Using nmap to find network devices (IP, MAC) in your LAN

If someday you plug a device which does not have a display (something like a monitor) into your LAN network and don't know where it is on the network (IP address), E.g my Beaglebone Black, you can use nmap. Nmap is a free network scanner utility.

$ sudo nmap -sn

(scan the network, my LAN network, to find the device)

The results are something like:

I can see one Texas Instruments device which is my Beaglebone Black's network chip manufacturer. So, that is my board.