"What does 'mv' do?"

Just so James won't go behind my back telling stories about my cluelessness to everyone and their mother:

Yes, I did ask him what the mv command does.

...

Finished laughing? Good. The story is fairly simple, actually. James had downloaded his ~10800 emails that had accumulated over the course of a few days, and was feeding them to his gnus, so that all mail would end up in the right mailbox. This involved a command like mv -iv ~/xar .emacs-something-obscure, and then switching back to gnus to process the thing. Of course I know what mv does; what I really wanted to ask was what the point of those commands was—why the hell he kept copying (well, moving) files over that one obscure file.

But yeah, brain fart. Ignore me.