title: remove a line with special character with pattern
body: <p>I'm trying to remove a line with special characters which is not prefixed with <code>\</code>.
  Below are the special characters:</p>
  
  <pre><code>^$%.*+?!(){}[]|\
  </code></pre>
  
  <p>I need to check all the above special characters which is not prefixed with <code>\</code> in 2nd column.
  I'm trying with <code>awk</code> to complete this, but no luck. I want the output as below.</p>
  
  <p>input.txt</p>
  
  <pre><code>1,ap^ple
  2,o$range
  3,bu+tter
  4,gr(ape
  5,sm\(oke
  6,ra\in
  7,pla\\y
  8,wor\+k
  </code></pre>
  
  <p>output.txt</p>
  
  <pre><code>1,ap^ple
  2,o$range
  3,bu+tter
  4,gr(ape
  6,ra\in
  </code></pre>