SHELL

kill all process ubuntu

killall5 -9 # If all options fails this is the last option

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 

kill process ubuntu

sudo kill -9 process_id

how to kill process ubuntu

ps -ax | grep application name 

how to kill a programm in ubuntu?

Go to System Monitor
Search for process name
Click End Process