#!/usr/bin/perl

use warnings;
use strict;
until (our $wwn eq "q")
{
print "Enter the wwn: ";
chomp ($wwn=<STDIN>);
my @wwn = unpack ("(a2)*", lc($wwn));
@wwn = join (":", @wwn);
print "@wwn\n";  
}   

##</code><code>##

C:\Users\Documents\perl\practice>perl wwn.pl
Use of uninitialized value $wwn in string eq at wwn.pl line 5.
Enter the wwn: 10000000ABCDEFGH
10:00:00:00:ab:cd:ef:gh
Enter the wwn: 10000000C9A2B3CD
10:00:00:00:c9:a2:b3:cd
Enter the wwn: q
q

C:\Users\Documents\perl\practice>