In.gitconfig
file I setup up the git diff as follows:
[diff]
tool = kdiff3
[difftool \"kdiff3\"]
path = path_directory/kdiff3.app
Download kdiff3 and install as app(drag and drop the kdiff3 into your Applications): http://sourceforge.net/projects/kdiff3/files/kdiff3/0.9.98/kdiff3-0.9.98-MacOSX-64Bit.dmg/download
Setup git config tool as following, works for me on MacBook Pro:
git config --global merge.tool kdiff3
and:
git config --global mergetool.kdiff3.cmd '/Applications/kdiff3.app/Contents/MacOS/kdiff3 $BASE $LOCAL $REMOTE -o $MERGED'