Hi Corion, Thank you !! I set $wwn to 0 and that worked !!. Now I am not getting the error message. Here is the script now:

#!/usr/bin/perl
use warnings;
use strict;
my $wwn = 0;
until ( $wwn eq "q")
{
print "Enter the wwn: ";
chomp ($wwn=<STDIN>);
my @wwn = unpack ("(a2)*", lc($wwn));
@wwn = join (":", @wwn);
print "@wwn\n";  
}
[download]

And here is the output:

C:\Users\Documents\perl\practice>perl wwn.pl
Enter the wwn: 10000000ABCDEFAB
10:00:00:00:ab:cd:ef:ab
Enter the wwn: 10000000C9D2EEFG
10:00:00:00:c9:d2:ee:fg
Enter the wwn: 500604AB12CDEFCD
50:06:04:ab:12:cd:ef:cd
Enter the wwn: q
q

C:\Users\ugrankar\Documents\perl\practice>
[download]

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