Rebase branch without parent branch

Question

Firstly, I imagine this is duplicate; I'm guessing there's a name for what I'm trying to do, but I can't find anything about it.

Imagine I have commits:

a1 -- a2 -- b1 -- b2 -- c1 -- c2

Where a, b, and c are branches. I'm trying to get the history so that it is:

     - b1 -- b2
   /
a1 -- a2 -- c1 -- c2

But if I try and rebase c onto a, I understandably get b as well.

Is there a good way to do this?

Maybe the duplicate would be https://stackoverflow.com/questions/29914052/i-cant-understand-the-behaviour-of-git-rebase-onto. — mkrieger1, Jun 25 '19 at 09:04
Possible duplicate of [I can't understand the behaviour of git rebase --onto](https://stackoverflow.com/questions/29914052/i-cant-understand-the-behaviour-of-git-rebase-onto) — Chris Maes, Jun 25 '19 at 09:16

score 4 · Accepted Answer · answered Jun 25 '19 at 09:04

These are multiple steps. The basic operation is git rebase --onto <newbase> <oldbase> <tip> (where newbase and oldbase can be commit hashes or branch names, but tip should be a branch name).

I'm assuming you have branches b and c pointing to commits b2 and c2, respectively.

git rebase --onto a2 b2 c

Result:
```
          - b1 -- b2
        /
a1 -- a2 -- c1 -- c2
```
Note that b1 and b2 are still unchanged, I just had to move them up visually.

git rebase --onto a1 a2 b

Result:

    - b1 -- b2
  /
a1 -- a2 -- c1 -- c2

Rebase branch without parent branch

1 Answers1