On BSD systems you can press ^T for SIGINFO and that prints some progress information, at least for tools like dd and cp, not sure about cat and I don't have a BSD system to test. Linux doesn't have this unfortunately. GNU tools often support it (when run on BSD), it's just that the kernel doesn't.

On Linux you can do a 'kill -USR1 $(pidof dd)' to have dd print a progress report.