Is it possible to fast forward another branch without checking it out?

In git, I have a branch A. I create another branch B where I create few commits. Then I want to fast forward branch A to branch B.

I know that I can checkout A and do fast forward to the latest commit of B. This operation requires two modifications of working copy: the first to return to A and then revert working copy to B. If new commits on B contain a lot of changes, the operation could be quite slow.

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  • One Solution collect form web for “Is it possible to fast forward another branch without checking it out?”

    Git provides the update-ref command for this purpose

    git update-ref A B
    

    Note: This command is one of the lower-level Git commands and does not provide any safeguards for you to keep from screwing yourself up. If B is not a fast-forward of A it will still update A, potentially making commits unreachable and subject to garbage collection.

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