[howto] gnome's file association

According to this post at http://forums.fedoraforum.org/showthread.php?t=26875 , sereral files affect the file associations.

Though that post targets gnome 2.8, I find that it's still the same for the newest gnome, that is gnome 2.20, after checking these files.

-> /usr/share/applications/defaults.list
This file contains the applications which cause a double-click success. All Mime types will point to a desktop file.

-> /usr/share/applications/[application_name].desktop
This is the file where "defaults.list" will point to. One of the most important things inside this file is the entry "MimeType=".

-> /usr/share/applications/mimeinfo.cache
Contains information in similar form shown for file "defaults.list" in same directory. This file contains ALL associations given to a mime type. There is no need for a specified order of desktop files (see XMMS example lateron)

-> /usr/share/mime (Directory)
This directory contains several information. The sub-directories - excluding packages - contain information about given mime types. You'll see that many mime types already exist.
The packages directory contains the DATABASE calles freedesktop.org.xml!

-> /usr/share/mime/globs
This file contains the file extensions, associated to the mime-types.