[K12OSN] Help with Fl_TeacherTool

Peter Scheie peter at scheie.homedns.org
Fri Apr 27 14:28:56 UTC 2007

Robert Arkiletian wrote:
> I want to make fl-tt better. Is there any way to get a clients
> and
> environment variables if you are root?
> Is XAUTHORITY always =/home/username/.Xauthority  ?

I think so.  Years ago, I wrote a script that we use on our dozens of HP-UX boxen that 
sets XAUTHORITY for root by looking at /home/username/.Xauthority for whoever just su'ed 
to root, and it has always worked flawlessly.  So, I think you'd be safe making that 
assumption.  (We also modified /etc/profile to record each user's $DISPLAY value to 
~/.display so that root could read it and set his own DISPLAY to that same value, so 
that GUI apps over SSH worked properly.)

> Is DISPLAY always =wsXXX.ltsp:0.0  where XXX is the last part of the ip?

Close, maybe close enough: Unless you do something funny in dhcpd.conf and/or the 
/etc/hosts file, that convention should be reliable.  However, I'm not sure the ltsp 
domain part is reliable.  If, during installation, the server's hostname is set to, say, 
fourthgrade.isd234.edu, the clients' DISPLAY may end up wsXXX.isd234.edu.  Or it may 
not; I'm not certain this is a problem, but I seem to recall running into it before (and 
I'm not at an installation that I can verify with ATM).  Even if I'm correct, you 
probably can use an environment variable.  It would be best, however, if people would 
check their setups and report to the list as to whether changing the server's domain 
affects the clients' domain (I hope I'm wrong and this is a non-issue).

The other part to note is that DISPLAY may show just a single 0 rather than a 0.0 after 
the colon (:).

So, what sort of improvement(s) do you have in mind? ;-)


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