[K12OSN] unusual shared folder for teachers

Peter Scheie peter at scheie.homedns.org
Sun Nov 22 23:19:34 UTC 2009

To follow up on Terrell's suggestion, see the recipe at 
which describes much the same thing.

As for logging all students off, I wrote this for some teachers a few years ago:

# logoff all the users except the teacher
for x in $(last |grep still |cut -f1 -d" " |uniq)
   if [ "$x" = "$me" ]; then
     pkill -u $x

This was part of a larger script, called by an icon on the teacher's desktop, 
that logged out all students and then shutdown the client machines (but without 
knocking off the teacher who was also on a thin client).  So, you could email 
the above as a file to the teacher along with steps for making it executable, 
how to call it with sudo, making sure the teacher is in an appropriate sudoers 
group, etc (perhaps you could do it yourself if you have ssh access to the 
server, which I'm guessing you don't).  With all that said, I think it would be 
easiest to just tell the teacher to try fl_teachertool.  It's pretty 


Terrell Prude' Jr. wrote:
> Ah, finally an easy one!  :-)  This is how public FTP servers have 
> allowed contributors to upload stuff for 20 years.  What you do is set 
> permissions on that directory (folder) to 730.  Ownership would be by 
> the language arts teacher, and the group ownership would be by 
> "students".  Your students's userID's would all be in this "students" 
> group.  What we're doing here is giving full permissions to "lateacher", 
> but write-only and permissions to group "students".
> The kids can upload all they want.  They can even re-upload over what 
> they just uploaded to you, since the file will be owned by their own 
> userID's (say if they make a last-minute correction and want up upload a 
> newer version).  But they cannot see anything that's in that directory, 
> not even the file they just uploaded.  Furthermore, they cannot clobber 
> any file owned by any other userID; e. g. "student1" cannot mess with a 
> file owned by "student2".
> So, when you're done, it'd look something like this with an "ls -l".
> drwx-wx--- 2 lateacher students 4096 Nov 22 14:13 LA-SharedFolder/
> I did this with a test directory of /LA-SharedFolder.  You can, of 
> course, put this folder anywhere you want, be it under /home, /var, /, 
> or even /Cucamonga if you just want to.  :-)
> --TP
> Daniel Howard wrote:
>> I just set up a 1:1 classroom for an language arts teacher so students 
>> can spend much more time doing their essays, etc. on the PC in class, 
>> start digital portfolios, etc., and one request from the teacher that 
>> came up is to have a shared folder for students to drop copies (and 
>> serve as backup) of their documents, but have it so that students can 
>> drop folders there but cannot read other's work, and in particular not 
>> delete other's work, so permissions have to be set in a new way (for 
>> me at least).  Then, after the teacher edits their work, he wants to 
>> put it back on their desktops.  The teacher has a classroom server 
>> running K12LTSP 5EL (I just couldn't get the old laptops working right 
>> in K12Linux, sadly), and he has about 100 student accounts for his 5 
>> classes.  Any advice?
>> Also, I'm going to train him on how to use fl_teachertool, but won't 
>> get to until after Thanksgiving due to our schedules.  Is there a 
>> simple command he can issue in the meantime from the command line on 
>> his server to log all users off at the end of one class so that 
>> students don't sit down and start doing things on another student's 
>> account (like cyber bullying)?  After a while, students will log in to 
>> get their customized desktops, but for now I want him to have a way to 
>> force things.
>> Any other suggestions for a 1:1 language arts class that would really 
>> show the power of a classroom server-based thin client system?  I have 
>> a highly motivated teacher who considers himself the 'luckiest teacher 
>> in the state' to get this system and a 1:1 in his class.
>> Best, Daniel
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