This Perl module is useful for writers of daemons and other processes
that need to tell whether they are already running, in order to
prevent multiple process instances. The module accomplishes this
via *nix-style pidfiles, which are files that store a process
identifier.

Inspired by Proc::PID_File, but with a much simpler interface.

WWW: http://search.cpan.org/dist/Proc-PID-File/