fork代码和原仓库同步以及已经处理存在remote upstream already exists code example

https://blog.youkuaiyun.com/myuantao3286286/article/details/50477139

remote upstream already exists code example
Example 1: fatal: remote origin already exists.
git remote rm origin
Example 2: fatal: remote origin already exists.
$ git remote set-url origin git@github.com:ppreyer/first_app.git