$ ./test.pl -o outputfile -x xmlfiles -d 'disk1 disk2' -m 'memory1 memory2'
$VAR1 = {
          'm' => [
                   'memory1',
                   'memory2'
                 ],
          'd' => [
                   'disk1',
                   'disk2'
                 ],
          'x' => [
                   'xmlfiles'
                 ],
          'o' => [
                   'outputfile'
                 ]
        };