There are a number of ways to kill a process if you know the name of the process. Here’s a couple different ways you can accomplish this. We are going to assume that the process we are trying to kill is named irssi

kill $(pgrep irssi)

killall -v irssi

pkill irssi

kill `ps -ef | grep irssi | grep -v grep | awk ‘{print $2}’`

These techniques can be useful in shell scripts, where you wouldn’t know the process ID and would need to restart or kill a process.