Everyone is permitted to copy and distribute verbatim copies of
this license document, but changing it is not allowed.
The licenses for most software are designed to take away your
freedom to share and change it. By contrast, the GNU General
Public License is intended to guarantee your freedom to share
and change free software--to make sure the software is free for all
its users. This General Public License applies to most of the Free
Software Foundation’s software and to any other program whose
authors commit to using it. (Some other Free Software Foundation
software is covered by the GNU Library General Public License
instead.) You can apply it to your programs, too.
When we speak of free software, we are referring to freedom, not
price. Our General Public Licenses are designed to make sure that
you have the freedom to distribute copies of free software (and
charge for this service if you wish), that you receive source code or
can get it if you want it, that you can change the software or use
pieces of it in new free programs; and that you know you can do
To protect your rights, we need to make restrictions that forbid
anyone to deny you these rights or to ask you to surrender the
rights. These restrictions translate to certain responsibilities for
you if you distribute copies of the software, or if you modify it.
For example, if you distribute copies of such a program, whether
gratis or for a fee, you must give the recipients all the rights that
you have. You must make sure that they, too, receive or can get
the source code. And you must show them these terms so they
know their rights.