Always use the DIRECTORY_SEPARATOR constant when pointing to files/directories on the server-side. It will make your system more portable.
// Do you usually do this? require_once dirname( __FILE__ ) . '/bootstrap.php'; // Or this? Don't! require_once dirname( __FILE__ ) . '\bootstrap.php'; // Do this: require_once dirname( __FILE__ ) . DIRECTORY_SEPARATOR . 'bootstrap.php';
Windows boxes uses backslash as a directory separator while for example Unix uses forward slash. Not using the DIRECTORY_SEPARATOR constant may lead to page-halting errors when for example require() fails locating your file.
Heads up: don’t use it in web URLs 🙂