This Linux utility will add colors to the visible cloaks in NWN data files (assuming your game is patched to at least 1.68). Like Cloak Converter for Windows, it will work on saved games, modules, character files, etc., and it will automatically create backups. This version requires GTK+ to be installed (which I believe should be the case for Gnome desktops, and would be the case if you already have, for example, GIMP installed).
Currently, it is known that this utility will not work on database files (because they have a different format than other NWN files) and Premium Modules (because they are encrypted).
Players may find this useful for updating saved games, older modules, and character files in your local vault. If your saved game or module uses an old hakpak that overrides baseitems.2da, then you may lose the colors the next time you load your file. If this happens, you'll need to get an updated version of the hakpak. (If you use Wine, then Cloak Hakker should be able to help with the hak paks.)
If there is something missing, or you encounter a bug, let me know. And sorry for the delay in getting out a native Linux version.