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Old 03-18-2013, 01:32 PM   #1
Registered: Jul 2011
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Pls explain the output of who -u command in RHEL 5.6

Hello Friends,

I am running RHEL 5.6.
When I issue the $ who -u command from a non-root user, I get the following output :
san :0 2013-03-18 17:47 ? 4486
san pts/1 2013-03-18 18:43 00:26 6491
san pts/2 2013-03-18 19:44 . 8298 (:0.0)

1. Can someone explain the meaning of ? and
:0 in the 1st line of the output ??
2. With whom the process 4486 is associated,
just as 6491 is associated with pts/1?

Last edited by techie_san778; 03-18-2013 at 01:33 PM.
Old 03-18-2013, 02:10 PM   #2
John VV
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did you read the manual page for "who" ?
man who
Old 03-19-2013, 12:05 AM   #3
Registered: Jul 2011
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Originally Posted by John VV View Post
did you read the manual page for "who" ?
man who
of course, i have. Didn't find the info that i needed.
Old 03-19-2013, 04:16 AM   #4
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who - show who is logged on.

-u, --users : list users logged in
Old 03-20-2013, 03:00 PM   #5
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The ":0" is in the column identifying the terminal. :0 is a GUI login, so there is no real terminal.

The "?" is a null string, usually occurs when the user logs in without a terminal (ssh also does this with commands like "ssh remotehost ls" to take a quick ls of the users home directory on the remote host - no terminal in use...)

The login name "san" appears to be assigned to process 4486...

You can always cross check things by using the ps utility to look at the process list...
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Old 03-21-2013, 07:27 AM   #6
Registered: Jul 2011
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Thanks jpollard !!
That solved my doubt.. Thanks again!!


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