title: Append string on grep multiple results in a single command
body: <p>I want to append a string on the every line from the grep result. </p>
  
  <p>For example, this command will return several lines:</p>
  
  <pre><code>ls -a | grep "filename"
  </code></pre>
  
  <p>For example:</p>
  
  <pre><code>filename1
  filename2
  filename3
  filename4
  </code></pre>
  
  <p>How can I append a string <code>test</code> on each return line using a single command? So that I get this output:</p>
  
  <pre><code>test filename1
  test filename2
  test filename3
  test filename4
  </code></pre>