Can some one explain me GNU license?

Question

Can some one answer me few questions concerning GNU license?

* Can I use open source software under the GNU license for commercial purposes?
* Can I sell such software?
* Can I modify such software without owners permission?
* Can I sell access / membership to open source software under the GNU license or sell virtual goods created with such software?
* What legal consequences would I had to suffer if I break the license? (I live in Europe)

Thank you!

Answer 1

Last question first: in both the US and Germany the license has been upheld by the court and the material has held to be copyrighted. As such, you are liable for a statutory penalty for each item you sell in violation of it. I believe the statutory minimum in the US is $ 750.



You MAY use such software for commercial purposes. The only thing to be wary of in using it, aside from license restrictions, is that it ONLY gives you the right to distribute and use computer code freely. It does NOT give you free access to trademarks, images or other material which may be available under a separate copyright. Thus for example most of the Quake and Doom engines are free software. None of the Quake and Doom games are. The levels, designs and gameplay are ID software's. Buy the game and download the engine like I did if you want to play it on Linux.



You can modify such software without permission, however you must distribute the source code to such software -- and when it is a derived work, that is one which REQUIRES Open Source code and libraries to compile, then you must distribute the source code to your work.



You can sell Open Source Software but again, you must distribute the source code freely. You may NOT sell access to the source code. You CAN sell access to your binaries or to virtual goods created with this software if they involve trademarked or copyrighted material. But the SOURCE CODE must be distributed freely.



The key line from GNU's founder is "free as in freedom, not as in beer." If you are willing to do the work to compile this stuff, you should be able to. However this does NOT include everything: MOST programs compiled with GCC, the original GPL program, do NOT fall under the terms of a derived work because they use either standard libraries or custom libraries which use only standard functions. In other words you could probably compile them under any other compiler -- like one which uses Dinkumware's libraries -- and so you don't have to distribute them. By the way you don't HAVE to GIVE away GCC if you use it, though of course people will like you if you do. And if you don't give away or sell anything then you don't have to give away anything you use.

Answer 2

* Can I use open source software under the GNU license for commercial purposes?

Yes

* Can I sell such software?

Yes

* Can I modify such software without owners permission?

Yes

* Can I sell access / membership to open source software under the GNU license or sell virtual goods created with such software?

Yes

* What legal consequences would I had to suffer if I break the license? (I live in Europe)

Same as breaking any other license, really. The GPL folks seem to try to keep an eye out for infractions, but I've never heard of them being super litigative.



Here's the catch with GPL (and other copyleft) licenses. You may sell it, modify it, use pieces of it for other purposes, use it for commercial purposes, whatever.

But if you include GPLed code in your application, it must also be released under the GPL. This doesn't mean you have to make it freely available, but it must be open source. So, when you sell it, you must either provide the source code along with the binary application, or readily provide the source code to any purchasers that request it. Further anyone that purchases an application licensed under the GPL is given the right to freely distribute it.



It gets more complex (albeit better). Just because you release some GPL code in a product, doesn't mean the whole product must necessarily be licensed under GPL. The license allows for "aggregations". What qualifies as an aggregation, what qualifies as a modification, etc. are not entirely clear. Open to debate from copyright lawyers, and open to shear mind-bending confusion from us mere mortals.



Here's the official GPL FAQ. I've always found it useful when I have questions about the GPL:

http://www.gnu.org/licenses/gpl-faq.html

Also, this page specifically deals with how Selling GPL software works, and their philosophy on it:

http://www.gnu.org/philosophy/selling.html



Personally I tend to prefer more permissive licenses, like BSD, but I can understand the logic here.



By the way, you should know, there is also the LGPL which is far more permissive, which is used for some purposes, like the standard C libraries.

Answer 3

You can use software with the GNU Public License (GPL) for any purpose, even commercial purposes.



If you make derived works of software licenses with the GPL, then you can sell the compiled binaries; however, your software must also be licensed with the GPL, and you must make the source code available for free (not necessarily the binaries).



You can modify GPL works without any permission, but the restriction above applies.



You can do pretty much anything with GPL software as long as you don't restrict access to its source code in any way.



If you break the license, then you risk being sued by the Electronic Freedom Foundation (EFF).



Another popular open source license is the BSD license (a derivative of the similar MIT license). If you modify software with the BSD license, you can then apply any license you wish to your work. You can sell it, and you can choose not to make the source code available based on whatever the terms of your new license is.

Answer 4

Yes

Yes

Yes

Yes

Deciphering Nostradamus would be easier than understanding the terms of GNU license!