title: How to add a prefix “#” to lines that contain string “000” in all files in a directory and its sub-directories in linux?
body: <p>This is a 000 line.
  This is 000 yet ano000ther line.
  This is still yet another line.
  If I run the command, it should add # to the front of any lines where "000" was found. The result would be this:</p>
  
  <pre><code>#This is a 000 line.
  #This is 000 yet ano000ther line.
  This is still yet another line.
  </code></pre>