Rotating logs

Hi,
I am new in here, but have checked all the on-line docs I can find.
I read in the FAQ and elswhere that I can rotate the logs with the
kill -USR1 suid.pid command, and that I should just be able to type:
kill -USR1 'cat pathname/squid.pid'

However this just yields an 'unknown pid' (or similar wording)
errror. I would like to have this in my daily cron, but can't seem to
get it working.

Any help appreciated,

--
Simon Bryan                    simon@olmc.nsw.edu.au
IT Manager                     sbryan@olmc.nsw.edu.au
Information Technology Manager sbryan@mpx.com.au
OLMC Parramatta