nameserverlist.sh

#!/bin/bash

# The file is a newline separated list of domains
# Output is the same list, but with all name servers listed
filename="$1"

while read -r line
do
    name="$line"
    echo -n "$name:"
    output=$(dig +short ns $name)
    for x in $output; do echo -n " $x"; done;
    echo
done < "$filename"