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