What do you mean "make a file or folder hidden"? Generally, any file or folder name that starts with a dot (.) in *nix is considered a hidden file. At the command line, and ls -a will list all files including hidden ones. So, renaming "file" to ".file" will make it hidden. In GNOME, you can configure whether or not to show hidden files. In a nautilus window (file manager), click Edit > Preferences and check "Show hidden and backup files." I don't know about KDE, but I know you can configure this.
Last edited by jhayden; 08-12-2004 at 10:06 PM.