SYNOPSIS
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:
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They can include slash / for hierarchical (directory) grouping, but no slash-separated component can begin with a dot ..
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They must contain at least one /. This enforces the presence of a category like heads/, tags/ etc. but the actual names are not restricted.
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They cannot have two consecutive dots .. anywhere.
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They cannot have ASCII control characters (i.e. bytes whose values are lower than \040, or \177 DEL), space, tilde ~, caret ^, colon :, question-mark ?, asterisk *, or open bracket [ anywhere.
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They cannot end with a slash / nor a dot ..
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They cannot end with the sequence .lock.
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They cannot contain a sequence @{.
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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 gitrevisions(7)):
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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).
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A tilde ~ and caret ^ are used to introduce the postfix nth parent and peel onion operation.
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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".
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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
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Print the name of the previous branch:
$ git check-ref-format --branch @{-1}
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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 git(1) suite