You can query whether a process is running by name. You can do this with ps and pipe the output to grep. It’s not hard, but you can do this more quickly with pgrep. You can also kill that process with pkill. Which includes the ability to send a signal.
So, let’s look at closing down iTunes with pkill:
pkill iTunes
Or we can send it with a signal (9):
pkill -9 iTunes
Or you could just grab the pid of a process by name:
pgrep Safari
It might display:
797
And that’s it. Easy Peasy.
