I want www.mysite.example to go to mysite.example as normal in .htaccess for SEO and other reasons.

My /etc/nginx/sites-available/www.example.com.vhost config:

server {
       listen 80;
       server_name www.example.com example.com;
       root /var/www/www.example.com/web;

       if ($http_host != "www.example.com") {
                 rewrite ^ http://example.com$request_uri permanent;
       }

I have also tried

server {
       listen 80;
       server_name example.com;
       root /var/www/www.example.com/web;

       if ($http_host != "www.example.com") {
                 rewrite ^ http://example.com$request_uri permanent;
       }

I also tried. Both the second attempts give redirect loop errors.

if ($host = 'www.example.com' ) {
rewrite ^ http://example.com$uri permanent;
}

My DNS is setup as standard:

site.example 192.192.6.8 A type at 300 seconds
www.site.example 192.192.6.8 A type at 300 seconds

(example IPs and folders have been used for examples and to help people in future). I use Ubuntu 11.