'who' output is blank, returns nothing

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Environment

SUSE Linux Enterprise Server 9

SUSE Linux Enterprise Server 10

SUSE Linux Enterprise Server 11

Situation

Typing in 'who' at the command prompt returns to a blank prompt.

Typing in 'who --all' returns more info, but does not list users currently logged in.

ssh logins take up to 30 seconds to complete.

Resolution

/usr/bin/who uses the /var/run/utmp file to store information. That file needs to have these attributes:

#ll /var/run/utmp

-rw-rw-r-- root tty .... /var/run/utmp

In this case, it was observed that the 'rw' attributes were not there for both the user (root) and group (tty), just 'r'.

To fix:

1. chmod 664 /var/run/utmp

If that doesn't fix it:

1. mv /var/run/utmp /var/run/utmp.old (rename the file)

2. touch /var/run/utmp (create a new file)

3. chown root:tty /var/run/utmp (set the user and group correctly)

4. chmod 664 /var/run/utmp (set the file attributes correctly)

Now users logging in to the console or ssh should be able to use the 'who' command and have the names show up in the list.

Disclaimer

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