title: Filtering throung a listed text
body: <p>I have a list of text that looks like this:</p>
  
  <pre><code>function.o U out
  function.o T fail
  function.o U main
  myPart.o T out
  myPart.o U fail
  </code></pre>
  
  <p>and so on...</p>
  
  <p>I want the final list to look like this:</p>
  
  <pre><code>The .o file with U beside it : The .o file with T beside it /the third column they have both/
  </code></pre>
  
  <p>So the example up there would look like this filtered:</p>
  
  <pre><code>function.o : myPart.o /out/
  myPart.o : function.o /fail/
  </code></pre>
  
  <p>So I list only the lines that have the same symbol in the third column (like <em>out</em>, <em>fail</em> and so on). Until now I came up with this:</p>
  
  <pre><code>awk '$3 in t{ln[$3]=t[$3]" -&gt; "$1;next}{t[$3]=$1}END{for(s in ln) print ln[s],"("s")"}' "$file"
  </code></pre>
  
  <p>But that prints everything without accounting for the U/T symbol. Any ideas please?</p>