How do I set meld as the default diff viewer for ubuntu updates?

[Daevid Vincent]

I am coming from Gentoo, where there was an excellent tool "etc-update"
and you could define your diff tool to be anything you wanted. So as you
went through each updated /etc file (after an 'emerge world' for
example), it would load the new /etc file and your existing one into
this amazing graphical diff tool called
'meld' ( http://meld.sourceforge.net/ ). You'd make your changes, save
and exit, then move on to the next /etc/ file to be investigated... All
nice and automatic like.

In Ubuntu, I'm a little concerned that something like this doesn't
exist?? 
When I do updates, I'm given a rather useless menu IMHO that says things
like:

* install new version
* keep old version
* VIEW diffs -- this is useless because you can't do anything with them
AFAIK but _view_ the differences.
* three way diff view

...and there might be some others, but nowhere do I see a way to launch
a user defined diff tool to interactively merge changes. 

Please tell me this is possible.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.ubuntu.com/archives/ubuntu-users/attachments/20090306/355df2b5/attachment.html>