git diff --name-status branch1..branch2
git difftool branch1:config/environment.rb branch2:config/environment.rb
http://blog.firsthand.ca/2011/05/compare-git-branches-compare-two-files.html
git diff --name-status branch1..branch2
git difftool branch1:config/environment.rb branch2:config/environment.rb
http://blog.firsthand.ca/2011/05/compare-git-branches-compare-two-files.html