This command allows use to view who is logged on either interactively at the console or via an SSH session. The who command without parameters gives us the basics.

[root@esx1host firewall]# who
root tty1 Jul 25 10:30
root tty2 Jul 25 09:56
root pts/1 Jul 29 09:29 (workstation.domain.com)

If we want to see all the details of users we can use the -a switch to show all data. We tend to combine -a with -H (i.e. -aH) to display column headers making it easier to read and interpret.

[root@host root]# who -aH

Posted in Linux/Unix