title: GNU General Public License (v2): can a company use the licensed software for free?
body: <p>Here is the context of this question: I have code that is to be sold for profit, but I wish to make it available/free to individuals and non-profits, as long as their code remains free.</p>
  
  <p>When a library is released under the GPL v2, can a company use it <em>internally</em> for free?  If they develop software based on it, do they <em>have</em> to release it under the GPL, even if they don't distribute it?  Can they make money by <em>using</em> (not distributing) internally developed software that links to the GPL'ed library, without any compensation for the author?</p>
  
  <p>I am looking for a software license that only allows <em>non-commercial uses</em> (copy, modify, link to); the resulting derived programs must also be free for non-commercial uses.  Is there any software license that does this for non-commercial uses, and prevents <em>any</em> commercial use (including <em>using</em> the software in order to make money)?  It looks like the <strong>Creative Commons licenses</strong> are flexible enough to do something close to that, but I've read against using them for software.  What do you think?</p>
  
  <p>Or maybe is it possible to simply write something like the following?</p>
  
  <p>"This work is released under a dual license:</p>
  
  <ol>
  <li>For non-profit uses: the GPL v2 license.</li>
  <li>For other uses: another license, as long as it is obtained from the original author."</li>
  </ol>
  
  <p>Would this effectively make the program free for non-profit uses (copy, modification, usage,…), while leaving the door open to commercial uses?</p>
  
  <p><strong>Edit</strong>: PS: After reading all the answers and looking for information on the web, I decided that the relevant concept for this question is <em>dual licensing</em>.  There is a host of information on the internet about it, and in particular about how the GPL can fit (or not) in a dual license.</p>