while ($i < 4)
{
        $ID1=`printf "%024x", $i`;
        printf "Value of ID1 = $ID1\n";
        $ID1 = join ' ', unpack("(A2)*",$ID1);
        print "After join command:$ID1\n";
        $i++;
}



bash-3.00# ./genID.pl
Value of ID1 = 000000000000000000000000,
After join command:00 00 00 00 00 00 00 00 00 00 00 00 ,
Value of ID1 = 000000000000000000000001,
After join command:00 00 00 00 00 00 00 00 00 00 00 01 ,
Value of ID1 = 000000000000000000000002,
After join command:00 00 00 00 00 00 00 00 00 00 00 02 ,
Value of ID1 = 000000000000000000000003,
After join command:00 00 00 00 00 00 00 00 00 00 00 03 ,