HOWTO: See Who Else Has Been On Your Machine.

We’ve covered off how to see what other users are on your machine right now by using the who command, but how can you see who has been on your machine, but now gone?

Use the last command.

jon@jon:~$ last
jon :0 Thu Mar 30 05:13 still logged in
reboot system boot 2.6.15-19-386 Thu Mar 30 05:13 (00:41)
jon :0 Wed Mar 29 05:29 – 07:10 (01:41)
reboot system boot 2.6.15-19-386 Wed Mar 29 05:28 (01:41)
jon :0 Tue Mar 28 21:54 – 22:24 (00:30)
reboot system boot 2.6.15-19-386 Tue Mar 28 21:54 (00:30)
jon :0 Tue Mar 28 18:29 – 21:14 (02:44)

Using last -d will serve up the same list but with each user’s IP address beside their login name.