Perl for Sysadmins, ISBN 9781565926097 and Minimal Perl: For UNIX and Linux People, ISBN 1932394508 are worth picking up. Quite a few of the online tutorials give some awful advice which may, sometimes, get the job done but will cripple your growth and enjoyment of Perl. Ask questions here often and you'll get, usually, good advice from all kinds of perspectives and areas of expertise.