how to undo git commit

revert local commit: http://www.cnblogs.com/ningkyolei/p/4334990.html

http://www.cnblogs.com/0616--ataozhijia/p/4165052.html

When we commit our code to Gerrit, we have to specify the remote branch as ‘refs/for/master’(console commend: git push origin :refs/for/master)

‘refs/for/master’ means find the remote branch which name is ‘master’ and create a code review , the post also explain the refs/heads/master