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 these things.
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.
We protect your rights with two steps: (1) copyright the software, and (2) offer you this
license which gives you legal permission to copy, distribute and/or modify the software.
Also, for each author’s protection and ours, we want to make certain that everyone
understands that there is no warranty for this free software. If the software is modified
by someone else and passed on, we want its recipients to know that what they have is
not the original, so that any problems introduced by others will not reflect on the original
authors’ reputations.
Finally, any free program is threatened constantly by software patents. We wish to avoid
the danger that redistributors of a free program will individually obtain patent licenses, in
effect making the program proprietary. To prevent this, we have made it clear that any
patent must be licensed for everyone’s free use or not licensed at all.
The precise terms and conditions for copying, distribution and modification follow.
GNU GENERAL PUBLIC LICENSE
TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
0. This License applies to any program or other work which contains a notice placed
by the copyright holder saying it may be distributed under the terms of this General
Public License. The “Program”, below, refers to any such program or work, and a
“work based on the Program” means either the Program or any derivative work
under copyright law: that is to say, a work containing the Program or a portion of
it, either verbatim or with modifications and/or translated into another language.
(Hereinafter, translation is included without limitation in the term “modification”.)
Each licensee is addressed as “you”.
Activities other than copying, distribution and modification are not covered by this
License; they are outside its scope. The act of running the Program is not restricted, and
the output from the Program is covered only if its contents constitute a work based on
