Script to change your MAC address using macchanger: see http://pacinispace.blogspot.it/2012/01/chance-mac-address-in-sabayongentoo.html

nmac

read -p "Choose the interface: " iface
echo "Which MAC on $iface do you want?"
echo "1 - Set random vendor MAC of the same kind"
echo "2 - Set number1 MAC"
echo "3 - Set number2 MAC"
echo "0 - User defined MAC"
read -p "Do your choice: " choice

systemctl stop NetworkManager

    case $choice in

	[0]* ) 	read -p "Set the MAC XX:XX:XX:XX:XX:XX : " mac
		macchanger --mac=$mac $iface;;
          
        [1]* ) 	macchanger -a $iface;;

        [2]* ) 	macchanger --mac=YY:YY:YY:YY:YY:YY $iface;;

	[3]* )	macchanger --mac=YY:YY:YY:YY:YY:YY $iface;;

	* )	echo "Please do a valid choice";;

    esac

systemctl start NetworkManager