Perl [ hash - Single sample ]

Assuming you have a sample with a column that presenter replications.
you to remove repetitions and maintain a single sample!
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#!/usr/bin/perl
use strict;
use warnings;


various boot
=cut   # commeted 
my %hash;
$hash{1}='hard';
$hash{1}='soft';
$hash{1}='hard';
$hash{1}='soft';
$hash{2}='perl';
$hash{2}='linux';
$hash{2}='perl';$hash{2}='linux';
=cut



my %hash=('hard'=>'1',
        'soft'=>'2',
        'hard'=>'3',
        'soft'=>'4',
        'perl'=>'5',
        'linux'=>'6',
        'perl'=>'7',
        'linux'=>'8');


my %hashTmp;
foreach my $key (keys %hash){
    if(exists $hashTmp{$key}){
        next;
    }else{
        $hashTmp{$key} = $hash{$key};
        print "single sample - $key\n";
    }
}


$perl command_line.pl

single sample - perl
single sample - soft
single sample - linux
single sample - hard