$line = "On January 1 1970 the unix epoch commenced.";
my @months = qw(
                Jan
                Feb
                Mar
                Apr
                May
                Jun
                Jul
                Aug
                Sep
                Oct
                Nov
                Dec
                );
my $months = join "|", @months;
my ($month, $day, $year) = $line =~ m/((?:$months)\w+)\s+(\d+)\s+(\d+)/i;
print "month\t$month\nday \t$day\nyear\t$year\n";