How can mod_rewrite be used to route all requests through a single index.php file in the web server root?

When using mod_rewrite to route all requests through a single index.php file in the web server root, you can create a .htaccess file in the root directory with rewrite rules that redirect all requests to index.php. This allows you to handle all requests in a single file and implement custom routing logic within your PHP application. ``` RewriteEngine On RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d RewriteRule ^(.*)$ index.php?url=$1 [QSA,L] ```