So you know how to ssh into your server. But how do you know if anyone else is shelled into your server?
If more than one person is shelled into a server, and all are trying to fix a problem, it is possible that they could step on each others’ toes. How horrible would it be if two people intending to fix the issue ended up making it worse? It would be grand if the shell provided a simple yet mighty command that displayed all of the users who are shelled in.
As it turns out, Linux does have such a command:
That’s right: simply typing the small and mighty w into your shell and hitting enter will give you a wealth of information on who is doing what on the server at a given time.
root@host [~]# w 18:19:42 up 350 days, 14:14, 1 user, load average: 0.15, 0.05, 0.01 USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT root ttyp0 10.30.6.167 18:19 749days 0.01s 0.00s w
A lot of information is packed into a few lines; let’s unpack it.
- The first line shows what you would see if you ran the uptime command. While uptime is a fast way to find out what the load on a server is, w is even faster.
- The next line lists the information that you’ll see below:
- USER lists the linux user that is logged in
- TTY shows the terminal type that the user is using. It is usually a ttyp#, but could also be a screen.
- FROM is the most useful; it shows either the IP address or the hostname of the user that’s logged in. If you see IPs that are not yours, that most likely means that a support technician is logged in to your server and working on an issue.
- LOGIN@, IDLE, JCPU, and PCPU may not be accurate if you are on a virtual environment. The above example is on a VPS, so it is not accurate.
- WHAT shows the command that that user is currently running. In the above example, I am running w.
If You See Us In Your Server, Please Call Us
When your server is being worked on by one of our Heroic Support Technicians, communication with us can be key. Please call our support line to find out just what is going on, or to let us know what you intend to do. Keeping an open line of communication will help both you and us solve issues faster, and prevent future problems.