The program 'roscore' is currently not installed. You can install it by typing: sudo apt install py

安装了ros但是运行roscore出现错误：

The program 'roscore' is currently not installed. You can install it by typing: sudo apt install pyt

解决方法：

source /opt/ros/kinetic/setup.bash
/opt/ros/kinetic/./setup.bash
sudo chmod 777 /opt/ros/kinetic/setup.bash
/opt/ros/kinetic/./setup.bash