git diff 工作区与暂存区的差别
git diff -cached / git diff -staged 暂存区与版本库的差别
git diff HEAD 工作区与版本库的差别
git diff branch1 branch2 两个分支的最新commit的差别
git diff branch1...branch2 自branch1与branch2分开以来，branch2上的变化
git diff --stat 查看简单的diff结果
git diff branch1 查看当前目录与另外一个分支的差别
git diff HEAD -- ./lib 显示当前目录的lib目录和上次提交之间的差别
git diff HEAD^ HEAD 查看上次提交与上上次提交的差别
git diff commit1 commit2 查看两次提交之间的差别
原文：http://www.cnblogs.com/mengff/p/5999574.html