title: Does GPL require RedHat to provide it's OS for free, and hence why CentOS exists?
body: <p>I have a few GPL related questions:</p>
  
  <ol>
  <li><p><strong>Yes</strong> or <strong>No</strong>:  If you sell GPL software commercially, you must make the source code free available?</p></li>
  <li><p><strong>Yes</strong> or <strong>No</strong>:  Since RedHat uses GPL software to make it's commcercial sold RedHat Linux operating system, it must release the RedHat Linux OS freely as required by the GPL.</p></li>
  <li><p><strong>Yes</strong> or <strong>No</strong>:  CentOS exists to satisfy the GPL requirements of providing a free version of it's commercially sold RedHat Linux OS?</p></li>
  </ol>
  
  <hr>
  
  <p>Update:  I've reworded my original question to make it more clear.</p>
  
  <p>Update 2: Note no one has directly answered the questions yet, even though there are 4 responses.</p>