sudo rosdep init命令出错（ROS安装 ）

ROS安装过程中遇到的报错

sudo rosdep init命令出错：

ERROR: cannot download default sources list from:
https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/sources.list.d/20-default.list
Website may be down.  

则在命令行输入sudo gedit /etc/hosts，在host文件中添加151.101.192.133 raw.githubusercontent.com 然后保存就好了

sudo rm /etc/ros/rosdep/sources.list.d/20-default.list