title: Filtering Rows Based On Number of Columns with AWK
body: <p>I have lines of data that contain 
  single column and two columns. What I want to do is to 
  extract lines that contain only 2 columns. </p>
  
  <pre><code>0333 foo
   bar
  23243 qux
  </code></pre>
  
  <p>yielding only:</p>
  
  <pre><code>0333 foo
  23243 qux
  </code></pre>
  
  <p>Note that they are tab separated, even for lines with only one column
  you have tab at the beginning.</p>
  
  <p>What's the way to do it?</p>
  
  <p>I tried this but fail:</p>
  
  <pre><code>awk '$1!="";{print $1 "\t" $2}' myfile.txt
  
  enter code here
  </code></pre>