Getting started with Git and GitHub
Setting your username in Git→
Git uses a username to associate commits with an identity. The Git username is not the same as your GitHub username.
Caching your GitHub password in Git→
If you're cloning GitHub repositories using HTTPS, you can use a credential helper to tell Git to remember your GitHub username and password every time it talks to GitHub.
Why is Git always asking for my password?→
If Git prompts you for a username and password every time you try to interact with GitHub, you're probably using the HTTPS clone URL for your repository.
Updating credentials from the OSX Keychain→
You'll need to update your saved username and password in the git-credential-osxkeychain helper if you change your password or username on GitHub.