sub foo {
        my $parameter = $_[0];
        print "\nParameter: $parameter\n";
        $ipaddress = "foo_0";
        $username = "foo_1";
        $password ="foo_2";
        $sessionid = "foo_3";
        $version = "foo_4";
        $returning = ${$parameter};
        return $returning;

}

my $returned = &foo(@ARGV[0]);
print "Returned: $returned\n";