want to automatically squash 20 commits

Question

My topic branch is about 20 commits ahead of where I branched from.

I would like to automatically squash all these commits into the first commit after the branch.

I know I can do this interactively with rebase, but I don't want to interact, just fire off the command.

Answer 1

You could do it this way:

git reset --soft HEAD~20
git commit -m "massive commit"

• The first command moves your topic branch 20 commits back, but preserves the changes in the index (and the working tree)
• Then you create a single commit with all the changes.

A quick way to find the exact commit you want to reset to is to do

git merge-base <topicbranch> <otherbranch>

If the output of that is <commit-ish>, you can then do

git reset --soft <commit-ish>

Answer 2

Why not just check out your original branch, and git merge --squash <other branch>?

Then, git commit will give you a chance to edit the combined commit message.