I just want to protect a folder against myself accidentally changing something in it. The best I've come up with so far is to compress it, which makes a .zip file, then make the zip readonly. Then each time I want to read it uncompress the zip. After I read the files I can trash the uncompressed version and the zip will still be there unchanged. But it would be better if there were a way to change the permission on every file in the directory to readonly in one step.