$result = qx(curl -s -b 'auth=$login$md5_password' -F 'file1x=\@$file' '$server');

-b/--cookie <name=string/file> Cookie string or file to read cookies from

$ua->cookie_jar({ file => "cookiefile.txt" });

$ua->cookie_jar( HTTP::Cookies->new() );

  file:            name of the file to restore cookies from and save cookies to
  autosave:        save during destruction (bool)
  ignore_discard:  save even cookies that are requested to be discarded (bool)
  hide_cookie2:    do not add Cookie2 header to requests

$cookie_jar->set_cookie( $version, $key, $val, $path, $domain, $port, $path_spec, $secure, $maxage, $discard, \%rest )

$ua->cookie_jar( HTTP::Cookies->new )

my $cookie_jar = HTTP::Cookies->new();
my $ua = LWP::UserAgent->new;
$cookie_jar->set_cookie(undef, 'auth', $login.$md5_password, '/', $server, undef, 0, 0, 60*60, 0);
my $req = POST $server,
            [file1x => [$file]],
            'Content_Type' => 'form-data';
$cookie_jar->add_cookie_header($req);
my $result = $ua->request($req);
my $return = $result->content;