Nginx:

location / {
    if (!-e $request_filename) {
        rewrite  ^(.*)$  /index.php/$1  last;
    }
}

Apache:

<IfModule mod_rewrite.c>
  Options +FollowSymlinks -Multiviews
  RewriteEngine On
  RewriteCond %{REQUEST_FILENAME} !-d
  RewriteCond %{REQUEST_FILENAME} !-f
  RewriteRule ^(.*)$ index.php? [L,E=PATH_INFO:$1]
</IfModule>