git diff with vimdiff
git config --global diff.tool vimdiff
git config --global difftool.prompt false
git config --global alias.d difftool
Magnificent Mongoose
git config --global diff.tool vimdiff
git config --global difftool.prompt false
git config --global alias.d difftool
Just specify your local branch1 or remote origin/branch2
git diff branch1 origin/branch2 #show diff referenced from second branch
git diff branch1 branch2 file.txt #show diff only between file.txt