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Old 03-19-2014, 02:21 AM   #1
sryzdn
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A question on last command


Hi,

I am testing "last" and "who" commands on my own PC. Apart from me, who is the only user and the reboots, I can see "unknown" users in what "last" produces:

Quote:
(unknown :0 :0 Tue Jan 21 18:24 - 18:26 (00:02)
what does it mean?
 
Old 03-19-2014, 03:21 AM   #2
kooru
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are you using Fedora?
 
Old 03-19-2014, 03:22 AM   #3
sryzdn
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Quote:
Originally Posted by kooru View Post
are you using Fedora?
yes
 
Old 03-19-2014, 03:28 AM   #4
kooru
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Then probably: https://bugzilla.redhat.com/show_bug.cgi?id=760834
 
Old 03-19-2014, 04:03 AM   #5
sryzdn
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Quote:
Originally Posted by kooru View Post
yes I saw that too. But the "who" command returns normally, the "last" is giving me such messages.
 
Old 03-19-2014, 04:39 AM   #6
kooru
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because "who" does see users logged now.

Code:
unknown :0 :0 Tue Jan 21 18:24 - 18:26 (00:02)
unknown is 21 Jan, so you can see it just with "last" command

Try to reproduce the bug and use who command.
 
Old 03-19-2014, 04:51 AM   #7
sryzdn
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actually, I can see many "unknown" when I execute "last", I just mentioned one of them in my post here.

Last edited by sryzdn; 03-19-2014 at 04:59 AM.
 
Old 03-19-2014, 05:06 AM   #8
kooru
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man last
man who

when you reproduce the bug, and use who, you'll see it.

Last edited by kooru; 03-19-2014 at 05:07 AM.
 
Old 03-19-2014, 06:49 PM   #9
jpollard
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It isn't really a bug.

When one of the xdm/kdm/gdm/... session managers start they allocate a terminal (first unused terminal, which can be tty1). To record the fact that it is in use the xdm/kdm/gdm register it as in use by gdm for the purpose of running X (the :0 entry).

You get multiple entries when you use the "user switch" option of a screen lock, which directs the xdm/kdm/gdm/... session manager to start a new X server, and allocate a new terminal.

The "unknown" is put in the user field of the utmp entry because until a user logs in, it is unknown as to what user it will be.

As a last thing that can cause confusion... if a graceful shutdown is not done (or the user aborts the X server for some reason) the "unknown" can remain behind as an incomplete record, showing additional "unknown" entries.

Last edited by jpollard; 03-19-2014 at 06:51 PM.
 
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