Как сделать redirect/rewrite в nginx?

# trying redirects from http://   www.site.com to http://   site.com
if ($host = "www.site.com") {
rewrite ^ $scheme://site.com$uri permanent;
}

...

location / {
    try_files $uri $uri/ @modx-rewrite /index.php?/$request_uri;
    location ~ .php$ {
    fastcgi_pass unix:/var/run/php5-fpm.sock;
    fastcgi_index index.php;
    fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
    include fastcgi_params;
    }

rewrite ^ http://$http_host$request_uri? permanent;

location / {
    rewrite ^ http://$http_host$request_uri? permanent;
     ...
    }