#!/usr/bin/perl -w 

use strict;

print "please enter the domain name: ";

chomp (my $targetdomain = <STDIN>);

my $file = "named.conf"; # copied to my home folder

rename $file, "$file.bak" or die "Can't rename file '$file': $!\n";

open my $in, '<', "$file.bak" or die "Can't read file '$file': $!\n";
open my $out, '>', $file or die "Can't write file '$file': $!\n";

my $comment = 0;
my $block   = 0;

while(<$in>) {
    if (/^zone\s+"$targetdomain"/) {
        $comment++;
        $block += () = /(\{)/g;
        # print $out '// '.$_;
        next;
    }
    if($comment) {
        $block += () = /(\{)/g;
        s!^!// ! if $comment or $block;
        $block -= () = /(\})/g;
        unless ($block) {
            $comment = 0;
            next;
        }
    }
    print $out $_ unless $comment;
}