Refreshing a git clone

[JB Caruth]

Can anybody help me with the git command to refresh (and overwrite) a
previous clone?

> $ git clone  git://git.infradead.org/get_iplayer.git
> fatal: destination path 'get_iplayer' already exists and is not an empty directory.

If I have previously updated the web PVR via the "update software"
link it also gives an error that there are local changes to commit
before I can update.

So how do I just pull the latest out of git and clobber anything local
whether changed or not?

Thanks.