1GIT-CHECK-REF-FOR(1) Git Manual GIT-CHECK-REF-FOR(1)
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6 git-check-ref-format - Ensures that a reference name is well formed
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9 git check-ref-format [--normalize]
10 [--[no-]allow-onelevel] [--refspec-pattern]
11 <refname>
12 git check-ref-format --branch <branchname-shorthand>
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15 Checks if a given refname is acceptable, and exits with a non-zero
16 status if it is not.
17 A reference is used in Git to specify branches and tags. A branch head
19 is stored in the refs/heads hierarchy, while a tag is stored in the
20 refs/tags hierarchy of the ref namespace (typically in
21 $GIT_DIR/refs/heads and $GIT_DIR/refs/tags directories or, as entries
22 in file $GIT_DIR/packed-refs if refs are packed by git gc).
23 Git imposes the following rules on how references are named:
25 1. They can include slash / for hierarchical (directory) grouping, but
27 no slash-separated component can begin with a dot . or end with
28 the sequence .lock.
29 2. They must contain at least one /. This enforces the presence of a
31 category like heads/, tags/ etc. but the actual names are not
32 restricted. If the --allow-onelevel option is used, this rule is
33 waived.
34 3. They cannot have two consecutive dots .. anywhere.
36 4. They cannot have ASCII control characters (i.e. bytes whose values
38 are lower than \040, or \177 DEL), space, tilde ~, caret ^, or
39 colon : anywhere.
40 5. They cannot have question-mark ?, asterisk *, or open bracket [
42 anywhere. See the --refspec-pattern option below for an exception
43 to this rule.
44 6. They cannot begin or end with a slash / or contain multiple
46 consecutive slashes (see the --normalize option below for an
47 exception to this rule)
48 7. They cannot end with a dot ..
50 8. They cannot contain a sequence @{.
52 9. They cannot be the single character @.
54 10. They cannot contain a \.
56 These rules make it easy for shell script based tools to parse
58 reference names, pathname expansion by the shell when a reference name
59 is used unquoted (by mistake), and also avoid ambiguities in certain
60 reference name expressions (see gitrevisions(7)):
61 1. A double-dot .. is often used as in ref1..ref2, and in some
63 contexts this notation means ^ref1 ref2 (i.e. not in ref1 and in
64 ref2).
65 2. A tilde ~ and caret ^ are used to introduce the postfix nth parent
67 and peel onion operation.
68 3. A colon : is used as in srcref:dstref to mean "use srcref’s value
70 and store it in dstref" in fetch and push operations. It may also
71 be used to select a specific object such as with 'git cat-file':
72 "git cat-file blob v1.3.3:refs.c".
73 4. at-open-brace @{ is used as a notation to access a reflog entry.
75 With the --branch option, the command takes a name and checks if it can
77 be used as a valid branch name (e.g. when creating a new branch). But
78 be cautious when using the previous checkout syntax that may refer to a
79 detached HEAD state. The rule git check-ref-format --branch $name
80 implements may be stricter than what git check-ref-format
81 refs/heads/$name says (e.g. a dash may appear at the beginning of a ref
82 component, but it is explicitly forbidden at the beginning of a branch
83 name). When run with --branch option in a repository, the input is
84 first expanded for the “previous checkout syntax” @{-n}. For example,
85 @{-1} is a way to refer the last thing that was checked out using "git
86 switch" or "git checkout" operation. This option should be used by
87 porcelains to accept this syntax anywhere a branch name is expected, so
88 they can act as if you typed the branch name. As an exception note
89 that, the “previous checkout operation” might result in a commit object
90 name when the N-th last thing checked out was not a branch.
91
93 --[no-]allow-onelevel
94 Controls whether one-level refnames are accepted (i.e., refnames
95 that do not contain multiple /-separated components). The default
96 is --no-allow-onelevel.
97 --refspec-pattern
99 Interpret <refname> as a reference name pattern for a refspec (as
100 used with remote repositories). If this option is enabled,
101 <refname> is allowed to contain a single * in the refspec (e.g.,
102 foo/bar*/baz or foo/bar*baz/ but not foo/bar*/baz*).
103 --normalize
105 Normalize refname by removing any leading slash (/) characters and
106 collapsing runs of adjacent slashes between name components into a
107 single slash. If the normalized refname is valid then print it to
108 standard output and exit with a status of 0, otherwise exit with a
109 non-zero status. (--print is a deprecated way to spell
110 --normalize.)
111
113 • Print the name of the previous thing checked out:
114 $ git check-ref-format --branch @{-1}
116 • Determine the reference name to use for a new branch:
118 $ ref=$(git check-ref-format --normalize "refs/heads/$newbranch")||
120 { echo "we do not like '$newbranch' as a branch name." >&2 ; exit 1 ; }
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123 Part of the git(1) suite
124Git 2.31.1 2021-03-26 GIT-CHECK-REF-FOR(1)