who@ − print list of active users on a host
who@ [ -version [ host ] ]
who@ connects via IP protocol -version (’-4’, ’-6’) to TCP port 11 (Systat) on host and prints any data it receives. It removes CR and converts unprintable characters to a visible format.
If -version is not supplied, who@ uses by default IPv6.
If host is not supplied, who@ connects to the local host.
Some computers respond to port 11 with a list of active users. For example, they may be running
tcpserver -4 0 11 who &
cat(1), delcr(1), tcpclient(1), tcpserver(1)