GPL(7) GNU GPL(7)

NAME
gpl - GNU General Public License

DESCRIPTION
GNU GENERAL PUBLIC LICENSE

Version 2, June 1991

Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.

Preamble

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.

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 li‐
censee 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 con‐
tents constitute a work based on the Program (independent of having been made by running the Program). Whether that is
true depends on what the Program does.

1. You may copy and distribute verbatim copies of the Program's source code as you receive it, in any medium, provided that
you conspicuously and appropriately publish on each copy an appropriate copyright notice and disclaimer of warranty;
keep intact all the notices that refer to this License and to the absence of any warranty; and give any other recipients
of the Program a copy of this License along with the Program.

You may charge a fee for the physical act of transferring a copy, and you may at your option offer warranty protection
in exchange for a fee.

2. You may modify your copy or copies of the Program or any portion of it, thus forming a work based on the Program, and
copy and distribute such modifications or work under the terms of Section 1 above, provided that you also meet all of
these conditions:

a. You must cause the modified files to carry prominent notices stating that you changed the files and the date of any
change.

b. You must cause any work that you distribute or publish, that in whole or in part contains or is derived from the
Program or any part thereof, to be licensed as a whole at no charge to all third parties under the terms of this Li‐
cense.

c. If the modified program normally reads commands interactively when run, you must cause it, when started running for
such interactive use in the most ordinary way, to print or display an announcement including an appropriate copy‐
right notice and a notice that there is no warranty (or else, saying that you provide a warranty) and that users may
redistribute the program under these conditions, and telling the user how to view a copy of this License. (Excep‐
tion: if the Program itself is interactive but does not normally print such an announcement, your work based on the
Program is not required to print an announcement.)

These requirements apply to the modified work as a whole. If identifiable sections of that work are not derived from
the Program, and can be reasonably considered independent and separate works in themselves, then this License, and its
terms, do not apply to those sections when you distribute them as separate works. But when you distribute the same sec‐
tions as part of a whole which is a work based on the Program, the distribution of the whole must be on the terms of
this License, whose permissions for other licensees extend to the entire whole, and thus to each and every part regard‐
less of who wrote it.

Thus, it is not the intent of this section to claim rights or contest your rights to work written entirely by you;
rather, the intent is to exercise the right to control the distribution of derivative or collective works based on the
Program.

In addition, mere aggregation of another work not based on the Program with the Program (or with a work based on the
Program) on a volume of a storage or distribution medium does not bring the other work under the scope of this License.

3. You may copy and distribute the Program (or a work based on it, under Section 2) in object code or executable form under
the terms of Sections 1 and 2 above provided that you also do one of the following:

a. Accompany it with the complete corresponding machine-readable source code, which must be distributed under the terms
of Sections 1 and 2 above on a medium customarily used for software interchange; or,

b. Accompany it with a written offer, valid for at least three years, to give any third party, for a charge no more
than your cost of physically performing source distribution, a complete machine-readable copy of the corresponding
source code, to be distributed under the terms of Sections 1 and 2 above on a medium customarily used for software
interchange; or,

c. Accompany it with the information you received as to the offer to distribute corresponding source code. (This al‐
ternative is allowed only for noncommercial distribution and only if you received the program in object code or exe‐
cutable form with such an offer, in accord with Subsection b above.)

The source code for a work means the preferred form of the work for making modifications to it. For an executable work,
complete source code means all the source code for all modules it contains, plus any associated interface definition
files, plus the scripts used to control compilation and installation of the executable. However, as a special excep‐
tion, the source code distributed need not include anything that is normally distributed (in either source or binary
form) with the major components (compiler, kernel, and so on) of the operating system on which the executable runs, un‐
less that component itself accompanies the executable.

If distribution of executable or object code is made by offering access to copy from a designated place, then offering
equivalent access to copy the source code from the same place counts as distribution of the source code, even though
third parties are not compelled to copy the source along with the object code.

4. You may not copy, modify, sublicense, or distribute the Program except as expressly provided under this License. Any
attempt otherwise to copy, modify, sublicense or distribute the Program is void, and will automatically terminate your
rights under this License. However, parties who have received copies, or rights, from you under this License will not
have their licenses terminated so long as such parties remain in full compliance.

5. You are not required to accept this License, since you have not signed it. However, nothing else grants you permission
to modify or distribute the Program or its derivative works. These actions are prohibited by law if you do not accept
this License. Therefore, by modifying or distributing the Program (or any work based on the Program), you indicate your
acceptance of this License to do so, and all its terms and conditions for copying, distributing or modifying the Program
or works based on it.

6. Each time you redistribute the Program (or any work based on the Program), the recipient automatically receives a li‐
cense from the original licensor to copy, distribute or modify the Program subject to these terms and conditions. You
may not impose any further restrictions on the recipients' exercise of the rights granted herein. You are not responsi‐
ble for enforcing compliance by third parties to this License.

7. If, as a consequence of a court judgment or allegation of patent infringement or for any other reason (not limited to
patent issues), conditions are imposed on you (whether by court order, agreement or otherwise) that contradict the con‐
ditions of this License, they do not excuse you from the conditions of this License. If you cannot distribute so as to
satisfy simultaneously your obligations under this License and any other pertinent obligations, then as a consequence
you may not distribute the Program at all. For example, if a patent license would not permit royalty-free redistribu‐
tion of the Program by all those who receive copies directly or indirectly through you, then the only way you could sat‐
isfy both it and this License would be to refrain entirely from distribution of the Program.

If any portion of this section is held invalid or unenforceable under any particular circumstance, the balance of the
section is intended to apply and the section as a whole is intended to apply in other circumstances.

It is not the purpose of this section to induce you to infringe any patents or other property right claims or to contest
validity of any such claims; this section has the sole purpose of protecting the integrity of the free software distri‐
bution system, which is implemented by public license practices. Many people have made generous contributions to the
wide range of software distributed through that system in reliance on consistent application of that system; it is up to
the author/donor to decide if he or she is willing to distribute software through any other system and a licensee cannot
impose that choice.

This section is intended to make thoroughly clear what is believed to be a consequence of the rest of this License.

8. If the distribution and/or use of the Program is restricted in certain countries either by patents or by copyrighted in‐
terfaces, the original copyright holder who places the Program under this License may add an explicit geographical dis‐
tribution limitation excluding those countries, so that distribution is permitted only in or among countries not thus
excluded. In such case, this License incorporates the limitation as if written in the body of this License.

9. The Free Software Foundation may publish revised and/or new versions of the General Public License from time to time.
Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or
concerns.

Each version is given a distinguishing version number. If the Program specifies a version number of this License which
applies to it and ``any later version'', you have the option of following the terms and conditions either of that ver‐
sion or of any later version published by the Free Software Foundation. If the Program does not specify a version num‐
ber of this License, you may choose any version ever published by the Free Software Foundation.

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. For software which is copyrighted by the Free Software Foundation, write to
the Free Software Foundation; we sometimes make exceptions for this. Our decision will be guided by the two goals of
preserving the free status of all derivatives of our free software and of promoting the sharing and reuse of software
generally.

NO WARRANTY

11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLI‐
CABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM ``AS
IS'' WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.

12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO
MAY MODIFY AND/OR REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPE‐
CIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIM‐
ITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE
PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
SUCH DAMAGES.

END OF TERMS AND CONDITIONS

How to Apply These Terms to Your New Programs

If you develop a new program, and you want it to be of the greatest
possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these terms.

To do so, attach the following notices to the program. It is safest
to attach them to the start of each source file to most effectively
convey the exclusion of warranty; and each file should have at least
the ``copyright'' line and a pointer to where the full notice is found.

<one line to give the program's name and a brief idea of what it does.>
Copyright (C) <year> <name of author>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.

Also add information on how to contact you by electronic and paper mail.

If the program is interactive, make it output a short notice like this when it starts in an interactive mode:

Gnomovision version 69, Copyright (C) <year> <name of author>
Gnomovision comes with ABSOLUTELY NO WARRANTY; for details
type `show w'.
This is free software, and you are welcome to redistribute it
under certain conditions; type `show c' for details.

The hypothetical commands show w and show c should show the appropriate parts of the General Public License. Of course, the
commands you use may be called something other than show w and show c; they could even be mouse-clicks or menu items---what‐
ever suits your program.

You should also get your employer (if you work as a programmer) or your school, if any, to sign a ``copyright disclaimer''
for the program, if necessary. Here is a sample; alter the names:

Yoyodyne, Inc., hereby disclaims all copyright interest in the program
`Gnomovision' (which makes passes at compilers) written by James Hacker.

<signature of Ty Coon>, 1 April 1989
Ty Coon, President of Vice

This General Public License does not permit incorporating your program into proprietary programs. If your program is a sub‐
routine library, you may consider it more useful to permit linking proprietary applications with the library. If this is
what you want to do, use the GNU Library General Public License instead of this License.