matches some dates

date.pl

my $mos = [ 'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec' ];
my $now = localtime;
my ($prev_month, $cur_month, $cur_day) = ($mos->[($now->mon() - 1) % 12], $mos->[$now->mon()], $now->mday());

map { print $out_fh $_ } grep { /(?:$cur_month|(?(?{$cur_day == 1})($prev_month)|$cur_month))\s+(?(1)(?:(?(?<=Feb\s)(?:28|29))30|31)|(?:$cur_day|(??{$cur_day - 1})))\b/ } <$in_fh>;