git-rev-parse - Online in the Cloud

PROGRAM:

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

Operation Modes
Each of these options must appear first on the command line.

--parseopt
Use git rev-parse in option parsing mode (see PARSEOPT section below).

--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.

Options for --parseopt
--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.

--stuck-long
Only meaningful in --parseopt mode. Output the options in their long form if
available, and with their arguments stuck.

Options for Filtering
--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.

Options for Output
--default <arg>
If there is no parameter given by the user, use <arg> instead.

--prefix <arg>
Behave as if git rev-parse was invoked from the <arg> subdirectory of the working
tree. Any relative filenames are resolved as if they are prefixed by <arg> and will be
printed in that form.

This can be used to convert arguments to a command run in a subdirectory so that they
can still be used after moving to the top-level of the repository. For example:

prefix=$(git rev-parse --show-prefix)
cd "$(git rev-parse --show-toplevel)"
eval "set -- $(git rev-parse --sq --prefix "$prefix" "$@")"

--verify
Verify that exactly one parameter is provided, and that it can be turned into a raw
20-byte SHA-1 that can be used to access the object database. If so, emit it to the
standard output; otherwise, error out.

If you want to make sure that the output actually names an object in your object
database and/or can be used as a specific type of object you require, you can add the
^{type} peeling operator to the parameter. For example, git rev-parse "$VAR^{commit}"
will make sure $VAR names an existing object that is a commit-ish (i.e. a commit, or
an annotated tag that points at a commit). To make sure that $VAR names an existing
object of any type, git rev-parse "$VAR^{object}" can be used.

-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. SHA-1s for
valid object names are printed to stdout on success.

--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.

--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.

--short, --short=number
Instead of outputting the full SHA-1 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.

--symbolic
Usually the object names are output in SHA-1 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").

Options for Objects
--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 /*.

--exclude=<glob-pattern>
Do not include refs matching <glob-pattern> that the next --all, --branches, --tags,
--remotes, or --glob would otherwise consider. Repetitions of this option accumulate
exclusion patterns up to the next --all, --branches, --tags, --remotes, or --glob
option (other options or arguments do not clear accumulated patterns).

The patterns given should not begin with refs/heads, refs/tags, or refs/remotes when
applied to --branches, --tags, or --remotes, respectively, and they must begin with
refs/ when applied to --glob or --all. If a trailing /* is intended, it must be given
explicitly.

--disambiguate=<prefix>
Show every object whose name begins with the given prefix. The <prefix> must be at
least 4 hexadecimal digits long to avoid listing each and every object in the
repository by mistake.

Options for Files
--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.

--git-dir
Show $GIT_DIR if defined. Otherwise show the path to the .git directory. The path
shown, when relative, is relative to the current working directory.

If $GIT_DIR is not defined and the current directory is not detected to lie in a Git
repository or work tree print a message to stderr and exit with nonzero status.

--git-common-dir
Show $GIT_COMMON_DIR if defined, else $GIT_DIR.

--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".

--resolve-git-dir <path>
Check if <path> is a valid repository or a gitfile that points at a valid repository,
and print the location of the repository. If <path> is a gitfile then the resolved
path to the real repository is printed.

--git-path <path>
Resolve "$GIT_DIR/<path>" and takes other path relocation variables such as
$GIT_OBJECT_DIRECTORY, $GIT_INDEX_FILE... into account. For example, if
$GIT_OBJECT_DIRECTORY is set to /foo/bar then "git rev-parse --git-path objects/abc"
returns /foo/bar/abc.

--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).

--show-prefix
When the command is invoked from a subdirectory, show the path of the current
directory relative to the top-level directory.

--show-toplevel
Show the absolute path of the top-level directory.

--shared-index-path
Show the path to the shared index file in split index mode, or empty if not in
split-index mode.

Other Options
--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 <rev> typically, but not necessarily, names a commit object. It uses
what is called an extended SHA-1 syntax. Here are various ways to spell object names. The
ones listed near the end of this list name trees and blobs contained in a commit.

<sha1>, e.g. dae86e1950b1277e545cee180551750029cfe735, dae86e
The full SHA-1 object name (40-byte hexadecimal string), or a leading substring that
is unique within the repository. E.g. dae86e1950b1277e545cee180551750029cfe735 and
dae86e both name the same commit object if there is no other object in your repository
whose object name starts with dae86e.

<describeOutput>, e.g. v1.7.4.2-679-g3bee7fb
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.

<refname>, e.g. master, heads/master, refs/heads/master
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
<refname> is disambiguated by taking the first match in the following rules:

1. If $GIT_DIR/<refname> exists, that is what you mean (this is usually useful only
for HEAD, FETCH_HEAD, ORIG_HEAD, MERGE_HEAD and CHERRY_PICK_HEAD);

2. otherwise, refs/<refname> if it exists;

3. otherwise, refs/tags/<refname> if it exists;

4. otherwise, refs/heads/<refname> if it exists;

5. otherwise, refs/remotes/<refname> if it exists;

6. otherwise, refs/remotes/<refname>/HEAD if it exists.

HEAD names the commit on which you based the changes in the working tree.
FETCH_HEAD records the branch which you fetched from a remote repository with your
last git fetch invocation. ORIG_HEAD is created by commands that move your HEAD
in a drastic way, to record the position of the HEAD before their operation, so
that you can easily change the tip of the branch back to the state before you ran
them. MERGE_HEAD records the commit(s) which you are merging into your branch
when you run git merge. CHERRY_PICK_HEAD records the commit which you are
cherry-picking when you run git cherry-pick.

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. While the ref name encoding is
unspecified, UTF-8 is preferred as some output processing may assume ref names in
UTF-8.

@
@ alone is a shortcut for HEAD.

<refname>@{<date>}, e.g. master@{yesterday}, HEAD@{5 minutes ago}
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}) specifies 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.

<refname>@{<n>}, e.g. master@{1}
A ref followed by the suffix @ with an ordinal specification enclosed in a brace pair
(e.g. {1}, {15}) specifies 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/<refname>).

@{<n>}, e.g. @{1}
You can use the @ construct with an empty ref part to get at a reflog entry of the
current branch. For example, if you are on branch blabla then @{1} means the same as
blabla@{1}.

@{-<n>}, e.g. @{-1}
The construct @{-<n>} means the <n>th branch/commit checked out before the current
one.

<branchname>@{upstream}, e.g. master@{upstream}, @{u}
The suffix @{upstream} to a branchname (short form <branchname>@{u}) refers to the
branch that the branch specified by branchname is set to build on top of (configured
with branch.<name>.remote and branch.<name>.merge). A missing branchname defaults to
the current one.

<branchname>@{push}, e.g. master@{push}, @{push}
The suffix @{push} reports the branch "where we would push to" if git push were run
while branchname was checked out (or the current HEAD if no branchname is specified).
Since our push destination is in a remote repository, of course, we report the local
tracking branch that corresponds to that branch (i.e., something in refs/remotes/).

Here’s an example to make it more clear:

$ git config push.default current
$ git config remote.pushdefault myfork
$ git checkout -b mybranch origin/master

$ git rev-parse --symbolic-full-name @{upstream}
refs/remotes/origin/master

$ git rev-parse --symbolic-full-name @{push}
refs/remotes/myfork/mybranch

Note in the example that we set up a triangular workflow, where we pull from one
location and push to another. In a non-triangular workflow, @{push} is the same as
@{upstream}, and there is no need for it.

<rev>^, e.g. HEAD^, v1.5.1^0
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.

<rev>~<n>, e.g. master~3
A suffix ~<n> to a revision parameter means the commit object that is the <n>th
generation ancestor of the named commit object, following only the first parents. I.e.
<rev>~3 is equivalent to <rev>^^^ which is equivalent to <rev>^1^1^1. See below for an
illustration of the usage of this form.

<rev>^{<type>}, e.g. v0.99.8^{commit}
A suffix ^ followed by an object type name enclosed in brace pair means dereference
the object at <rev> recursively until an object of type <type> is found or the object
cannot be dereferenced anymore (in which case, barf). For example, if <rev> is a
commit-ish, <rev>^{commit} describes the corresponding commit object. Similarly, if
<rev> is a tree-ish, <rev>^{tree} describes the corresponding tree object. <rev>^0 is
a short-hand for <rev>^{commit}.

rev^{object} can be used to make sure rev names an object that exists, without
requiring rev to be a tag, and without dereferencing rev; because a tag is already an
object, it does not have to be dereferenced even once to get to an object.

rev^{tag} can be used to ensure that rev identifies an existing tag object.

<rev>^{}, e.g. v0.99.8^{}
A suffix ^ followed by an empty brace pair means the object could be a tag, and
dereference the tag recursively until a non-tag object is found.

<rev>^{/<text>}, e.g. HEAD^{/fix nasty bug}
A suffix ^ to a revision parameter, followed by a brace pair that contains a text led
by a slash, is the same as the :/fix nasty bug syntax below except that it returns the
youngest matching commit which is reachable from the <rev> before ^.

:/<text>, e.g. :/fix nasty bug
A colon, followed by a slash, followed by a text, names a commit whose commit message
matches the specified regular expression. 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. The regular expression can match any part of the commit message. To
match messages starting with a string, one can use e.g. :/^foo.

<rev>:<path>, e.g. HEAD:README, :README, master:./README
A suffix : followed by a path names the blob or tree at the given path in the tree-ish
object named by the part before the colon. :path (with an empty part before the
colon) is a special case of the syntax described next: content recorded in the index
at the given path. A path starting with ./ or ../ is relative to the current working
directory. The given path will be converted to be relative to the working tree’s root
directory. This is most useful to address a blob or tree from a commit or tree that
has the same tree structure as the working tree.

:<n>:<path>, e.g. :0:README, :README
A colon, optionally followed by a stage number (0 to 3) and a colon, followed by a
path, names a blob object in the index at the given path. A 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 which is 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.

In these two shorthands, you can omit one end and let it default to HEAD. For example,
origin.. is a shorthand for origin..HEAD and asks "What did I do since I forked from the
origin branch?" Similarly, ..origin is a shorthand for HEAD..origin and asks "What did the
origin do since I forked from them?" Note that .. would mean HEAD..HEAD which is an empty
range that is both reachable and unreachable from HEAD.

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.

To summarize:

<rev>
Include commits that are reachable from (i.e. ancestors of) <rev>.

^<rev>
Exclude commits that are reachable from (i.e. ancestors of) <rev>.

<rev1>..<rev2>
Include commits that are reachable from <rev2> but exclude those that are reachable
from <rev1>. When either <rev1> or <rev2> is omitted, it defaults to HEAD.

<rev1>...<rev2>
Include commits that are reachable from either <rev1> or <rev2> but exclude those that
are reachable from both. When either <rev1> or <rev2> is omitted, it defaults to HEAD.

<rev>^@, e.g. HEAD^@
A suffix ^ followed by an at sign is the same as listing all parents of <rev>
(meaning, include anything reachable from its parents, but not the commit itself).

<rev>^!, e.g. HEAD^!
A suffix ^ followed by an exclamation mark is the same as giving commit <rev> and then
all its parents prefixed with ^ to exclude them (and their ancestors).

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 C
B...C G H D E B C
^D B C E I J F B C
C I J F C
C^@ I J F
C^! C
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 string 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.

Note: Make sure you quote the result when passing it to eval. See below for an example.

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 one or more) are
used for the usage. The lines after the separator describe the options.

Each line of options has this format:

<opt-spec><flags>*<arg-hint>? 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. May not contain
any of the <flags> characters. h,help, dry-run and f are examples of correct
<opt-spec>.

<flags>
<flags> are of *, =, ? or !.

· Use = if the option takes an argument.

· Use ? to mean that the option takes an optional argument. You probably want to
use the --stuck-long mode to be able to unambiguously parse the optional argument.

· 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).

· Use ! to not make the corresponding negated long option available.

<arg-hint>
<arg-hint>, if specified, is used as a name of the argument in the help output, for
options that take arguments. <arg-hint> is terminated by the first whitespace. It is
customary to use a dash to separate words in a multi-word argument hint.

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
baz=arg another cool option --baz with a named argument
qux?path qux may take a path argument but has meaning by itself

An option group Header
C? option C with an optional argument"

eval "$(echo "$OPTS_SPEC" | git rev-parse --parseopt -- "$@" || echo exit $?)"

Usage text
When "$@" is -h or --help in the above example, the following usage text would be shown:

usage: 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
--baz <arg> another cool option --baz with a named argument
--qux[=<path>] qux may take a path argument but has meaning by itself

An option group Header
-C[...] option C with an optional argument

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

· Print the object name of the current commit:

$ git rev-parse --verify HEAD

· Print the commit object name from the revision in the $REV shell variable:

$ git rev-parse --verify $REV^{commit}

This will error out if $REV is empty or not a valid revision.

· Similar to above:

$ git rev-parse --default master --verify $REV

but if $REV is empty, the commit object name from master will be printed.

GIT

Part of the git(1) suite

Use git-rev-parse online using onworks.net services