确定我们是否使用git签出了分支或标签

Question

In a script, I would like to determine if a tag or a branch was checked out.

For now, I have:

git describe --tags

It will show the tag name, but if we are on a branch, it will raise an error (with return status != 0 ):

fatal: No names found, cannot describe anything.

Can I rely on this behavior or is there a better/more official way to do so?

Are there some cases that are not caught by this method that I should know?

Answer 1

You can use git symbolic-ref HEAD to check if you are on a branch and get its name:

> git checkout master
[....]
> git symbolic-ref HEAD
refs/heads/master
> echo $?
0

If you have checked out a tag you will get an error:

> git checkout some_tag
[....]
> git symbolic-ref HEAD
fatal: ref HEAD is not a symbolic ref
> echo $?
128

Answer 2

(edit) better than what I had earlier:

if read what where huh; test "$what" = ref:
then echo On branch ${where#refs/heads/}
else echo "not on any branch; last checkout was:"
     git reflog|sed '/checkout:/!d;q'
fi < "`git rev-parse --git-dir`"/HEAD

will tell you where your last checkout came from.

git log HEAD^! --oneline --decorate

will tell you all the symbolic names for your current commit.

Answer 3

git status (or git branch ) to know on which branch you are. Note: you're always on a branch: the default branch is master .

Use git tag to know the list of tags on the current branch.

Answer 4

Well after some testing around, it turns out git describe --tags wasn't very reliable (in one case I had checked out a branch it did return something).

I ended up using:

git branch | grep '^*'

This will return the selected branch. In case I checked out a tag, this will return:

* (no branch)

In my script I parse the string to check if it contains (no branch) .