> `git checkout branchname` does nothing except make HEAD point to the commit You probably know this, but since we are being pedantic we might as well get it r

> `git checkout branchname` does nothing except make HEAD point to the commit You probably know this, but since we are being pedantic we might as well get it right: That describes "git reset". "git checkout" does that and record that we are tracking branchname. So any commits will move both HEAD and the branchname reference.