mv /etc/bind/named.conf.local /etc/bind/named.conf.local.orig
find /etc/bind -name "*hosts" | sort -u | grep -vf <(grep zone /etc/bind/named.conf.orig | xargs -n1 | sort -u) | while read file
do
    cat << EOF
zone "$file" {
        type master;
        file "/etc/bind/fastdoublers.com.hosts";
        };
EOF
done >> /etc/bind/named.conf.local