git-check-ref-format(1) — Linux manual page


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

NAME         top

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

SYNOPSIS         top

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

DESCRIPTION         top

       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

       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

       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
       --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         top

           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

           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         top

       •   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         top

       Part of the git(1) suite

COLOPHON         top

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       system) project.  Information about the project can be found at
       ⟨⟩.  If you have a bug report for this manual
       page, see ⟨⟩.  This page was obtained
       from the project's upstream Git repository
       ⟨⟩ on 2021-08-27.  (At that time,
       the date of the most recent commit that was found in the
       repository was 2021-08-24.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to

Git         08/27/2021           GIT-CHECK-REF-FOR(1)

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