killall5 -9 # If all options fails this is the last option
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
sudo kill -9 process_id
ps -ax | grep application name
kill -9 1234
//where 1234 is process ID and -9 is an option to send a KILL singal
kill -9 $(lsof -i tcp:8000)
kill -KILL PIDnumber ... for example, kill -KILL 12345