How to tell which commit a tag points to in Git?

Question

I have a bunch of unannotated tags in the repository and I want to work out which commit they point to. Is there a command that that will just list the tags and their commit SHAs? Checking out the tag and looking at the HEAD seems a bit too laborious to me.

Update

I realized after I went through the responses that what I actually wanted was to simply look at the history leading up to the tag, for which git log <tagname> is sufficient.

The answer that is marked as answer is useful for getting a list of tags and their commits, which is what I asked. With a bit of shell hackery I'm sure it's possible to transform those into SHA+Commit message.

Answer 1

One way to do this would be with git rev-list. The following will output the commit to which a tag points:

$ git rev-list -n 1 $TAG

You could add it as an alias in ~/.gitconfig if you use it a lot:

[alias]
  tagcommit = rev-list -n 1

And then call it with:

$ git tagcommit $TAG

Possible pitfall: if you have a local checkout or a branch of the same tag name, this solution might get you "warning: refname 'myTag' is ambiguous". In that case, try increasing specificity, e.g.:

$ git rev-list -n 1 tags/$TAG