USERS(1) BSD Reference Manual USERS(1)
users - list current users
users
users lists the login names of the users currently on the system, in sorted order, space separated, on a single line.
/var/run/utmp
finger(1), last(1), who(1), utmp(5)
The users command appeared in 3.0BSD. MirBSD #10-current June 6, 1993 1