/** Init **/
mkdir XX
cd ~/XX
git init
touch README
git add README
git commit -m 'first commit'
git remote add origin https://github.com/YYY/XX.git
git push origin master
/** Fork **/
git clone https://github.com/YYY/XX.git
cd XX
git remote add upstream https://github.com/YYY/XX.git
git fetch upstream
git merge upstream/master
/** Update & commit **/
git fetch upstream
git merge upstream/master
// git pull upstream master
git status
git add -A
git commit -m 'commit message'
git push origin master