revert master to especific commit code example

Example 1: github undo last pushed commit

git reset <previous label or sha1>
git commit -am "blabla"
git push -f <remote-name> <branch-name>

Example 2: git command change to previous comit

git checkout <commit_id>
git checkout -b <new branch> <commit_id>
git checkout HEAD~X // x is the number of commits t go back