lpr output filters

[Kemp at DOCKMASTER.NCSC.MIL]

 >> Does it seem reasonalble to try to create an lpr output filter which
 >> selectively prevents certain files from being printed?
 >
 > I would like to "protect" certain files by making them "view only".

No, it is totally unreasonable to do what you ask, unless you

 1) are going to restrict users to ADM-3 terminals with tamperproof
     cables, or
 2) are only interested in saving paper on your printer, not with
     protecting the information in your files.

Consider:

Any user on a serial line could just wire a printer in parallel with the
terminal line.

All micro based terminal emulator programs let you log output to a file.

Output directed to a SunView shell window can be cut and pasted into
another shell or edit window.

The semi-dumb terminal I am typing on now (a Tektronix 4107) has 1500
lines of memory and a printer port.

  (You should get the idea by now).  If the user can see the
information, he can save it, and print it, no matter how clever your
viewer program is.  (If all else fails, he could photograph the screen.)
This should be obvious.

 Dave Kemp <Kemp at dockmaster.ncsc.mil>