marping

marping (Multi-ARp-PING) is a (tiny) command line utility for *nix operating systems used to discover systems in local network and gather their MAC addresses. Discovery is performed by sending ARP (address resolution protocol) requests ("who-has [ip] tell..") and listening to coming answers. However, unlike similar utilities, it's destined to perform rather massive scans very fast. Output to stdout is in "MAC<space>IP" format (by default not found addresses aren't listed).

Examples:

marping 192.168.0.1 192.168.1.1

tries to get MAC addresses of 192.168.0.1 and 192.168.1.1, uses default interface/timeout options (0.6sec)
marping -t 10000 -i br0 -f /etc/hosts

reads file /etc/hosts taking IPv4 addresses, then scans for their MACs using br0 interface and timeout of 1 second