How to scan broadcasting networks

[tophmey]

I'm hacking a script that will run on an ZenWifi ET8 running in AP mode.
I want it to perform a wireless scan to see if a particular network is available, it doesn't need to join the network or anything, just check to see if it is broadcasting.

I'm currently using

wl -i eth4 radio on
wl -i eth4 scan ssid="ThisSsId"
wl -i eth4 scanresults
wl -i eth4 radio off

And also considering

wl ap 0
wl scan --ssid="ThisSsId"
wl scanresults
wl ap 1

It seems to work well enough, but I don't know much about the side effects of either of these. For example, I notice that they sometimes generate errors or unexpected messages in my logs:

kernel: CFG80211-ERROR) wl_cfg80211_event : Event handler is not created

Or

kernel: CSIMON: CSIMON[1.1.0] Initialization
kernel: CSIMON: M2M usr already registered ...

I've also tried horst, but I don't understand enough about the interfaces, devices, monitoring mode, and who knows what else.

Does anyone have any helpful considerations or suggested readings? Or suggestions for other commands that might be simpler?

I've been trying to dig into the Site Survey code, but I've yet to find anything more user friendly than the "wl" command.

Thanks for any help you can offer.