in reply to Re: print lines which are not reverse duplicates
in thread print lines which are not reverse duplicates

It seems like we interpreted the question differently. :)

While you replied to the "code", I replied to the "data"

When looking at the OP's code ...

$_ =~ "$comment_author2,$comment_author1"

it seems like the OP wants to exclude lines of the form personA,personA,10 , i.e. 1. and 2. person are equal

But in the description he asked to exclude the first two lines:

personA,personB,10 personB,personA,190

where the relation was reversed.

Cheers Rolf
(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery FootballPerl is like chess, only without the dice