rsh and lp

[harrison at utfyzx.UUCP]

The environment: UNIX V.2 on an HP9000/500 (Release 5.11 of HP-UX).  
The users: 1400 undergraduates in a Physics teaching lab.  

The problem: we have our mostly naive users running under rsh(1) for 
their and our protection.  Whenever they send a job to lp(1) they 
get the message:
   sh: /dev/null restricted
The output comes out of the printer (a QMS Postscript PS800+ connected 
to a serial line) but the message is annoying.  

Not knowing where this message comes from, I'll try to be complete about
our configuration below.  I do know it is an artifact of rsh, because
only rsh users get it.

The port /dev/lp has been put to sleep by /etc/rc and then had its 
parameters set with a stty ... < /dev/lp.  Lp(1) is suid to owner 
lp, /dev/lp is mode crw------- and owned by lp, /dev/null is rw by 
the world.  Finally, the driver script in /usr/spool/lp/interface 
has the usual:
	for file in $files
	..
		/usr/local/lib/psf < "$file" 2>&1
	..
line where psf handles Postscript end-of-job stuff (and also converts 
a file not beginning wth "%!" to Postscript). 

Any ideas on how to get rid of this message?
Thanks in advance.
-- 
    David Harrison, Dept. of Physics, Univ. of Toronto
    {ihnp4,utzoo}!utgpu!utfyzx!harrison