* PARSE_OPT_NOARG: says that this option takes no argument, for CALLBACKs
* PARSE_OPT_NONEG: says that this option cannot be negated
* PARSE_OPT_HIDDEN this option is skipped in the default usage, showed in
* PARSE_OPT_NOARG: says that this option takes no argument, for CALLBACKs
* PARSE_OPT_NONEG: says that this option cannot be negated
* PARSE_OPT_HIDDEN this option is skipped in the default usage, showed in