server {
    server_name www.mydomain.com;
    rewrite ^ http://mydomain.com$request_uri? permanent;
}
// end rewrite
server {
server_name mydomain.com;
...
}

## The URL base path to the directory containing the wiki;
## defaults for all runtime URL paths are based off of this.
## For more information on customizing the URLs please see:
## http://www.mediawiki.org/wiki/Manual:Short_URL
$wgScriptPath       = "";
$wgScriptExtension  = ".php";
$wgArticlePath = '/$1';
$wgUsePathInfo = true;

Your mileage may vary but you’d need a similar config as below for nginx.
http://wiki.nginx.org/MediaWiki

        server {
        # rewrite from www.example.com to example.com
        server_name www.gorewiki.com;
        rewrite ^(.*) http://yourwiki.com$1 permanent;
        }

        server {
        server_name www.yourwiki.com;
        root /srv/www/yourwiki.com/public_html;
        index index.php index.html;
        client_max_body_size 5m;
        client_body_timeout 60;

        location / {
         try_files $uri $uri/ @rewrite;
        }

        location @rewrite {
        rewrite ^/(.*)$ /index.php?title=$1&$args;
        }

        location ^~ /maintenance/ {
                return 403;
        }

        location ~ \.php$ {
        include fastcgi_params;
        fastcgi_pass  127.0.0.1:9000;
        fastcgi_index index.php;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        }

        location ~* \.(js|css|png|jpg|jpeg|gif|ico)$ {
                try_files $uri /index.php;
                expires max;
                log_not_found off;
        }

        location = /_.gif {
                expires max;
                empty_gif;
        }

        location ^~ /cache/ {
                deny all;
        }
    }

After restarting nginx all works well with our “pretty” short URL structure on the wiki.