This question regards the GPL license for Open Source software.
Can someone take a software under the GPL license, modify it and sell
it in download form via the internet as a shareware application (with
30 days timeout period.) Modified source code would be distributed for
free.

Links and references/examples would be appreciated.
Please note that I know that RedHat sells Linux distributions in
physical form, but this is not what I am asking. I am talking about:
1) selling the binaries via a digital download (not a CD)
2) adding a timeout to the software the way shareware programs do it
so the user has to pay to keep on using the application

According to the web site of Roxen Internet Software: 
"GPL software allows you may download, use, modify, share and
redistribute, but the one thing you are not permitted to do is to sell
it."
&lt;a href=&quot;<a href="http://pike.roxen.com/download/gpl/">http://pike.roxen.com/download/gpl/</a>&quot;&gt;<a href="http://pike.roxen.com/download/gpl/">http://pike.roxen.com/download/gpl/</a>&lt;/a&gt; 
 
Read the GNU General Public License: 
&lt;a href=&quot;<a href="http://www.gnu.org/copyleft/gpl.html">http://www.gnu.org/copyleft/gpl.html</a>&quot;&gt;<a href="http://www.gnu.org/copyleft/gpl.html">http://www.gnu.org/copyleft/gpl.html</a>&lt;/a&gt; 
 
Quoting from the preamble to GPL: 
&amp;quot;... you can change the software or use pieces of it in new free
programs.&amp;quot;
 
Also consider paragraph 10: 
&amp;quot;10.  If you wish to incorporate parts of the Program into other free
programs whose distribution conditions are different, write to the
author to ask for permission.&amp;quot;
 
Does GNU consider shareware &amp;quot;free&amp;quot;? 
Read the following definition from GNU's web site: 
&amp;quot;Shareware is software which comes with permission for people to
redistribute copies, but says that anyone who continues to use a copy
is required to pay a license fee. Shareware is not free software, or
even semi-free.&amp;quot;
From: &lt;a href=&quot;<a href="http://www.gnu.org/philosophy/categories.html">http://www.gnu.org/philosophy/categories.html</a>&quot;&gt;<a href="http://www.gnu.org/philosophy/categories.html">http://www.gnu.org/philosophy/categories.html</a>&lt;/a&gt; 
 
Search terms: gnu &amp;quot;general public license&amp;quot; 
&lt;a href=&quot;<a href="://www.google.com/search?hl=en&amp;amp;lr=&amp;amp;client=googlet&amp;amp;q=gnu+%22general+public+license%22&amp;amp;btnG=Google+Search">://www.google.com/search?hl=en&amp;amp;lr=&amp;amp;client=googlet&amp;amp;q=gnu+%22general+public+license%22&amp;amp;btnG=Google+Search</a>&quot;&gt;<a href="://www.google.com/search?hl=en&amp;amp;lr=&amp;amp;client=googlet&amp;amp;q=gnu+%22general+public+license%22&amp;amp;btnG=Google+Search">://www.google.com/search?hl=en&amp;amp;lr=&amp;amp;client=googlet&amp;amp;q=gnu+%22general+public+license%22&amp;amp;btnG=Google+Search</a>&lt;/a&gt;
 
I hope this helps.  

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Request for Answer Clarification by philippe2002-ga on 22 May 2002 23:07 PDT

Thanks. 
Now if I check the GPL faq (&lt;a href=&quot;<a href="http://www.gnu.org/licenses/gpl-faq.html">http://www.gnu.org/licenses/gpl-faq.html</a>&quot;&gt;<a href="http://www.gnu.org/licenses/gpl-faq.html">http://www.gnu.org/licenses/gpl-faq.html</a>&lt;/a&gt;)
as well as &lt;a href=&quot;<a href="http://www.gnu.org/philosophy/selling.html">http://www.gnu.org/philosophy/selling.html</a>&quot;&gt;<a href="http://www.gnu.org/philosophy/selling.html">http://www.gnu.org/philosophy/selling.html</a>&lt;/a&gt;, it seems to me
that GPL software can be sold as long as the source code is released.
Nothing prevents that source code to contain some expiration period as
long as the modified source is redistributed, right?
 
For example it seems that the following company is repackaging GPL
stuff and reselling it:
* &lt;a href=&quot;<a href="http://www.gnutellagold.com/">http://www.gnutellagold.com/</a>&quot;&gt;<a href="http://www.gnutellagold.com/">http://www.gnutellagold.com/</a>&lt;/a&gt; 
Could this be legal?  

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Clarification of Answer by juggler-ga on 23 May 2002 00:14 PDT

From the same page that you cite: 
"Specifically, it means that a user is free to run the program, change
the program, and redistribute the program with or without changes."
 
I think you need to ask yourself whether the shareware/timeout scheme
is consistent with that.  

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Request for Answer Clarification by philippe2002-ga on 23 May 2002 07:58 PDT

>>I think you need to ask yourself whether the shareware/timeout scheme 
is consistent with that. 
 
Well this was pretty much my question!  

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Clarification of Answer by juggler-ga on 23 May 2002 10:45 PDT

Well, here's a Usenet discussion of the issue: 
<a href="http://groups.google.com/groups?q=%22sell+gpl%22&amp;hl=en&amp;lr=&amp;ie=UTF8&amp;oe=UTF8&amp;selm=3AA5BCC8.5553F3E8%40mail.com&amp;rnum=3">http://groups.google.com/groups?q=%22sell+gpl%22&amp;hl=en&amp;lr=&amp;ie=UTF8&amp;oe=UTF8&amp;selm=3AA5BCC8.5553F3E8%40mail.com&amp;rnum=3</a>
 
Note how the writer  James A. Robertson (jarober@mail.com) states,
&quot;You can't effectively sell a 'license' under the GPL.&quot;
 
Contrast this with GNU's definition of shareware: 
&quot;Shareware is software which comes with permission for people to 
redistribute copies, but says that anyone who continues to use a copy 
is required to pay a license fee.&quot; 
 
I realize this information is probably not what you want to hear, but
it's out there. I'm just presenting it to you so you can make an
informed decision. 

The person that answered my question about the GPL license does not
know much about this topic. Look at the comments section for the type
of answer I was looking for.

Interesting question, I've written some gpled software in the past,
and this is definitly ethically sketchy if it isn't your software. 
However, if it IS your own software, I would say this is probably
legal.  As the gpl faq says:
http://www.fsf.org/licenses/gpl-faq.html

"Does the GPL allow me to sell copies of the program for money?
    Yes, the GPL allows everyone to do this. The right to sell copies
is part of the definition of free software.

Does the GPL allow me to charge a fee for downloading the program from
my site?
    Yes. You can charge any fee you wish for distributing a copy of
the program. If you distribute binaries by download, you must provide
"equivalent access" to download the source--therefore, the fee to
download source may not be greater than the fee to download the
binary."

So, basically, you can charge as much as you want to download the
binary, registration code or not, as long as the source code is
cheaper to acquire.  I asked one of my friends, and he agrees, and
mentions that Caldera Linux at one point offered a trial version of
the thier product that would work for 30 days before requiring a
registration code, but they also supplied the source code along with
the time limited binary.

Also, one more point, the source must be human readable, and
compilable.  IE, no obfuscation to make it difficult to change the
registration code.  Obfuscated source is generally considered illegal
in the GPL.  However, I can make no gaurantee for any of this, as the
GPL has never been properly tested in court.  Expect public opinion to
be against you if you do this to someone elses software.

So, as long as the modified sourcecode is available freely and not
hidden in an overly hard place to find, you can charge as much as you
want for the binary, and include time limited sections.  After all,
the user is perfectly able to go in and change the code himself. 
Also, the user IS legally allowed to redistribute this modified source
without the time limited screens, so don't try to stop them.

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Clarification of Answer by jzig-ga on 24 May 2002 14:41 PDT

Oh yeah, a few general points.  I would say it IS possible to sell
gpled software binaries in this manner, and make money.  It's the same
as selling shareware that immediatly gets hacked to disable the
registration, it's just LEGAL for the user to do so.  Based on the
fact that hacks come out only a few days after new releases, I would
say this method will be as effective as general shareware.  Besides,
on my lazier days, I'd be willing to pay a few bucks for a precompiled
binary.  This is mostly a note to akeshet below :P  Granted, this
method would not work well at all if you charged a high price.

I'd look for equivalent software under the BSD, MIT or similar
licences. The GPL, assuming you don't have the author's express
permission, will let you do anything but.

http://www.opensource.org/licenses/index.html

Thank you. I definitely understand the BSD and the MIT/X licenses.
Please see my comment above. I don't quite understand what can really
be done with GPL.

The GPL says (basically):
"You can do whatever you want with this software and its source code,
as long as you allow everybody else to do so as well."

You are certainly allowed to build an expiration mechanism into your
program, but this mechanism must be in the source that you distribute
freely to anybody who wants it. If somebody wanted to continue using
your software after the expiration period had run out, they would just
have to change the source code and compile the program with no
expiration feature, and they would be 100% allowed to do so, and would
not have to pay to continue using the software. If the software became
popular, then other people would almost surely begin distributing a
version without the expiration feature to start with, so even
non-programmers would be able to use your software without payment.

It is generally hopeless to try to make money selling GPL software.
All the Linux companies have realized this, and are more oriented to
selling support, expertise, and non-free (ie non-GPL) software to run
on Linux systems.

I don't think the answerer has done a good job here at all.  Juggler
hasn't shown an understanding of the GPL, in contrast to the
relatively large number of Free Software / Linux / Gnu experts that no
doubt visit this site. In fact, what he says about not being allowed
to sell GPL'd software is simply factually incorrect. If you can't
give a clear answer to such a simple question, don't waster the
asker's money. Instead of reading the "answer", I would suggest
reading the GPL itself (http://www.gnu.org/copyleft/gpl.html). It
isn't too long and is written to be understood.

akeshet-ga: 
Thanks you for your comments. I appreciate your input, and I'm glad
you've chosen to contribute comments on this subject.
Just to clarify, though...
You state, "... what he says about not being allowed to sell GPL'd
software is simply factually incorrect." I must note that I never said
that. I referenced a web page that said as much. Feel free to accept
or reject that information.
Thanks again for your comments, and I look forward to seeing you
contribute more of your obvious expertise in this area.

Thank you for the clarification. This is in line with what I thought
is possible. Indeed whether it makes business sense is a very
different issue. By the way the type of software I am contemplating is
Windows applications.

Do you know if there is more info on selling GPL software on the web
besides the links mentionned in this page?