Create a new repository, or reuse an existing one.
Generate a new SSH key:
ssh-keygen -t rsa -C "your_email@example.com"
Copy the contents of the file ~/.ssh/id_rsa.pub to your SSH keys in your GitHub account settings (https://github.com/settings/keys).
Windows only: Open Windows Services, enable and start the service OpenSSH Authentication Agent
If you created your key with a different name, add your key on ssh-agent (replace yourkey with the name of your private key):
ssh-add $HOME/.ssh/yourkey
Test SSH key:
$ ssh -T git@github.com
Hi developius! You've successfully authenticated, but GitHub does not provide shell access.
Change directory into the local clone of your repository (if you're not already there) and run:
git remote set-url origin git@github.com:username/your-repository.git
Now try editing a file (try the README) and then do:
$ git commit -am "Update README.md"
$ git push
You should not be asked for a username or password. If it works, your SSH key is correctly configured.