There is a tool called rancid that handles this via expect. The expect man page is actually pretty good and should give you a decent overview of what it can do.

I think the rancid devs use the shell version of expect via a bash script (I haven't looked in quite a while so I'm not sure).

CPAN has a few Expect modules. Rex::Helper::SSH2::Expect looks interesting but I have no experience with it.