CertiGuide to A+ (A+ 4 Real)  9  Chapter 5: The Linux Operating System       9  Command Line Functions And Administrative Utilities            9  User Management Commands

User Management Commands 1 su - Run a Shell with Substitute User and Group IDs

who is a basic command that shows who is logged in on the system and when they logged in. A typical output from this command is as follows:

phil tty1 Jul 27 22:29

phil pts/0 Jul 27 22:29

usera pts/1 Jul 30 10:21

userb pts/2 Jul 30 23:45

userc pts/3 Jul 30 10:38

An alternative, the w command provides a little more information:

9:49pm up 14 days, 1:05, 5 users, load average: 0.08, 0.06, 0.07

USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT

phil tty1 - 27Jul03 6days 0.34s 0.01s /bin/sh /usr/X1

phil pts/0 - 27Jul03 6days 0.00s ? -

usera pts/1 - Wed10am 1:29m 0.19s 0.19s /bin/bash

userb pts/2 - Wed11pm 1:18m 0.57s 0.57s /bin/bash

userc pts/3 - Wed10am 0.00s 1.30s 0.03s w

This not only shows who is logged on to the system and from where they logged in but also some system information, system load, what each user is doing and when they logged in. This will help the system administrator understand what is system is doing and what resources the various users are using.

User Management Commands 1 su - Run a Shell with Substitute User and Group IDs