use strict;
my $str = '00:00-13:59,15:00-23:10,15:00-23:10';
my $regex = qr/((([01]?[0-9]|2[0-3]):[0-5][0-9])|sunrise)-((([01]?[0-9]|2[0-3]):[0-5][0-9])|sunset)(,((([01]?[0-9]|2[0-3]):[0-5][0-9])|sunrise)-((([01]?[0-9]|2[0-3]):[0-5][0-9])|sunset))*/mp;
my $subst = '';
my $result = $str =~ s/$regex/$subst/rg;
print "The result of the substitution is' $result\n";
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Perl, please visit: http://perldoc.perl.org/perlre.html