How do I view 'git diff' output with my preferred diff tool/ viewer?

Question

When I type git diff, I want to view the output with my visual diff tool of choice (SourceGear \"diffmerge\" on Windows). How do I configure git to do this?

Answer 1

I've been using this bit in ~/.gitconfig for a long time:

[diff]
    external = ~/Dropbox/source/bash/git-meld

With git-meld:

#!/bin/bash
if [ "$DISPLAY" = "" ];
then
    diff $2 $5
else
    meld $2 $5
fi

But now I got tired of always using meld in graphical environment, and it's not trivial to invoke the normal diff with this setup, so I switched to this:

[alias]
    v =  "!sh -c 'if [ $# -eq 0 ] ; then git difftool -y -t meld ; else git difftool -y $@ ; fi' -"

With this setup, things like this work:

git v
git v --staged
git v -t kompare
git v --staged -t tkdiff

And I still get to keep the good old git diff.