http://www.perlmonks.org?node_id=721755


in reply to Re^2: Remove duplicate lines in a file
in thread Remove duplicate lines in a file

I'm not sure I understand the question. I think you're asking how to print the last entry instead of the first. This code should do that:
use strict; use warnings; my $last_key = undef; my $last_line = <>; #get first line while(<>) { my $key = (split)[0]; if (defined $last_key && $key ne $last_key) { #new key, print the last line from the old key print $last_line; } $last_line = $_; $last_key = $key; } print $last_line; #very last entry won't get printed in the while loop