just a dirty hosts refreshing script

hostref.sh

#! /bin/bash

#skip empty or comment lines
function host_filter {
    while read line; do
        echo $line | grep -Ev "^($|#)"
    done
}

#pick second part as hostname
function host_pickname {
    while read entry; do
        echo $entry | awk '{print $2}';
    done
}

#really perform lookup and tidy up
function host_lookup {
    while read name; do
        #for ipv6
        #add=`nslookup -q=aaaa $name | grep AAAA | awk '{print $5}'`
        
        #for ipv4
        add=`nslookup $name | grep "Address" | grep -v "#" | head -n1 | awk '{print $2}'`
        
        echo $add $name
    done
}

host_filter | host_pickname | host_lookup