how to kill screen in ubuntu code example

Example 1: linux screen kill attached session

screen -X -S SCREENID kill

Example 2: ubuntu kill process

pidof slack 
9734 9718 9716 9708 9622 9619
sudo kill -9 process_id

pidof apt 
9734 9718 9716 9708 9622 9619
sudo kill -9 9734 9718 9716 9708 9622 9619

Example 3: kill screen session from outside

screen -X -S [session # you want to kill] kill

Example 4: how to kill process ubuntu

ps -ax | grep application name