in reply to Get unique fields from file
Assuming your Perl is at least semi-modern, you can do
use List::Util 'uniq'; my @uniqueOutput = uniq( @output );
List::Util has been in Perl since Perl version 5.7.3, and uniq() has been in List::Util since List::Util 1.45. There are also variants (uniqnum(), etc) should they be more appropriate to your use.