As for Math::BigInt being in the default install, honestly I didn't know that. I've never been able to find a list of what's included by default and from which version on.

If I were to use Math::BigInt, how would I load the value in, as the documentation of the module does not describe loading hexidecimal values, just decimal values.

Finally, as to the point of Math::BigInt living on Cpan, well that only works if you have access to the internet.

This script is being put on number of machines that will be used in demo at a tradeshow, as a tool to use, in case of a problem with the application we are demoing. As such, I am not able to install it myself, but I'm sending the file to someone else, in marketing.

For that reason I must make it as simple as possible, as people in marketing are not what I'd consider "power users." Since I will not be able to see the machines till they are at the tradeshow, and we will not have internet at the tradeshow, this makes cpan preaty much useless.
==
Kwyjibo. A big, dumb, balding North American ape. With no chin.

Here's a Math::BigInt solution.

#!/usr/bin/perl

use strict;
use warnings;

use Math::BigInt;

$_ = "DEADBEEFBABEFACE1234567890";

my $num = Math::BigInt -> new (0);

# Convert the number to a Math::Int decimal number.
while (length) {
    my $chunk = substr $_, 0, 4, "";
    $num *= 2 ** (4 * length $chunk);
    $num  += hex $chunk;
}

# Multiply by 2, add 1.
$num *= 2;
$num += 1;

# Convert the Math::BigInt number to hex.
my @a;
while ($num) {
    push @a => sprintf "%X" => $num % 16;
    $num /= 16;
}
my $new = join "" => @a;

print $new, "\n";
[download]

And here's an Inline::BC solution:

#!/usr/bin/perl

use strict;
use warnings;

use Inline 'BC';

print x("DEADBEEFBABEFACE1234567890");

__DATA__
__BC__
ibase = 16
obase = 10
define x (a) {
    return (a * 2 + 1)
}
[download]

Abigail

Okay, first I need to say, I love your BC solution. It's simple, and elegant. That being said I did some playing around with BigInt, so here's the code I came up with:

sub shift_bs{
    $add = shift;
    $source = shift;
    $num1=Math::BigInt->new("0x".$source);
    $num1->blsft(1);
    $num1+=$add;
    $temp = $num1->as_hex();
    $temp =~ /0x(.*)/;
    return $1;
}
[download]

Yeah, the $add is a legacy thing, but that's okay. I want to thank you especially, because you went to quite a bit of work to come up with that code.
==
Kwyjibo. A big, dumb, balding North American ape. With no chin.