if hacker really only wants the breaks only on vowels, it is an easy change. (if ($prefix =~ /[aeiou]$/ and $prefix ne $section) { ...?). but it begs the question, what is the first anchor? no anchors at all until you encounter a vowel in the second position? i was hoping to provide a hint to the right direction (substr), without providing a complete solution, because there are a lot of unknowns here!

the only issue with buffering versus printing is if you want to print the navigational anchor links before the content, without assuming that every anchor will actually exist. it may be best to first determine which anchors will actually be present, then print the navigational links, then the content.