Still learning on my end.
I am reviewing the code and am trying to understand this:

$cnter{$_}{$title}++ for @line;

I see this as a hash, %cnter, being populated . $_ is the word and the $title is the section. I see that the keys = $_ in this loop which are all the words. The value would then be the $title and the ++ is to count each individual word appearing in the section. Is the 'for @line' portion used for reading each line as it comes through?

I think this means this code already has a hash of all the words in each section: keys %cnter. I am tryin to figure out how to detemrine how to identify the hash for each section.

Thanks-