iLAMP

By Vincent Danen, TechRepublic
Friday, February 25 2005 8:21 PM

Linux is a multiuser system, and that means that more than one person can log into the system at any given time. You can also log into the desktop as well as a console (or even two) at the same time.

It's not uncommon to have more than one user connected to a Linux system at one time. Friends or family can connect remotely via ssh.

Determining who has logged into the system is very simple. You can find out by using a couple of small utilities. The easiest to use is the who command, which displays who currently has logged in and from where.

Here's an example:

$ who
root tty1 Jul 24 10:13
joe pts/0 Aug 1 14:17 (somehost.com)

This shows you that root has logged in on the first tty (console). It also shows that joe has logged in via ssh, connecting from the machine "somehost.com." It also indicates the time when these users logged in.

Another useful tool is the last command, which provides information about when a user last connected to the system. Like the who command, the last command returns the username, where they connected, and when they logged in. It also tells you when they logged out or if they're still connected.

Here's an example:

$ last
joe pts/0 somehost.com Sun Aug 1 14:17 still logged in