--------
[verse]
'git check-ref-format' <refname>
-'git check-ref-format' [--branch] <branchname-shorthand>
+'git check-ref-format' --print <refname>
+'git check-ref-format' --branch <branchname-shorthand>
DESCRIPTION
-----------
A reference is used in git to specify branches and tags. A
branch head is stored under the `$GIT_DIR/refs/heads` directory, and
-a tag is stored under the `$GIT_DIR/refs/tags` directory. git
-imposes the following rules on how references are named:
+a tag is stored under the `$GIT_DIR/refs/tags` directory (or, if refs
+are packed by `git gc`, as entries in the `$GIT_DIR/packed-refs` file).
+git imposes the following rules on how references are named:
. They can include slash `/` for hierarchical (directory)
grouping, but no slash-separated component can begin with a
dot `.`.
+. They must contain at least one `/`. This enforces the presence of a
+ category like `heads/`, `tags/` etc. but the actual names are not
+ restricted.
+
. They cannot have two consecutive dots `..` anywhere.
. They cannot have ASCII control characters (i.e. bytes whose
. They cannot contain a sequence `@{`.
+. They cannot contain a `\`.
+
These rules make it easy for shell script based tools to parse
reference names, pathname expansion by the shell when a reference name is used
unquoted (by mistake), and also avoids ambiguities in certain
. A colon `:` is used as in `srcref:dstref` to mean "use srcref\'s
value and store it in dstref" in fetch and push operations.
It may also be used to select a specific object such as with
- 'git-cat-file': "git cat-file blob v1.3.3:refs.c".
+ 'git cat-file': "git cat-file blob v1.3.3:refs.c".
. at-open-brace `@{` is used as a notation to access a reflog entry.
-With the `--branch` option, it expands a branch name shorthand and
-prints the name of the branch the shorthand refers to.
+With the `--print` option, if 'refname' is acceptable, it prints the
+canonicalized name of a hypothetical reference with that name. That is,
+it prints 'refname' with any extra `/` characters removed.
-EXAMPLE
--------
+With the `--branch` option, it expands the ``previous branch syntax''
+`@{-n}`. For example, `@{-1}` is a way to refer the last branch you
+were on. This option should be used by porcelains to accept this
+syntax anywhere a branch name is expected, so they can act as if you
+typed the branch name.
-git check-ref-format --branch @{-1}::
-
-Print the name of the previous branch.
+EXAMPLES
+--------
+* Print the name of the previous branch:
++
+------------
+$ git check-ref-format --branch @{-1}
+------------
+
+* Determine the reference name to use for a new branch:
++
+------------
+$ ref=$(git check-ref-format --print "refs/heads/$newbranch") ||
+die "we do not like '$newbranch' as a branch name."
+------------
GIT
---