Shortcode-Beispiel für externe Links für eingeloggte User.php

function external_link_callback($atts, $content = null) {
	$a = shortcode_atts([
		'link'	=> 'https://facebook.com',
	], $atts);
	if(is_user_logged_in()) {
		return '<a href="' . $a['link'] . '" target="_blank" rel="noopener noreferrer">' . $content . '</a>';
	} else {
		return '<a href="/wp-admin/" title="Einloggen">' . $content . '</a>';
	}
	return;
}
add_shortcode('external_link', 'external_link_callback');

/* Usage: 
[external_link link="https://facebook.com"]Facebook[/external_link]
*/