To add addon domain via SSH
cpapi2 --user=USERNAME AddonDomain addaddondomain dir=%2Fpublic_html/keerthan.cf newdomain=ADDONDOMAIN.TLD subdomain=NAMEOFSUNDOMAINFORADDON
To Remove addon domain via SSH
cpapi2 --user=username AddonDomain deladdondomain domain=addondomain.com subdomain=addondomain_example.com