foreach (<*.in.sep>){ $name = $` if /.in.sep/; open IN, $_ or die $!; open OUT, $name.'.out.sep' or die $!; %hash = map{ s/E99/99/g; $_ => $hash{$_}++;} , ; close IN, OUT; foreach (sort keys %hash){ print "$_ $hash{$_}\n" if !$hash{$_}; } }