Deleting a remote branch works, local pruning does not. why?

On 开发者_StackOverflowmy setup, this seems to work to delete a remote branch:

git push origin :foo

Because when I do it the first time, it's successful, but the second time, it fails because it says the remote branch is not there (as expected). So far so good.

This does not work:

git remote prune origin

It returns with no output, and all my local tracking branches for the deleted remotes are still there.

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By "local tracking branches", do you mean branches you created to track remote branches? git remote prune won't delete those. It'll only delete the remote branches (i.e., it'll delete origin/foo, but not my-local-foo that tracked origin/foo).

You can confirm that origin/foo was deleted by checking the output of

$ git branch -r