Automatic Facebook URL Linter…

I am trying to come up with a way to automatically “lint” a post each time it is viewed: here is what I have tried putting in my post but it doesn’t seem to be working…

<?php
function lintUrlToFacebook(){
$theUrl = escapeshellarg("<?php echo get_permalink(); ?>");
$command = "curl https://developers.facebook.com/tools/lint/?url=".$theUrl."&format=json";
exec($command);
}?>

anyone have any ideas on how this could be acomplished on a per page/post basis?