# Straight forward way (sort keys slows down the larger the list)
my %hash = map { $_ => 1 } @items;
my @uniq = sort keys %hash;

# Using List::MoreUtils::uniq()
use List::MoreUtils qw(uniq);
my @uniq = uniq(@items);

# This is the method under the hood in List::MoreUtils::uniq
my %h;
my @uniq = map { $h{$_}++ == 0 ? $_ : () } @items;