Send a mail when a post has been updated

functions.php

<?php
function mafs_updated_send_email( $post_id ) {

	// If this is just a revision, don't send the email.
	if ( wp_is_post_revision( $post_id ) )
		return;

	$post_title = get_the_title( $post_id );
	$post_url = get_permalink( $post_id );
	$subject = 'A post has been updated';

	$message = "A post has been updated on your website:\n\n";
	$message .= $post_title . ": " . $post_url;

	// Send email to admin.
	wp_mail( 'user@example.org', $subject, $message );
}
add_action( 'save_post', 'mafs_updated_send_email' );