I had set up my SSH key long ago in my GitHub account. Yet when I git pushed to GitHub, it still asked me for my username and password.
After I double checked my key at https://github.com/settings/keys, I thought it might be that my git settings had been reset? It turns out, the origin URL was wrong. For some reason it was in the form
https://github.com/username/reponame.git. To use the SSH key, it should have been
% git push origin HEAD Username for 'https://github.com': ... % git remote get-url origin https://github.com/username/reponame.git % git remote set-url origin email@example.com:username/reponame.git % git push origin HEAD Everything up-to-date