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OS X Process-Fu 101

OS X is of course a variety of BSD Unix, not Linux. Often is the case where Linux commands either don't work, or don't give the same results on OS X as they do on Linux. For example, a basic 
netstat
will give you a long list of the processes making network connections on your box. On Linux, various command line options can help you drill down from there, to get the answers to more specific queries. On OS X, those same queries don't give you the answers you're seeking. This isn't a compare and contrast article between Linux and OSX. Instead, I'm just noting various commands that can give answers to some basic questions. On OS X, for example, to get an answer to the question: "What process is running on port 50224?" we would use: 
sudo lsof -Pn | grep 50224
This will give you a list of everything connected to port 50224, sans any kind of headings. A much more abbreviated command that will give you essentially the same things, but with column headings as well, is: 
sudo lsof -i :50224
Now, suppose we wanted to get a listing of all processes making network connections from our (OS X) box, including their Command Name, PID, Type of connection, and the Port they're listing to (along with other info)? 
lsof -i -P | less
This command gives all this, with a heading at the top. Piping to less is optional.
Another thing that often comes up is finding out if a certain process is running, let's call it foo: 
ps aux | grep foo
This will show whether or not foo is indeed running, and if it is, what its PID is. From there, if *foo* is unwanted, it can be killed with: 
kill -9 foo
Just as a note: in some cases, you may need to: 
sudo
the above commands.
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