<p>Every time I do an <code>hg diff file.ext</code> I end up using a console diff application. I would like to use Kdiff3 or WinMerge (I'm using Windows).</p>

<p>Is there a way to change that? I can't find a reference in Mercurial documentation (<strong>I'm not talking about merge!</strong>). </p>

I've solved this using a Mercurial built-in extension... I just have to add the following lines to Mercurial.ini (on Mercurial folder):
```
```
[extensions]
hgext.extdiff=

[extdiff]
cmd.vdiff = kdiff3
```
```
When I want to use kdiff3 instead of diff I only have to use:
```
```
hg vdiff file.ext
```
```