Question

f’I have the following:

A---B---C-----D--   branch dev
     \--C'-E-/      branch test

I did it bad: C and C’ are almost the same commits, it would make more sense if I could make branch test start on C, instead of B.

How could I do that?, I guess rebase, but I’m not sure how to use it, thx

edit: wasn’t clear
what I’d like:

A---B---C-----D--   branch dev
         \-E-/      branch test

or

A–B–D–E–D if not possible

Answer 1

You could rebase it on top of a temporary branch (made from C)
See git rebase and Rebasing, plus git branch.

git branch tmp C
git checkout test

# rebase the current branch (test) on top of tmp
git rebase tmp  

git branch -d tmp

That should give you:

A---B---C-----D--       branch dev
         \--C''-E'-/      branch test

I have left C’ (here as C”) because C’ isn’t exactly the same than C.
But as ams comments, if you need C’ gone, you would

git rebase -i tmp

That would get you an interactive rebase, allowing for C' to be removed completely, replaying only E on top of C.