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' <refname> 12'git check-ref-format' --print <refname> 13'git check-ref-format' --branch <branchname-shorthand> 14 15DESCRIPTION 16----------- 17Checks if a given 'refname' is acceptable, and exits with a non-zero 18status if it is not. 19 20A reference is used in git to specify branches and tags. A 21branch head is stored in the `refs/heads` hierarchy, while 22a tag is stored in the `refs/tags` hierarchy of the ref namespace 23(typically in `$GIT_DIR/refs/heads` and `$GIT_DIR/refs/tags` 24directories or, as entries in file `$GIT_DIR/packed-refs` 25if refs are packed by `git gc`). 26 27git imposes the following rules on how references are named: 28 29. They can include slash `/` for hierarchical (directory) 30 grouping, but no slash-separated component can begin with a 31 dot `.`. 32 33. They must contain at least one `/`. This enforces the presence of a 34 category like `heads/`, `tags/` etc. but the actual names are not 35 restricted. 36 37. They cannot have two consecutive dots `..` anywhere. 38 39. They cannot have ASCII control characters (i.e. bytes whose 40 values are lower than \040, or \177 `DEL`), space, tilde `~`, 41 caret `{caret}`, colon `:`, question-mark `?`, asterisk `*`, 42 or open bracket `[` anywhere. 43 44. They cannot end with a slash `/` nor a dot `.`. 45 46. They cannot end with the sequence `.lock`. 47 48. They cannot contain a sequence `@{`. 49 50. They cannot contain a `\`. 51 52These rules make it easy for shell script based tools to parse 53reference names, pathname expansion by the shell when a reference name is used 54unquoted (by mistake), and also avoids ambiguities in certain 55reference name expressions (see linkgit:gitrevisions[7]): 56 57. A double-dot `..` is often used as in `ref1..ref2`, and in some 58 contexts this notation means `{caret}ref1 ref2` (i.e. not in 59 `ref1` and in `ref2`). 60 61. A tilde `~` and caret `{caret}` are used to introduce the postfix 62 'nth parent' and 'peel onion' operation. 63 64. A colon `:` is used as in `srcref:dstref` to mean "use srcref\'s 65 value and store it in dstref" in fetch and push operations. 66 It may also be used to select a specific object such as with 67 'git cat-file': "git cat-file blob v1.3.3:refs.c". 68 69. at-open-brace `@{` is used as a notation to access a reflog entry. 70 71With the `--print` option, if 'refname' is acceptable, it prints the 72canonicalized name of a hypothetical reference with that name. That is, 73it prints 'refname' with any extra `/` characters removed. 74 75With the `--branch` option, it expands the ``previous branch syntax'' 76`@{-n}`. For example, `@{-1}` is a way to refer the last branch you 77were on. This option should be used by porcelains to accept this 78syntax anywhere a branch name is expected, so they can act as if you 79typed the branch name. 80 81EXAMPLES 82-------- 83 84* Print the name of the previous branch: 85+ 86------------ 87$ git check-ref-format --branch @{-1} 88------------ 89 90* Determine the reference name to use for a new branch: 91+ 92------------ 93$ ref=$(git check-ref-format --print "refs/heads/$newbranch") || 94die "we do not like '$newbranch' as a branch name." 95------------ 96 97GIT 98--- 99Part of the linkgit:git[1] suite