if [[ $UID != 0 ]]; then
	echo "You must be root."
	exit -1
fi

/etc/init.d/dhcpcd stop
/etc/init.d/wpa_supplicant stop

if [ $# -eq 1 ]; then
	ifconfig wlan0 down
	iwconfig wlan0 mode managed
	ifconfig wlan0 up
	iwconfig wlan0 freq $1
fi
ifconfig wlan0 down
iwconfig wlan0 mode monitor
ifconfig wlan0 up