301 redirect of tilde account access to a domain

If your adding a domain to an account and the http://www.islandnet.com/~accountname version of your website is in search engine indexes already then you should add a 301 redirect into the root web folder which is usually the /www,  it should read as below but change the mydomainname.com to the domain name you are using. 

RewriteEngine on
RewriteCond %{SERVER_PORT} 80
RewriteCond %{HTTP_HOST} ^(www.)?islandnet.com$
RewriteCond %{REQUEST_URI} ^/~[a-z0-9_-]+((.*))?$ [NC]
RewriteRule .* http://www.mydomainname.com/%2 [R=301,L]