--force, -f Used to force to install or force to renew a cert immediately.
--staging, --test Use staging server, just for test.
--debug Output debug info.
--output-insecure Output all the sensitive messages. By default all the credentials/sensitive messages are hidden from the output/debug/log for secure.
--webroot, -w /path/to/webroot Specifies the web root folder for web root mode.
--standalone Use standalone mode.
--stateless Use stateless mode, see: $_STATELESS_WIKI