Hi, I'm trying to add a word to the end of a permalink but I can't seem to get this right. Right now, the "-arbitrary-word" is not appear directly after the permalink. Basically, I'm linking the featured image to a page with the same URL + "-pdf". There's probably a cleaner way of doing this but I can't find a way.
echo '<a href="' . $permalink = get_permalink($post->ID) . '-pdf' . '"> the_post_thumbnail() echo </a>