#!/usr/bin/perl
use strict;
use warnings;
use Date::Simple 'ymd';

for (my $date=ymd(2008,8,1), my $end=ymd(2008,9,30);$date <= $end; $date++) {
	my $file = $date->format("%y%m%d_name");
	warn("$file: no such file\n"), next unless -e $file;
	open IN, "<", $file or die "Unable to open $file";
	while (<IN>) {
		# ... process
	}
	close IN or die "Unable to close $file";
}