For example, I forked a project two days ago, and today I cloned my forked project locally. I found that the original project has been updated yesterday. How can I keep the local project and the project I forked on github in sync with the original project?
Remotely pull update projects. First add the original package as remote to the local project:
git remote add upstream A_REPOSITORY_URL
Pull remote code
git pull upstream master
Finally commit to your own fork:
git push origin master
The correct answer upstairs is to usually update the master locally and then merge it into your own branch.