And to go back a bit to one of the original questions; the prefix-with-a-dot method hides a file from "normal" directory listings (although there is a flag to show them, just as "hidden" files can be seen via some clicking), but in general on a *nix system a program will have the same filesystem privileges as the person who runs the program, so if your program wants to be able to edit a file the user has to also be able to edit that file. Making the structure of the file opaque can't prevent a user from corrupting the file, but at least it's possible that the edit they make will just corrupt the file rather than change it to something valid-but-different.