[git] upload github and commit

$ mkdir ~/Hello-World
$ cd ~/Hello-world
$ touch README
$ git add README (or git add *)
$ git commit -m 'first commit'
$ git remote add origin git@github.com:username/Hello-World.git
$ git push origin master

update remote to your file
$ git pull

update your file to remote
$ git add *
$ git commit -m 'second commit'
$ git push origin master