git checkout -b dev origin/dev报错：Cannot update paths and switch to branch 'dev' at the same time.

问题：

git checkout -b dev origin/dev报错：

    Cannot update paths and switch to branch 'dev' at the same time.

解决：

git fetch 

it checkout -b dev origin/dev

原因：

本地还没有这个分支dev在线上的记录