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

[NoOp]

On 03/06/2009 11:31 AM, Daevid Vincent wrote:
> 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.
> 
> 

I reckon that we should start you with launchpad...

https://launchpad.net/ubuntu/+source/update-manager
  https://bugs.launchpad.net/ubuntu/+source/update-manager
enter 'diff' in the search field, and the result is:
<https://bugs.launchpad.net/ubuntu/+source/update-manager?field.searchtext=diff&orderby=-importance&search=Search&field.status%3Alist=NEW&field.status%3Alist=INCOMPLETE_WITH_RESPONSE&field.status%3Alist=INCOMPLETE_WITHOUT_RESPONSE&field.status%3Alist=CONFIRMED&field.status%3Alist=TRIAGED&field.status%3Alist=INPROGRESS&field.status%3Alist=FIXCOMMITTED&field.assignee=&field.bug_reporter=&field.omit_dupes=on&field.has_patch=&field.has_no_package=>

First one is what you are looking for:
https://bugs.launchpad.net/ubuntu/+source/update-manager/+bug/15029
[Diff files in a more friendly format]