Git useful commands

Adding an existing project to GitHub using the command line
https://help.github.com/articles/adding-an-existing-project-to-github-using-the-command-line/

Principle ignored by git: git set local Ignore must ensure that the file to be ignored does not exist on the remote warehouse branch of git. If this file exists on the remote branch, setting ignore locally will not work.
So generally, you can add idea/workspace.xml to the gitignore file, but if you have submitted this file to the git remote repository before doing so, you need to execute the following command: git rm -r --cached .idea .

Introduction to git rebase (basic)
https://blog.csdn.net/hudashi/article/details/7664631/