ROS learning notes (IV) ROS cannot solve rosdep init or update

If the prompt is
ERROR: unable to process source https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/xxxxx
Or something like that , At the same time, ensure that your machine can go to Baidu , This may be because raw.githubusercontent.com The website is blocked .
The solution is to modify hosts file , Add this site's ip Address

# open hosts file 
sudo gedit /etc/hosts
# Add at the end of the file 
151.101.84.133  raw.githubusercontent.com
# Exit after holding and try again 

You can refer to