Re: turning off computer

["John M. Rulnick" <rulnick@beaver.wpi.edu>]

   Date: Wed, 5 Mar 1997 18:58:20 -0500 (EST)
   From: I Brake for Moths <rikki@zool46.bio.utk.edu>

   Is there a way for a user without root priveleges to cleanly
   unmount the root file system and shutdown the computer?

Yes, they just need to log in and give the three fingered salute,
after you give them permission.  Here's what you need to know (mostly
from 'man shutdown'): 

       Shutdown can be called from init(8) when the magic keys
       CTRL-ALT-DEL are pressed, by creating an appropriate entry in
       /etc/inittab (already done for you on most debian systems).  To
       prevent this, shutdown can check to see if an authorized user
       is logged in on a virtual console (not an X session, mind
       you). If shutdown is called from init, it checks to see if the
       file /etc/shutdown.allow is present.  It then compares the
       login names in that file with users logged in on a virtual
       console (from /var/run/utmp). Only if one of those authorized
       users or root is logged in, it will proceed. Otherwise it will
       write the message

       shutdown: no authorized users logged in

       to the (physical) system console. The format of /etc/shut-
       down.allow is one user name per line. Empty lines and com- ment
       lines (prefixed by a #) are allowed. Currently there is a limit
       of 32 users in this file.

I hope this helps.  Happy shutdowning.