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+git-check-ref-format(1)
+=======================
+
+NAME
+----
+git-check-ref-format - Ensures that a reference name is well formed
+
+SYNOPSIS
+--------
+[verse]
+'git check-ref-format' <refname>
+'git check-ref-format' --print <refname>
+'git check-ref-format' --branch <branchname-shorthand>
+
+DESCRIPTION
+-----------
+Checks if a given 'refname' is acceptable, and exits with a non-zero
+status if it is not.
+
+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 (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
+  values are lower than \040, or \177 `DEL`), space, tilde `~`,
+  caret `{caret}`, colon `:`, question-mark `?`, asterisk `*`,
+  or open bracket `[` anywhere.
+
+. They cannot end with a slash `/` nor a dot `.`.
+
+. They cannot end with the sequence `.lock`.
+
+. 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
+reference name expressions (see linkgit:gitrevisions[7]):
+
+. A double-dot `..` is often used as in `ref1..ref2`, and in some
+  contexts this notation means `{caret}ref1 ref2` (i.e. not in
+  `ref1` and in `ref2`).
+
+. A tilde `~` and caret `{caret}` are used to introduce the postfix
+  'nth parent' and 'peel onion' operation.
+
+. 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".
+
+. at-open-brace `@{` is used as a notation to access a reflog entry.
+
+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.
+
+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.
+
+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
+---
+Part of the linkgit:git[1] suite