git-blame-someone-else
$ git blame-someone-else 'Steve Mao <maochenyan@gmail.com>' 2efb4e3a061a2e8aaa58033e9c13c3e0e5fcde4b Steve Mao is now the author of 2efb4e3. You're officially an asshole.
$ git blame-someone-else 'Steve Mao <maochenyan@gmail.com>' 2efb4e3a061a2e8aaa58033e9c13c3e0e5fcde4b Steve Mao is now the author of 2efb4e3. You're officially an asshole.