changeMAC.sh

#!/bin/bash
# Change Wifi interface MAC address on macOS >= 10.10
# Because there are times you want to change your wifi interface's MAC address ;)
# By Sebastien Jeanquier (@securitygen)
# Security Generation - http://www.securitygeneration.com
#
# -------------------------------------------------------------

function usage {
	echo "Description: Set supplied or randomised Airport (Wifi) MAC address on en0."
	echo "Usage: sudo $0 [-r] {MAC address}"
	echo " 	Optional -r: Sets randomised MAC address"
	echo "	Otherwise sets supplied MAC address."
	echo "	MAC address is reset to default upon reboot."
	echo "	Must be run as root."
}

if [[ $# -eq 0 ]] || [ "$1" == "-h" ];
then
	usage "$0";
	exit 1
elif [[ $EUID -ne 0 ]]; then
	echo "[Error] Must be run as root."
	exit 1
else

	# Read flags
	rflag=false
	while getopts r opt
	do
		case "$opt" in
			r)  
				rflag=true
				;;
			\?)		# unknown flag
				usage "$0"
				exit 1
				;;
		esac
	done
	shift "$((OPTIND-1))"

	# Get new MAC address
	if [[ $rflag == true ]]; then
		# Generate random MAC
		newMAC=$(openssl rand -hex 6 | sed 's/\(..\)/\1:/g; s/./0/2; s/.$//')
		randomised=" (random)"
	else
		# Check and use supplied MAC address
		newMAC=$1
	fi

	# Check resulting MAC address is valid
	re="^([0-9A-Fa-f]{2}[:-]){5}([0-9A-Fa-f]{2})$"
	if ! [[ $newMAC =~ $re ]] ; then
   		echo "Error: new MAC address must be in format 00:aa:11:bb:22:cc (case insensitive), you entered: $newMAC" >&2; exit 1
		exit 1
	fi

	# Confirmation
	read -r -p "Are you sure you want to set your MAC address to: $newMAC$randomised? (y/N): " selection
	if [[ "$selection" != "y" ]]; then
		echo "Bailing out!"
		exit 0
	fi

	# Set new MAC address
	# 1) Disable airport interface
	sudo /System/Library/PrivateFrameworks/Apple80211.framework/Resources/airport -z
	# 2) Change MAC addess on en0
	sudo ifconfig en0 ether "$newMAC"
	# 3) Re-enable airport interface
	networksetup -detectnewhardware

	echo "[Done] Set $newMAC on en0."

fi