1git-check-ref-format(1) 2======================= 3 4NAME 5---- 6git-check-ref-format - Ensures that a reference name is well formed 7 8SYNOPSIS 9-------- 10[verse] 11'git check-ref-format' [--normalize] 12 [--[no-]allow-onelevel] [--refspec-pattern] 13 <refname> 14'git check-ref-format' --branch <branchname-shorthand> 15 16DESCRIPTION 17----------- 18Checks if a given 'refname' is acceptable, and exits with a non-zero 19status if it is not. 20 21A reference is used in Git to specify branches and tags. A 22branch head is stored in the `refs/heads` hierarchy, while 23a tag is stored in the `refs/tags` hierarchy of the ref namespace 24(typically in `$GIT_DIR/refs/heads` and `$GIT_DIR/refs/tags` 25directories or, as entries in file `$GIT_DIR/packed-refs` 26if refs are packed by `git gc`). 27 28Git imposes the following rules on how references are named: 29 30. They can include slash `/` for hierarchical (directory) 31 grouping, but no slash-separated component can begin with a 32 dot `.` or end with the sequence `.lock`. 33 34. They must contain at least one `/`. This enforces the presence of a 35 category like `heads/`, `tags/` etc. but the actual names are not 36 restricted. If the `--allow-onelevel` option is used, this rule 37 is waived. 38 39. They cannot have two consecutive dots `..` anywhere. 40 41. They cannot have ASCII control characters (i.e. bytes whose 42 values are lower than \040, or \177 `DEL`), space, tilde `~`, 43 caret `^`, or colon `:` anywhere. 44 45. They cannot have question-mark `?`, asterisk `*`, or open 46 bracket `[` anywhere. See the `--refspec-pattern` option below for 47 an exception to this rule. 48 49. They cannot begin or end with a slash `/` or contain multiple 50 consecutive slashes (see the `--normalize` option below for an 51 exception to this rule) 52 53. They cannot end with a dot `.`. 54 55. They cannot contain a sequence `@{`. 56 57. They cannot be the single character `@`. 58 59. They cannot contain a `\`. 60 61These rules make it easy for shell script based tools to parse 62reference names, pathname expansion by the shell when a reference name is used 63unquoted (by mistake), and also avoid ambiguities in certain 64reference name expressions (see linkgit:gitrevisions[7]): 65 66. A double-dot `..` is often used as in `ref1..ref2`, and in some 67 contexts this notation means `^ref1 ref2` (i.e. not in 68 `ref1` and in `ref2`). 69 70. A tilde `~` and caret `^` are used to introduce the postfix 71 'nth parent' and 'peel onion' operation. 72 73. A colon `:` is used as in `srcref:dstref` to mean "use srcref\'s 74 value and store it in dstref" in fetch and push operations. 75 It may also be used to select a specific object such as with 76 'git cat-file': "git cat-file blob v1.3.3:refs.c". 77 78. at-open-brace `@{` is used as a notation to access a reflog entry. 79 80With the `--branch` option, the command takes a name and checks if 81it can be used as a valid branch name (e.g. when creating a new 82branch). But be cautious when using the 83previous checkout syntax that may refer to a detached HEAD state. 84The rule `git check-ref-format --branch $name` implements 85may be stricter than what `git check-ref-format refs/heads/$name` 86says (e.g. a dash may appear at the beginning of a ref component, 87but it is explicitly forbidden at the beginning of a branch name). 88When run with `--branch` option in a repository, the input is first 89expanded for the ``previous checkout syntax'' 90`@{-n}`. For example, `@{-1}` is a way to refer the last thing that 91was checked out using "git switch" or "git checkout" operation. 92This option should be 93used by porcelains to accept this syntax anywhere a branch name is 94expected, so they can act as if you typed the branch name. As an 95exception note that, the ``previous checkout operation'' might result 96in a commit object name when the N-th last thing checked out was not 97a branch. 98 99OPTIONS 100------- 101--[no-]allow-onelevel:: 102 Controls whether one-level refnames are accepted (i.e., 103 refnames that do not contain multiple `/`-separated 104 components). The default is `--no-allow-onelevel`. 105 106--refspec-pattern:: 107 Interpret <refname> as a reference name pattern for a refspec 108 (as used with remote repositories). If this option is 109 enabled, <refname> is allowed to contain a single `*` 110 in the refspec (e.g., `foo/bar*/baz` or `foo/bar*baz/` 111 but not `foo/bar*/baz*`). 112 113--normalize:: 114 Normalize 'refname' by removing any leading slash (`/`) 115 characters and collapsing runs of adjacent slashes between 116 name components into a single slash. If the normalized 117 refname is valid then print it to standard output and exit 118 with a status of 0, otherwise exit with a non-zero status. 119 (`--print` is a deprecated way to spell `--normalize`.) 120 121 122EXAMPLES 123-------- 124 125* Print the name of the previous thing checked out: 126+ 127------------ 128$ git check-ref-format --branch @{-1} 129------------ 130 131* Determine the reference name to use for a new branch: 132+ 133------------ 134$ ref=$(git check-ref-format --normalize "refs/heads/$newbranch")|| 135{ echo "we do not like '$newbranch' as a branch name." >&2 ; exit 1 ; } 136------------ 137 138GIT 139--- 140Part of the linkgit:git[1] suite