There is also Network Programming With Perl (sample chapters and all code from book: http://modperl.com/perl_networking/), which discusses how to do HUPs and such on Daemons to give them the opportunity to do whatever you need them to do depending on the signals they get. He shows how to write a really nice base class for them which implements Sys::Syslog logging. I really think this book should be on every perl hacker's desk next to the Camel and Conway's OOP.