how to make a default application open a certain extension file

[sysp]

I know this is possible in GUI gnome.

But is it possible to do it too in shell command??
Let say if i type this in shell:
#file.txt

then it will open gnome-editor in nautilus which open file.txt.


note for other newbie:
gnome is the desktop manager.
nautilus is the explorer windows in gnome.
gnome-editor is one like notepad in MS windows.

thanks

[theKbStockpiler]

Any sort of sophistication is going to be in a shell script anyways is it not? If there is an answer I would guess it would lie in environmental variables. I'm not an expert in this area but I don't think that your question has a market sort of thing. I don't know if bash will do a conditional statement at all but you could only give it one alternative. Your command would have to be an argument would it not?