🚀 go-pugleaf

There are a couple of public domain utilities that will do what you want.
If you have access thru Compuserve, via a local users group, whatever, 
you should be able to find them.  The two I have are ALTER, which only
does a single file, and CHMOD that can do several files at once.  I use
it like a security system - creating subdirectories with funny names, then
hiding them.  Actually, you can also "zap the bits" with a disk utility
such as Norton - I often do this (although I use Media Magician since Norton
didn't [initially] support my 15M hard disk).

"You know, the more you know, the more you realize you don't know" Bela Lubkin