in reply to Representing windows of time in a string

Strictly speaking, crontab schedules define "points" in time when the specific actions are triggered, whereas it seems you need a broader "range" or "set" of time spans.

It might be overkill, but I think you should be able to accomplish this with the DateTime modules.

For example, take a look at DateTime::Event::ICal... Using the ICal format, you could express your rules as:

my $incident = DateTime->from_epoch( time() ); # your data here my $ok_down = DateTime::Event::ICal->recur( byday=>["su"], byhour=>[ +6, 7] ); unless ( $ok_down->contains( $incident ) { # notify }