История изменений

Исправление Nervous, 23.11.14 00:00 (текущая версия) :

#! /usr/bin/perl

use 5.010;
use strict;
use warnings;
use utf8;
use open qw(:std :utf8);

my $string = <STDIN>;
chomp $string;
my @letters = split //, $string;

my @output;
my %seen;

for my $letter (@letters) {
    if (!defined $seen{$letter}) {
	$seen{$letter}++;
	push @output, $letter;
    } 
}

say @output;

$echo 'Ололо трололо!11расрас ©®™'  |./duplicates.pl 
Оло тр!1ас©®™
$

Исходная версия Nervous, 22.11.14 23:55:

#! /usr/bin/perl

use 5.010;
use strict;
use warnings;
use utf8;
use open qw(:std :utf8);

my $string = <STDIN>;
chomp $string;
my @letters = split //, $string;

my @output;
my %seen;

for my $letter (@letters) {
    if (!defined $seen{$letter}) {
	$seen{$letter}++;
	push @output, $letter;
    } 
}

say @output;