1. First need to be in monitor mode! Use airmon-ng:
   sudo airmon-ng start wlan0
2. Get the wireless interface name using:
   iwconfig
3. Start getting information on wireless networks for all 5ghz(a), 2.4ghz(b, g) and write it to file. This eg also includes only channel 11:
   sudo airodump-ng wlan0mon --band abg --write test -c 11
   (In this case write and channel are optional. In fact probably better to start with sudo airodump-ng wlan0mon --band abg)