The FreeBSD Diary
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uptime, w, and who show nobody logged in 2 November 2000
I was working on a box for a client. They asked me to help.
After fixing the problem, I checked to see if the client was still logged in.
Here's what I saw:
[root@p100:/var/log] # who [root@p100:/var/log] # w 9:21PM up 5:18, 0 users, load averages: 0.08, 0.09, 0.03 USER TTY FROM LOGIN@ IDLE WHAT
That's wrong. You can't issue a who or a w and get no users. You're logged in. You should at least see you. uptime gave similar incorrect information.
Actually, you can be logged in and not seen. Here are the various things people have mentioned:
My first thought was: someone has root'd this box.
So I asked on IRC and was told that it seems that my /var/log/wtmp is screwed. DOH!
So I logged out and back in again. Then everything worked:
[root@p100:/var/mail] # who dan ttyp1 Nov 1 21:24 (22.214.171.124) [root@p100:/var/mail] # uptime 9:50PM up 5:47, 1 user, load averages: 0.00, 0.01, 0.00
|The explanation is easy. The problem I was fixing was a full /var filesystem. That meant the contents of /var/log/wtmp was incorrect. It's updated each time someone logs in. By logging out and back in again, that file was updated correctly.|