title: git pull: permission denied
body: <p>I created a repository in my desktop and push to github, then clone that repository to my laptop to make development, later committed the changes and push to github. now back to my desktop, i tried 'git pull' to get all the changed i made, it showed the error message:
  Permission denied (publickey)
  fatal: The remote end hung up unexpectedly.</p>
  
  <p>how could this happen? i push the repository to github originally from my desktop it know the remote, now it complained permission denied?</p>