move branch so that it branches off from master in git

Question

i made a mistake so my branch now is:

master -> a -> b

but its suppose to be

master -> a
master -> b

now b has a's changes and now ive committed a bunch of stuff on b already. is there any way i can do so branch b braches off from master and not from a?

Answer 1

这个确切的情况在git rebase手册中作为示例显示：

git rebase --onto master a b