This question already has an answer here:
How can you discover who is connected to a wifi network near you? (you not being connected to it).
I know that some tools can scan your own network, and that some tools like Wireshark can monitor packages (and you can see the MAC addresses of these packages). But what I want to find is a tool that is command-line based for networks where I don't belong.
Is there any simple kismet or nmap command to output this information?