Re: Q: How to "freeze" LTSP sessions - and unfreeze later.
On Wed, 24 Nov 2004, Finn-Arne Johansen wrote:
> well, you could do it for all the users, something like:
> who | while read WHO WHERE WHEN ; do
> case $WHERE in
> :[0-9]*)
> su -c "DISPLAY=$WHERE xscreensaver-command -lock" $WHO
> ;;
> esac
> done
>
> Replace "xscreensaver-command -lock " with some xlock command, and make
> it loop while you want to have their attention in some way.
Nice. If I understand correctly this locks each screen as the user who is
logged in.
For those who really don't trust their users (though I'm sure you all do)
not to fire up kmines as soon as you start to speak, one could go a little
further.
Suppose you create a dummy "screenlock" user. A teacher runs the
lockdesktops script. This does the following:
- Prompts for a password and sets the screenlock user password to that.
- Locks all student desktops as the screenlock user.
When the teacher is finished demonstrating they announce that the unlock
password is "apples" and the students type that in and get their desktops
back.
This is probably overkill of course and Petter's solution is indeed the
ideal one. It just interested me as an idea. It also might be useful in
an exam situation to enforce adherence to time.
The script would likely have to be setuid "screenlock" or else use sudo.
Gavin
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