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man pages section 1: User Commands

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Updated: Wednesday, February 10, 2021

git-check-ref-format (1)


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


git check-ref-format [--normalize]
[--[no-]allow-onelevel] [--refspec-pattern]
git check-ref-format --branch <branchname-shorthand>


GIT-CHECK-REF-FOR(1)              Git Manual              GIT-CHECK-REF-FOR(1)

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

       git check-ref-format [--normalize]
              [--[no-]allow-onelevel] [--refspec-pattern]
       git check-ref-format --branch <branchname-shorthand>

       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

        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

        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). 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 --branch
       option in a repository, the input is first expanded for 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.

           Controls whether one-level refnames are accepted (i.e., refnames
           that do not contain multiple /-separated components). The default
           is --no-allow-onelevel.

           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 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

       o   Print the name of the previous branch:

               $ git check-ref-format --branch @{-1}

       o   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 ; }

       Part of the git(1) suite

Git 2.15.2                        05/29/2018              GIT-CHECK-REF-FOR(1)