nginx conf

server {
    listen 80;
    server_name ~^(?!www\.);
    rewrite ^ http://www.$host$request_uri permanent;

}

server {
   listen       80;
   server_name   ~^(www\.)?(?P<domain>.+)$;
    location / {
        root   /var/www/html/$domain;
        index  index.html index.htm;
    }
}