for domain in `cat domains.txt`; do ip=`host $domain|grep address|awk '{print $4}'`;echo $domain=$ip; done;
The only thing you need to change is domains.txt if your filename is different which is expected to just be a list of all the domains/hostnames you want to find the IPof.
The script will echo the list like this:
domain.com=1.2.3.4........