open (IN1, "<common_modify.vhd") or die;
open (IN2, "<nets.txt") or die;
open (IN3, "<enabled_nets.txt") or die;
open (OUT, ">output_file.vhd") or die;
my @nets = <IN2>;
my @enabled_nets = <IN3>;
while (<IN1>) {
	foreach $i (0..$#nets){
	print OUT if (s/\=\>\s+$nets[$i]\,/\=\> 

$enabled_nets[$i]\,/);
	}
}