Given a date/time as an array of (year, month, day, hour, minute, second), how would you convert it to epoch time, i.e., the number of seconds since 1970-01-01 00:00:00 GMT?
There are many Date manipulation modules on CPAN. My particular favourite is DateTime and you can use the strptime modules to parse dates in arbitrary formats. There are also many DateTime::Format modules on CPAN for handling specialised date formats, but strptime is the most generic.