# git-check-ref-format

## NAME



           git-check-ref-format - Ensures that a reference name is well
           formed
    


## SYNOPSIS



           _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:
    
            1. They can include slash **/** for hierarchical (directory)
               grouping, but no slash-separated component can begin with a
               dot . or end with the sequence **.lock**.
    
            2. 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.
    
            3. They cannot have two consecutive dots .. anywhere.
    
            4. They cannot have ASCII control characters (i.e. bytes whose
               values are lower than \040, or \177 **DEL**), space, tilde **~** ,
               caret **^** , or colon **:** anywhere.
    
            5. They cannot have question-mark ?, asterisk ***** , or open bracket
               [ anywhere. See the **--refspec-pattern** option below for an
               exception to this rule.
    
            6. They cannot begin or end with a slash **/** or contain multiple
               consecutive slashes (see the **--normalize** option below for an
               exception to this rule).
    
            7. They cannot end with a dot ..
    
            8. They cannot contain a sequence **@**{.
    
            9. They cannot be the single character **@**.
    
           10. 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 gitrevisions(7)):
    
            1. 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**).
    
            2. A tilde **~** and caret **^** are used to introduce the postfix _nth_
               _parent_ and _peel onion_ operation.
    
            3. 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".
    
            4. 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 git(1) suite
    


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