1. A portable device, comprising: a power module, configured to provide electric power; a processing module, electrically coupled to the power module and configured to perform an operating system to drive the portable device when being enabled; a sensing module, configured to sense a gesture to generate a set of touch sensing signals when being enabled and to generate an operating system start-up signal when the set of touch sensing signals conforms to a set of preset signals; and an enabling control module, electrically coupled to the sensing module, the power module, and the processing module, configured to conduct a first power path between the power module and the sensing module according to a switching signal to enable the sensing module and to conduct a second power path between the power module and the processing module to enable the processing module when receiving the operating system start-up signal.