#!/usr/bin/perl 

use Tie::CaseInsensitive;
tie %HASH, 'Tie::CaseInsensitive';

$HASH{BoB}  = 1; 
$HASH{bob}  = 2;
$HASH{BOb}  = 3;   

print "Here are all the key value pairs\n";
foreach(keys %HASH){
   print "$_,$HASH{$_}\n";
}