you should also take a look at WWW::Mechanize and WWW::Mechanize::FormFiller and WWW::Mechanize::Shell just because they make it relatively easy to whip up a script. here's a little script to download router software from Juniper over https.

#!perl
use strict;
use warnings;
$|++;

my $user = '*username-here*';
my $pass = '*password-here*';

my $ver = '6.0';       # lazy version matching
my $ext = 'tgz';       # pdf|tgz documentation

use WWW::Mechanize;
use WWW::Mechanize::FormFiller;
use URI::URL;

my $agent = WWW::Mechanize->new();
my $formfiller = WWW::Mechanize::FormFiller->new();

$agent->env_proxy();

$agent->agent('Mozilla/4.0 (compatible; MSIE 4.01; Windows 98)');

$agent->get('https://www.juniper.net/support/');

$agent->form(2);
$formfiller->add_filler( 'USER' => Fixed => $user );
$formfiller->add_filler( 'PASSWORD' => Fixed => $pass );
$formfiller->fill_form($agent->current_form);
$agent->submit();

$agent->follow(qr(Download software));
$agent->follow(qr(Encrypted));

my @links;
my @all_links = $agent->links();

my @targets = grep {
    m!\Q$ver! and m!\Q//download.juniper.net/!
    } map {$_->[0]} @all_links;

$agent->follow(qr(Software Documentation: Release \Q$ver\E));
@all_links = $agent->links();

push @targets, grep {
    m!\Q-comprehensive-index.pdf! or
    ( m!/download/! and m!$ext$! ) or
    m!/download/rn-sw-\d+\.pdf!
    } map {$_->[0]} @all_links;

# uncomment line below for testing
#  print join $/, @targets, ''; exit;

my $base = $agent->uri;
for my $target (@targets) {
        my $url = URI::URL->new($target,$base);
        $target = $url->path;
        $target =~ s!^(.*/)?([^/]+)$!$2!;
        $url = $url->abs;
        print "mirroring $target$/";
        $agent->mirror($url,$target);
};
[download]