Here is the code....

use strict;
use warnings;

open (IN1, "<XOR_portmap.txt") or die;
open (IN2, "<uut_names.txt") or die;
open (IN3, "<nets.txt") or die;
open (IN4, "<enabled_nets.txt") or die;
open (OUT, ">>XOR_portmap_nets.txt") or die;

my @uut_names = <IN2>;
my @nets = <IN3>;
my @enabled_nets = <IN4>;

chomp @uut_names;
chomp @nets;
chomp @enabled_nets;

while (<IN1>) {
    foreach my $i ( 0..$#nets ) {
        print OUT if ((s/m/$uut_names[$i]/) && (s/in1/$nets[$i]/) && (
+s/output/$enabled_nets[$i]/));
    }
}

close (IN1);
close (IN2);
close (IN3);
close (IN4);
close (OUT);
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