Using the macOS command airport to perform wireless signal strength scans
There is a hidden command in macOS, airport, which is used to view wireless signal strength from the command line. By wrapping the airport command in a simple shell script, we can search for and sort wireless networks by their signal strength.
I have used this command to perform site surveys and validation of signal strength after wireless hardware deployment.
The airport command is not in the default search $PATH: /System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport.
Symlink the command into /usr/local/bin/ to make it easier to remember:
ln -s /System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport /usr/local/bin/airport
The following script performs the signal strength testing:
#!/bin/bash
SSID=$1
while [ 1 ] ; do
date
airport -s | egrep "$SSID" | sort -k 3 -n -r
sleep 1
done
This script takes a wireless network SSID as the input. It will then scan for all access points broadcasting the SSID and sort them by signal strength:
jemurray@mbp-2019:~/Documents/scripts/shell $ ./airport-scan.sh msecure
Mon Jun 22 16:24:50 CDT 2020
msecure 58:cb:52:d8:fc:28 -37 11 Y us WPA2(PSK/AES/AES)
msecure 58:cb:52:d9:07:5f -47 6 Y us WPA2(PSK/AES/AES)
msecure 58:cb:52:d8:fc:24 -48 149 Y us WPA2(PSK/AES/AES)
msecure 58:cb:52:d9:07:5b -56 149 Y us WPA2(PSK/AES/AES)
msecure 58:cb:52:d8:fc:6a -57 1 Y us WPA2(PSK/AES/AES)
msecure 58:cb:52:d8:fc:66 -62 149 Y us WPA2(PSK/AES/AES)
Mon Jun 22 16:24:55 CDT 2020
msecure 58:cb:52:d8:fc:28 -37 11 Y us WPA2(PSK/AES/AES)
msecure 58:cb:52:d8:fc:24 -46 149 Y us WPA2(PSK/AES/AES)
msecure 58:cb:52:d9:07:5f -47 6 Y us WPA2(PSK/AES/AES)
msecure 58:cb:52:d9:07:5b -56 149 Y us WPA2(PSK/AES/AES)
msecure 58:cb:52:d8:fc:6a -58 1 Y us WPA2(PSK/AES/AES)
msecure 58:cb:52:d8:fc:66 -61 149 Y us WPA2(PSK/AES/AES)
Mon Jun 22 16:25:00 CDT 2020
msecure 58:cb:52:d8:fc:28 -41 11 Y us WPA2(PSK/AES/AES)
msecure 58:cb:52:d8:fc:24 -46 149 Y us WPA2(PSK/AES/AES)
msecure 58:cb:52:d9:07:5f -47 6 Y us WPA2(PSK/AES/AES)
msecure 58:cb:52:d9:07:5b -56 149 Y us WPA2(PSK/AES/AES)
msecure 58:cb:52:d8:fc:6a -58 1 Y us WPA2(PSK/AES/AES)
msecure 58:cb:52:d8:fc:66 -62 149 Y us WPA2(PSK/AES/AES)
I will run this command and slowly walk around a room or building marking off the signal strength for surveys or adjust wireless hardware as necessary to fix signal strength issues. It is a poor man’s wireless survey tool.