Scenario:

You encountered a production issue. Immediately you stopped doing whatever you were working on and started fixing the bug. After fixing the bug you observe that you fixed the bug on a different branch. Now you want to move a certain number of commits from a branch A to branch B.

Solution

To move a small number of commits from A to B, use the git cherry-pick command

Say, you have the following branches

Branch A

P ----- Q ----- R ------ S

Branch B

F ----- G ----- H

(Note: P, Q, R, S, F, G, H are all commit hashes/ids)

and you want to move commits Q & R to B(in front of H). You can do the following by

git checkout branchB
git cherry-pick Q
git cherry-pick R

This will result in

Branch B

F ----- G ----- H ----- Q ----- R

Basically, we first checkout to the branch where we want to add the commits, and cherry-pick the commits we want to move, in the order in which they appear in the first branch. Ensuring that the commits being cherry-picked are in sequential order is important or can result in complications.

Like I said, this method works if the number of commits is small, but to move a large number of commits we can use a better method

git checkout <branchname where commits are to be moved>
git rebase --onto <SHA of most recent commit in branchB> <SHA of the commit before the commit that is to be moved> <SHA of the last commit that is to be moved>
git rebase HEAD <branchname where commits are to be moved>

So, for the above example - moving Q & R to branch B, the commands would be

git checkout branchB
git rebase --onto H P R
git rebase HEAD branchB

These two tricks should be enough for moving commits between branches.

To read more of such git tips visit my blog - https://pranavjoglekarcodes.web.app/blogs/posts/2021/git_tricks_1/