iw dev wlan0 station dump
This is very useful because it is helpful if you are running something like hostapd and need to see the signal strength and negotiated connection speed.
Station ff:ff:ff:ff:ff:ff (on wlan0)
inactive time: 16309 ms
rx bytes: 25451
rx packets: 325
tx bytes: 44381
tx packets: 159
tx retries: 0
tx failed: 0
signal: -72 [-72] dBm
signal avg: -72 [-72] dBm........
This is especially helpful if you run your own servers. If you are presented with an error message or warning that the signature has changed or does not match the IP/domain you are connecting to you always want to verify manually.
So your e-mail/web client will show you an SHA-1 fingerprint like this:
"Could not verify this certificate because the issuer is unkown" or other reasons such as a mismatch in IP/domain.
It will also show you........