e. rev^ is
equivalent to rev^1). As a special rule, rev^0 means the commit
itself and is used when rev is the object name of a tag object that
refers to a commit object.
o A suffix ~<n> to a revision parameter means the commit object that
is the <n>th generation grand-parent of the named commit object,
following only the first parent. I.e. rev~3 is equivalent to rev^^^
which is equivalent to rev^1^1^1. See below for a illustration of
the usage of this form.
o A suffix ^ followed by an object type name enclosed in brace pair
(e.g. v0.99.8^{commit}) means the object could be a tag, and
dereference the tag recursively until an object of that type is
found or the object cannot be dereferenced anymore (in which case,
barf). rev^0 introduced earlier is a short-hand for rev^{commit}.
o A suffix ^ followed by an empty brace pair (e.g. v0.99.8^{}) means
the object could be a tag, and dereference the tag recursively
until a non-tag object is found.
o A colon, followed by a slash, followed by a text: this names a
commit whose commit message starts with the specified text. This
name returns the youngest matching commit which is reachable from
any ref. If the commit message starts with a !, you have to repeat
that; the special sequence :/!, followed by something else than !
is reserved for now.
o A suffix : followed by a path; this names the blob or tree at the
given path in the tree-ish object named by the part before the
colon.
o A colon, optionally followed by a stage number (0 to 3) and a
colon, followed by a path; this names a blob object in the index at
the given path. Missing stage number (and the colon that follows
it) names a stage 0 entry. During a merge, stage 1 is the common
ancestor, stage 2 is the target branch's version (typically the
current branch), and stage 3 is the version from the branch being
merged.
Here is an illustration, by Jon Loeliger. Both commit nodes B and C are
parents of commit node A. Parent commits are ordered left-to-right.
G H I J
\ / \ /
D E F
\ | / \
\ | / |
\|/ |
B C
\ /
\ /
A
A = = A^0
B = A^ = A^1 = A~1
C = A^2 = A^2
D = A^^ = A^1^1 = A~2
E = B^2 = A^^2
F = B^3 = A^^3
G = A^^^ = A^1^1^1 = A~3
H = D^2 = B^^2 = A^^^2 = A~2^2
I = F^ = B^3^ = A^^3^
J = F^2 = B^3^2 = A^^3^2
SPECIFYING RANGES
History traversing commands such as git log operate on a set of
commits, not just a single commit. To these commands, specifying a
single revision with the notation described in the previous section
means the set of commits reachable from that commit, following the
commit ancestry chain.
To exclude commits reachable from a commit, a prefix ^ notation is
used. E.g. ^r1 r2 means commits reachable from r2 but exclude the ones
reachable from r1.
This set operation appears so often that there is a shorthand for it.
When you have two commits r1 and r2 (named according to the syntax
explained in SPECIFYING REVISIONS above), you can ask for commits that
are reachable from r2 excluding those that are reachable from r1 by ^r1
r2 and it can be written as r1..r2.
A similar notation r1...r2 is called symmetric difference of r1 and r2
and is defined as r1 r2 --not $(git merge-base --all r1 r2). It is the
set of commits that are reachable from either one of r1 or r2 but not
from both.
Two other shorthands for naming a set that is formed by a commit and
its parent commits exist. The r1^@ notation means all parents of r1.
r1^! includes commit r1 but excludes all of its parents.
Here are a handful of examples:
D G H D
D F G H I J D F
^G D H D
^D B E I J F B
B...C G H D E B C
^D B C E I J F B C
C^@ I J F
F^! D G H D F
PARSEOPT
In --parseopt mode, git rev-parse helps massaging options to bring to
shell scripts the same facilities C builtins have. It works as an
option normalizer (e.g. splits single switches aggregate values), a bit
like getopt(1) does.
It takes on the standard input the specification of the options to
parse and understand, and echoes on the standard output a line suitable
for sh(1) eval to replace the arguments with normalized ones. In case
of error, it outputs usage on the standard error stream, and exits with
code 129.
Input Format
git rev-parse --parseopt input format is fully text based. It has two
parts, separated by a line that contains only --. The lines before the
separator (should be more than one) are used for the usage. The lines
after the separator describe the options.
Each line of options has this format:
<opt_spec><flags>* SP+ help LF
<opt_spec>
its format is the short option character, then the long option name
separated by a comma. Both parts are not required, though at least
one is necessary. h,help, dry-run and f are all three correct
<opt_spec>.
<flags>
<flags> are of *, =, ? or !.
o Use = if the option takes an argument.
o Use ? to mean that the option is optional (though its use is
discouraged).
o Use * to mean that this option should not be listed in the
usage generated for the -h argument. It's shown for --help-all
as documented in gitcli(7).
o Use ! to not make the corresponding negated long option
available.
The remainder of the line, after stripping the spaces, is used as the
help associated to the option.
Blank lines are ignored, and lines that don't match this specification
are used as option group headers (start the line with a space to create
such lines on purpose).
Example
OPTS_SPEC="\
some-command [options] <args>...
some-command does foo and bar!
--
h,help show the help
foo some nifty option --foo
bar= some cool option --bar with an argument
An option group Header
C? option C with an optional argument"
eval `echo "$OPTS_SPEC" | git rev-parse --parseopt -- "$@" || echo exit $?`
SQ-QUOTE
In --sq-quote mode, git rev-parse echoes on the standard output a
single line suitable for sh(1) eval. This line is made by normalizing
the arguments following --sq-quote. Nothing other than quoting the
arguments is done.
If you want command input to still be interpreted as usual by git
rev-parse before the output is shell quoted, see the --sq option.
Example
$ cat >your-git-script.sh <<\EOF
#!/bin/sh
args=$(git rev-parse --sq-quote "$@") # quote user-supplied arguments
command="git frotz -n24 $args" # and use it inside a handcrafted
# command line
eval "$command"
EOF
$ sh your-git-script.sh "a b'c"
EXAMPLES
o Print the object name of the current commit:
$ git rev-parse --verify HEAD
o Print the commit object name from the revision in the $REV shell
variable:
$ git rev-parse --verify $REV
This will error out if $REV is empty or not a valid revision.
o Same as above:
$ git rev-parse --default master --verify $REV
but if $REV is empty, the commit object name from master will be
printed.
AUTHOR
Written by Linus Torvalds <torvalds@osdl.org[1]> . Junio C Hamano
<gitster@pobox.com[2]> and Pierre Habouzit <madcoder@debian.org[3]>
DOCUMENTATION
Documentation by Junio C Hamano and the git-list
<git@vger.kernel.org[4]>.
GIT
Part of the git(1) suite
NOTES
1. torvalds@osdl.org
mailto:torvalds@osdl.org
2. gitster@pobox.com
mailto:gitster@pobox.com
3. madcoder@debian.org
mailto:madcoder@debian.org
4. git@vger.kernel.org
mailto:git@vger.kernel.org