title: Finding the unique elements in a column of a data from terminal/Unix
body: <p>So, I have a dataset which is of the format:</p>
  
  <pre><code>BBS1    Bbs1    reg 7   Heart
  ASAP2   Asap2   reg 5   Heart
  SPATA22 Spata22 reg 1   Heart
  MYLK4   Mylk4   reg 1   Heart
  ATP8A1  Atp8a1  reg 5   Heart
  </code></pre>
  
  <p>Now the organ name (here Heart) can be different. I there are several organs that the data is about. I am wondering how I can figure out the names of  the unique elements of that column(column 5)? The data file is huge.</p>