What does the ~ mean after the branch of a git rebase --onto?

Question

In the example that the Git docs give for git rebase --onto its not clear about what the ~ means

A range of commits could also be removed with rebase. If we have the following situation:

enter code here E---F---G---H---I---J topicA

then the command

git rebase --onto topicA~5 topicA~3 topicA

would result in the removal of commits F and G:

E---H'---I'---J' topicA

This is useful if F and G were flawed in some way, or should not be part of topicA. Note that the argument to --onto and the parameter can be any valid commit-ish.

Does topicA~5 mean 5 commits from the head of topicA? (So counting backwards?)

I cant think of anything else that it would mean but I want to be sure before i try it on my repo.

Answer 1

This is from git rev-parse

<rev>~<n>, e.g. master~3

A suffix ~<n> to a revision parameter means the commit object that is the <n>th generation ancestor of the named commit object, following only the first parents.
I.e. <rev>~3 is equivalent to <rev>^^^ which is equivalent to <rev>^1^1^1.

So in your case, yes, topicA~5 mean 5 commits from the head of topicA: commit E.