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

For a linux version of how to configure a diff tool on git versions prior to 1.6.3 (1.6.3 added difftool to git) this is a great concise tutorial,

in brief:

Step 1: add this to your .gitconfig

[diff]
  external = git_diff_wrapper
[pager]
  diff =

Step 2: create a file named git_diff_wrapper, put it somewhere in your $PATH

#!/bin/sh

vimdiff "$2" "$5"