Getting "Does not point to a valid commit"

Question

I'm trying to rebase my branch onto a remote master, and I'm getting this message, any idea what this means?

git clone https://github.com/yaroslavvb/tensorflow.git
cd tensorflow
git checkout macbook

git remote add tfmain https://github.com/tensorflow/tensorflow.git
git fetch -a 

git rebase --onto tfmain/master

fatal: Needed a single revision
Does not point to a valid commit: tfmain/master

Answer 1

you probably meant

git fetch --all