lpr output filters

[Heather Burris]

In article <1159 at novavax.UUCP> gls at novavax.UUCP (Gary Schaps) writes:
>I would like to "protect" certain files by making them "view only". 

I can understand why you would want to do that, because I have had
occasion to make documents available to students on computer for 
viewing but restricted from printing either because of copyright
problems or, more likely, paper restrictions.  The easiest way
I know to do it is allocate a userid to own the documents (e.g.
userid 'document') and to front-end access to the files with setuid
'document' programs that would allow the access you want.  Therefore
you could provide a script that would allow one to simply list, view
and search the documents and nothing else.  You have to be careful,
though, with standard UNIX programs like 'more' which might allow
a user to slip into vi and then save the output to another file
which could then be printed.

There is no standard protection mode within the UNIX filesystem that
would do what you want, however. 'Read' access allows reading for
any purpose, including printing.

Heather Burris, UCLA