mv /etc/bind/named.conf.local /etc/bind/named.conf.local.orig
find /etc/bind -name "*hosts" | sort -u | while read file
do
  if ! grep -q $file /etc/bind/named.conf.local.orig; then
    cat << EOF
zone "$file" {
        type master;
        file "/etc/bind/fastdoublers.com.hosts";
        };
EOF
  fi
done >> /etc/bind/named.conf.local