title: What does the k parameter do in the sort function (Linux Bash Scripting)?
body: <p>From Linux manual:
  sort via a key; KEYDEF gives location and type.</p>
  
  <p>I have no idea what that means but I saw it being used like this:</p>
  
  <pre><code>cut -f 2 *ptt | tail -n +4 | sort | uniq -c | sort -k1 -rn
  </code></pre>
  
  <p>And then again like this:</p>
  
  <pre><code>ls -1 *\.flv | sort -n -k1.2
  </code></pre>