This has been sitting in my ~/scripts/ folder for the past 3.5 years. Just changing randomly the last pair was enough to do the trick in most situations. Also it requires understanding the first time which one is your WiFi interrface.

  13 Jun  2017 changeMACAddress.sh*

  #!/bin/bash
  sudo ifconfig en0 ether xx:xx:xx:xx:xx:$(od -txC -An -N1 /dev/random|sed 's/ //g'); sudo ifconfig en0 down; sleep 1; sudo ifconfig en0 up