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