Some notes on TYPE/CREATOR codes, file extensions, and the association of files to applications on MacOS X. This has been irritating me ever since I switched to OS X.
The main difference from MacOS is that there are now evil wicked file extensions to deal with. A TYPE or CREATOR always overrides a file extension.
The association of file extensions to applications is hidden somewhere,
but you can override it using your
~/Library/Preferences/com.apple.LaunchServices.plist
file. It is fairly clear what this file does.
Read the developer documentation on Launch Services. In particular
file:///Developer/ADC%20Reference%20Library/documentation/Carbon/Conceptual/LaunchServicesConcepts/index.html#//apple_ref/doc/uid/TP30000999