require should work, but you might want to check out something like AppConfig for a much more robust and flexible config file system.

require '/tmp/b';
print $x;  # 3
# assuming /tmp/b has   $x=3;   in it
[download]

Update: Actually, above was working for me only w/o 'use strict'.

Wasn't going to mention it originally cause it can be BAD, but you can also read in the whole config file and eval, but as recently discussion in the last week or two, this can be BAD.

Update 2: A quick AppConfig example:

use strict;
use warnings;
use AppConfig;
my $config = AppConfig->new({
            GLOBAL => {
                    DEFAULT  => "<undef>",
                    ARGCOUNT => AppConfig::ARGCOUNT_ONE,
                }
        }, "var1", "var2");
$config->file(\*DATA);
print $config->var1() , "\n";
print $config->var2() , "\n";
__DATA__
var1 = x
var2 = y
[download]