Copy sub-domain names in a single file (one name per line) for example, create a file /root/subdomain and add sub-domains
abc
xyz
qaz
wsx
Save the file and execute the following script
for i in `cat /root/subdomains`; do echo "$i IN A xx.xx.xx.xx" >> /var/named/yourdomain.tld.db; done;
where,
xx.xx.xx.xx is the IP you want to point the sub-domains to.
yourdomain.tld is the domain on which you want to set the sub-domains.
Don't forget to restart the 'named' service.
