#!/usr/local/perl5.006/bin/perl -w

use strict;
my $var = shift;

print "var: $var\n";
my $temp = sprintf "%lx", $var;
print "temp: $temp\n";
my $packed = pack "H*", $temp;

print "packed: $packed\n";

$temp = unpack "H*", $packed;
print "temp: $temp\n";
my $unpacked = hex $temp;

print "unpacked: $unpacked\n";

##</code><code>##

>pack.pl 12
var: 12
temp: c
packed: À
temp: c0
unpacked: 192
>

##</code><code>##

16^0 <= x < 16^1 (# of hex digits is odd)  bad
16^1 <= x < 16^2 (# of hex digits is even) good
16^2 <= x < 16^3 (# of hex digits is odd)  bad
16^3 <= x < 16^4 (# of hex digits is even) good
...