title: How to always cut the PID from `ps aux` command?
body: <p>I'd like to get the pid from my processes.  I do <code>ps aux | cut -d ' ' -f 2</code> but I notice that sometimes it gets the pid and sometimes it does not:</p>
  
  <pre><code>[user@ip ~]$ ps aux 
  user  2049  0.5 10.4 6059216 1623520 ?     Sl   date   8:48 process 
  user 12290  0.3  6.9 5881568 1086244 ?     Sl   date  2:30 
  [user@ip ~]$ ps aux | cut -d ' ' -f 2 
  
  12290
  [user@ip ~]$ ps aux |  cut -d ' ' -f 3
  2049
  </code></pre>
  
  <p>notice that the first <code>cut</code> command is piping it to <code>2</code> whereas the second one is piping it to <code>3</code>.  How do I pick out the PID from these without having to know which number to use (<code>2</code> or <code>3</code>)?</p>
  
  <p>Can someone please tell me the difference between these and why it picks up one and not the other?  </p>