I'm developing onto Arduino platform (ESP8266 with USB -> serial) and sometimes the USB port that is being used stops working and gets frozen. Then I need to plug the device into another USB port. It happens again and once all the USB ports stop working I have to restart the machine which is really annoying. As far as I remember there is a command which is able to restart the USB subsystem individually but I can't remember. How to restart USBs without restarting the entire system? Thanks.

I'm using Mac OS X Sierra.