wp-bilty-override

remove_action( 'wp_head', 'wp_shortlink_wp_head', 10, 0 ); // removing the default shortlink
add_action( 'wp_head', 'bilty_shortlink_head'); // adding the new bit.ly shortlink

function bilty_shortlink_head() {
	global $post;
	$shortURL = get_post_meta($post->ID, 'bitlyURL', true);
	if(!empty($shortURL)) {
		echo '<link rel="shortlink" href="'.$shortURL.'" />'."\n";
	} else {
		echo '<link rel="shortlink" href="'.get_bloginfo('url').'?p='.$post->ID.'" />'."\n";
	}
}