Under ubuntu how to boot automatically execute custom scripts?

A: The (assuming that the absolute path from script defined for the ~ / start_test.sh) to add custom scripts under /etc/init.d/ directory, and update the system startup items ordered as follows:

　sudo cp ~/start_test.sh /etc/init.d/

sudo update-rc.d start_test.sh defaults 90 (90为执行的优先级，数字越大，表示越晚执行)