How to programmatically determine whether the Git checkout is a tag and if so, what is the tag name

Question

In a Unix or GNU scripting environment (e.g. a Linux distro, Cygwin, OSX), what is the best way to determine whether the current checkout is a Git tag. If it is a tag, how can I determine the tag name?

One use of this technique would be automatically labeling a release (like svnversion would do with Subversion).

See my related question about programmatically detecting the Git branch.

Answer 1

The solution to your question is to use

git describe --exact-match HEAD 

(which would consider only annotated tags, but you should use annotated and probably even signed tags for tagging releases).

If you want to consider all tags, also lightweight tags (which are usually used for local tagging), you can use --tags option:

git describe --exact-match --tags HEAD 

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But I think you have "XY problem" here, in that you are asking question about possible solution to the problem, rather than asking question about a problem... which can have better solution.

The solution to your problem is to take a look how Git does it in GIT-VERSION-GEN script, and how it uses it in its Makefile.

Answer 2

A better solution (from Greg Hewgill's answer in the other question) would be:

git name-rev --name-only --tags HEAD 

If it returns "undefined" then you are not on a tag. Otherwise it returns the tag name. So a one-liner to do something like my other answer would be:

git_tag=`git name-rev --name-only --tags HEAD | sed 's/^undefined$//'` 

Interactive shell example of how it works:

$ git checkout master Already on "master" $ git name-rev --name-only --tags HEAD undefined $ git checkout some-tag Note: moving to "some-tag" which isnt a local branch If you want to create a new branch from this checkout, you may do so (now or later) by using -b with the checkout command again. Example:   git checkout -b <new_branch_name> HEAD is now at 1234567... Some comment blah blah $ git name-rev --name-only --tags HEAD some-tag