For a process that you want to run 24/7 I would suggest you write to a file and have your Perl script read that file. If you don't want to waste the space on the filesystem, you can also write to a named pipe which the Perl script can then read from. This separates the two processes so that they can be handled independently from each other. Important when we are talking about a service that is supposed to run all the time. Finally, if this is something you would be kicking off on the command-line from time to time, you could always use pipes to redirect the output of one into the input of another.
<cmd1> | <cmd2.pl>
