Two built-in MacOS CLI utilities can be used to obtain the currently connected SSID and stored password. airport gets information on currently connected Wi-Fi, security is used to obtain password.
Using these tools I built a CLI in Rust that to quickly share Wi-Fi passwords and connection details, including QR codes that auto-configure iOS and Android devices, but below is how they work individually.
Default MacOS airport utility location:
/System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport.
Sample usage to obtain SSID:
> airport -I | awk '/ SSID/ {print substr($0, index($0, $2))}'
Guest WiFi
security utility can obtain password associated with an SSID (details). Running security provides a login prompt to access keychain, as authentication is required in order to obtain the password.
> security find-generic-password \
-D 'AirPort network password' \
-ga "Guest WiFi" \
2>&1 >/dev/null
password: "HelloFriends!"
The System keychain record for that SSID can be updated so that security is always allowed access to the password. This requires sudo and should only be done for Wi-Fi passwords not considered secret, as will allow this app and others to read the password without being prompted for credentials.
sudo security add-generic-password -U -a <ssid> -D "AirPort network password" -T "/usr/bin/security" -s "AirPort" /Library/Keychains/System.keychain