su questions

[Johann Spies <jspies@sun.ac.za>]

Consider the following:

First question:
-----------------------------
root@bywoner:~# su - js
/dev/tty1: Operation not permitted
14:46:30 js@bywoner:~$

Why the /dev/tty1-message?
------------------------------

Second:
----------------------
root@bywoner:~# su - remstats
root@bywoner:~# whoami
root
root@bywoner:~# su - postgres
postgres@bywoner:~$ whoami
postgres
postgres@bywoner:~$
postgres@bywoner:~$ grep postgres /etc/passwd
postgres:x:31:32:postgres:/var/lib/postgres:/bin/sh
postgres@bywoner:~$ grep remstats /etc/passwd
remstats:x:105:105::/var/lib/remstats:/bin/false

Why wouldn't 'su - remstats' make the user remstats while 'su - postgres'
works as expected?

BTW changing remstats' shell in the /etc/passwd to /bin/sh does not
make any difference in this behaviour.

Regards.
Johann
-- 
Johann Spies          Telefoon: 021-808 4036
Informasietegnologie, Universiteit van Stellenbosch

     "Praying always with all prayer and supplication in the
      Spirit, and watching thereunto with all perseverance 
      and supplication for all saints."       Ephesians 6:18