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" "$@")"
+----
+
--verify::
- The parameter given must be usable as a single, valid
- object name. Otherwise barf and abort.
+ Verify that exactly one parameter is provided, and that it
+ can be turned into a raw 20-byte SHA-1 that can be used to
+ access the object database. If so, emit it to the standard
+ output; otherwise, error out.
++
+If you want to make sure that the output actually names an object in
+your object database and/or can be used as a specific type of object
+you require, you can add "^{type}" peeling operator to the parameter.
+For example, `git rev-parse "$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::
* Print the commit object name from the revision in the $REV shell variable:
+
------------
-$ git rev-parse --verify $REV
+$ git rev-parse --verify $REV^{commit}
------------
+
This will error out if $REV is empty or not a valid revision.
-* Same as above:
+* Similar to above:
+
------------
$ git rev-parse --default master --verify $REV