uptime
Uptime prints the current time, the length of time the system has been
up, and the average number of jobs in the run queue over the last 1, 5
and 15 minutes. It is, essentially, the first line of a w(1) command.
/proc list of processes
/var/run/utmp
list of active logins
w(1), proc(5), utmp(5)
Heirloom Toolchest 4/17/03 UPTIME(1)