gpg: no valid OpenPGP data found.

•  错误

$ curl -s https://raw.githubusercontent.com/ros/rosdistro/master/ros.asc | sudo apt-key add -
gpg: no valid OpenPGP data found.

• 解决办法

curl -O https://raw.githubusercontent.com/ros/rosdistro/master/ros.asc

sudo apt-key add ros.asc