git-check-ref-format(1) ======================= NAME ---- git-check-ref-format - Ensures that a reference name is well formed SYNOPSIS -------- [verse] 'git check-ref-format' [--normalize] [--[no-]allow-onelevel] [--refspec-pattern] <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 in the `refs/heads` hierarchy, while a tag is stored in the `refs/tags` hierarchy of the ref namespace (typically in `$GIT_DIR/refs/heads` and `$GIT_DIR/refs/tags` directories or, as entries in file `$GIT_DIR/packed-refs` if refs are packed by `git gc`). 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 `.` or end with the sequence `.lock`. . They must contain at least one `/`. This enforces the presence of a category like `heads/`, `tags/` etc. but the actual names are not restricted. If the `--allow-onelevel` option is used, this rule is waived. . 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 `^`, or colon `:` anywhere. . They cannot have question-mark `?`, asterisk `*`, or open bracket `[` anywhere. See the `--refspec-pattern` option below for an exception to this rule. . They cannot begin or end with a slash `/` or contain multiple consecutive slashes (see the `--normalize` option below for an exception to this rule). . They cannot end with a dot `.`. . They cannot contain a sequence `@{`. . They cannot be the single character `@`. . 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 avoid 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 `^ref1 ref2` (i.e. not in `ref1` and in `ref2`). . A tilde `~` and 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 `--branch` option, the command takes a name and checks if it can be used as a valid branch name (e.g. when creating a new branch). But be cautious when using the previous checkout syntax that may refer to a detached HEAD state. The rule `git check-ref-format --branch $name` implements may be stricter than what `git check-ref-format refs/heads/$name` says (e.g. a dash may appear at the beginning of a ref component, but it is explicitly forbidden at the beginning of a branch name). When run with the `--branch` option in a repository, the input is first expanded for the ``previous checkout syntax'' `@{-n}`. For example, `@{-1}` is a way to refer the last thing that was checked out using "git switch" or "git checkout" operation. 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. As an exception note that, the ``previous checkout operation'' might result in a commit object name when the N-th last thing checked out was not a branch. OPTIONS ------- --[no-]allow-onelevel:: Controls whether one-level refnames are accepted (i.e., refnames that do not contain multiple `/`-separated components). The default is `--no-allow-onelevel`. --refspec-pattern:: Interpret <refname> as a reference name pattern for a refspec (as used with remote repositories). If this option is enabled, <refname> is allowed to contain a single `*` in the refspec (e.g., `foo/bar*/baz` or `foo/bar*baz/` but not `foo/bar*/baz*`). --normalize:: Normalize 'refname' by removing any leading slash (`/`) characters and collapsing runs of adjacent slashes between name components into a single slash. If the normalized refname is valid then print it to standard output and exit with a status of 0, otherwise exit with a non-zero status. (`--print` is a deprecated way to spell `--normalize`.) EXAMPLES -------- * Print the name of the previous thing checked out: + ------------ $ git check-ref-format --branch @{-1} ------------ * Determine the reference name to use for a new branch: + ------------ $ ref=$(git check-ref-format --normalize "refs/heads/$newbranch")|| { echo "we do not like '$newbranch' as a branch name." >&2 ; exit 1 ; } ------------ GIT --- Part of the linkgit:git[1] suite