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Now that is useful! With that example, I'm using the 
ps aux
 command with the 
--sort
 option, sorting by the percentage of CPU utilization (
-pcpu
). Then I'm piping 
the output into the 
head
 command, where I'm instructing it to show me only five 
lines (
-n 5
). Essentially, this is giving me a list of the top five processes that have 
used the most CPU since boot time. In fact, I can do the same, but with the most-used 
memory instead:
ps aux --sort=-pmem | head -n 5 
If you want to determine which processes are misbehaving and using a non-ordinary 
amount of memory or CPU, those commands will help you narrow it down. The 
ps
 
command is a very useful command for your admin toolbox. Feel free to experiment 
with it beyond the examples I've provided; you can consult the man pages for the 
ps
 
command to learn even more tricks. In fact, the second section of the man page for 
ps
 
(under examples) gives you even more neat examples to try out.
Now that we know how to inspect running processes, in the next section we'll take 
a look at how to change the priority of the processes to ensure those that are more 
important are given extra attention by the CPU.