Check Device Serial Port on Mac

You can find your Arduino via Terminal with

 ls /dev/tty.*

then you can read that serial port using the screen command, like this

screen /dev/tty.[yourSerialPortName] [yourBaudRate]

for example:

screen /dev/tty.usbserial-A6004byf 9600

source: http://stackoverflow.com/questions/12254378/how-to-find-the-serial-port-number-on-mac-os-x