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I have a Ubuntu 10.04 LTS server.

I'm currently logged in as root, because I suddenly cannot log into my account anymore.

When I execute su useraccount, nothing happens.

The log file auth.log tells me the following:

Jan 25 14:51:43 server su[26174]: Successful su for useraccount by root
Jan 25 14:51:43 serversu[26174]: pam_unix(su:session): session opened for user useraccount by root(uid=0)
Jan 25 14:51:43 serversu[26174]: pam_unix(su:session): session closed for user useraccount
Jan 25 14:51:43 serversu[26174]: + /dev/ttyS0 root:useraccount

So, I can actually log in successfully, but I get kicked out right away.

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up vote 2 down vote accepted

It sounds like your account's default shell has been changed.

Take a look at /etc/passwd. There should be a line similar to this one:


If the last CSV is not your usual default shell, change it.

If your default shell it set correctly, examine the contents of /home/useraccount/.bashrc (or the equivalent of your shell) any every shell script it calls.

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Well, that's the problem then: /bin/false means no shell at all. Ubuntu's default shell is /bin/bash. I have no idea how the shell might have changed. – Dennis Jan 25 '13 at 15:02
That's not the only user where /bin/false is set. Well I will re-setup this server anyway. Maybe it really was caused by the last plesk update. I've got no idea. Thank you. – Peter Jan 25 '13 at 15:03
Glad I could help! /bin/false is correct for non-human users that don't need a shell (e.g., syslog). – Dennis Jan 25 '13 at 15:06

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