java端通过命令行的操作来获取系统usb数量。也是一个与系统命令交互，实现相应功能的demo，应用与Android平台。-java side through the command line operations to obtain system usb quantity. Also an interaction with the system command to achieve the corresponding functions of the demo, applications an

在linux/mac下 通过命令行工具与串口进行通信，自己验证可以操控tessel2板子，espruino 以及esp32板子等iot开发的设备(A command line tools for developers to communicate with IOT boards(with usb interface))