title: Add at the end of the line with sed
body: <p>given a plain text document with several lines like:</p>
  
  <pre><code>c48 7.587 7.39
  c49 7.508 7.345983
  c50 5.8 7.543
  c51 8.37454546 7.34
  </code></pre>
  
  <p>I need to add some info 2 spaces after the end of the line, so for each line I would get:</p>
  
  <pre><code>c48 7.587 7.39  def
  c49 7.508 7.345983  def
  c50 5.8 7.543  def
  c51 8.37454546 7.34  def
  </code></pre>
  
  <p>I need to do this for thousands of files. I guess this is possible to do with sed, but do not know how to. Any hint? Could you also give me some link with a tutorial or table for this cases?</p>
  
  <p>Thanks</p>