How do you change the default opening application?

[Derek Broughton]

Tony Baldwin wrote:

> marc wrote:
> 
>>>>> Right click and select Properties|Open With|Add
>>>>> You can then add the application if it's not already there. Select
>>>>> 'Use Custom Command to put in the path of the app if it's not listed
>>>>> in your applications.
>>>> Yes, tes, I know, but this isn't what I'm asking.
>>>>
>>> Well you've got me there... Just what _are_ you asking then?
>> 
>> To change the default app when a filetype/mimetype doesn't exist. When
>> the system has no idea what the file is.
>> 
> 
> Do YOU know what kind of file it is?
> Without that little tidbit, we can't tell you what application to use to
> open it.
> What is the file extension?

.chm - he did tell us that.

I know how to do this in KDE, but not Gnome.
-- 
derek