#!/usr/bin/perl

use strict;
use warnings;

my $fh;
open($fh, "dig -t AXFR \@127.0.0.1 private.invalid. |")
    || die "Can't open dig: $!";

while (<$fh>) {
    if (/^(\S+)._vhosts.private.invalid.\s+\d+\s+IN\s+TXT\s+\"(.+)\"$/) {
	print $1, ". master: ", $2, "\n";
    }
}