Deleting remote branches?

When I run git branch -a, it prints out like this, f开发者_Go百科or ex:

branch_a
remotes/origin/branch_a

Few questions:

1. What does branch_a indicate?
2. What does remotes/origin/branch_a indicate?
3. How do I delete remotes/origin/branch_a?

1. branch_a indicates that you have a local branch called branch_a.
2. remotes/origin/branch_a indicates that you have a remote called origin, and you are tracking the branch_a within the origin remote. This isn't necessarily associated with your own branch_a, but it probably is (git branch -a doesn't say).
3. Since the remotes/origin/branch_a is a remote tracking branch, it's required if your own branch_a is set up to track the remote. If not, then deleting the origin remote should remove it, or you might be able to simply git branch -d remotes/origin/branch_a.

1. branch_a is the local 'tracking branch' for the remote branch_a.
2. remotes/origin/branch_a is a remote branch, living on the origin repository.
3. git push origin :branch_a removes the remote branch from the origin repository, despite looking a bit hackish. If you want to remove branch_a, run git branch -d branch_a.