lsusb

List USB devices.

Check if USB is 3.0

• http://askubuntu.com/questions/604158/how-do-i-tell-if-a-usb-thumb-drive-is-usb-3-0
• http://superuser.com/questions/527816/usb-2-0-3-0-how-do-you-tell-the-difference

Hardware examination:

• the port and device are usually blue.
• USB 3 has more pins

Software method:

lsusb
lsusb -D /dev/bus/usb/003/023