Git diffadd

git diffadd is a GUI alternative to git add -p. It allows you to pick and choose parts of a file to add.

Add diffadd to your path and then add the following to your .gitconfig

[alias]
  diffadd = "!cd \"$GIT_PREFIX\"; diffadd"

Then you can do git diffadd

This has been tested using Diffmerge and Meld