git config --global user.name mschuller
git config --global user.email manfred.schuller@f-i-ts.de

# create ssh key
cd ~/.ssh
ssh-keygen -t ed25519 -C "manfred.schuller@f-i-ts.de"

# copy id_ed25519.pub to GitHub (New SSH key)

ssh -T git@github.com
Hi mschuller! You've successfully authenticated, but GitHub does not provide shell access.

cd <directory>
git init
git status
On branch master
...

# rename master to main
git branch -m master main

git status
On branch main
...

git add .
git commit -m "init commit"
git remote add origin git@github.com:mschuller/<repository>.git

git pull origin main

git branch -a
* main
  remotes/origin/main

git branch -r
  origin/main

git push --set-upstream origin main

git add .
git status
git commit -m "second commit"
git push