Linux is written and distributed under the GNU General Public License which
means that its source code is freely-distributed and available to the general public.
GNU GENERAL PUBLIC LICENSE
Version 2, June 1991
Copyright (C) 1989, 1991 Free Software Foundation, Inc.
675 Mass Ave, Cambridge, MA 02139, USA
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,
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
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
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 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
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 License.
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 copyright 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. (Exception: 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 sections 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 regardless 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;
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
c) Accompany it with the information you received as to the offer to
distribute corresponding source code. (This alternative is allowed only
for noncommercial distribution and only if you received the program in
object code or executable 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 exception, 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, unless 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 license 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 responsible for enforcing compliance by third parties to this
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 conditions 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 redistribution of the Program by all those who receive copies directly
or indirectly through you, then the only way you could satisfy 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 distribution 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 interfaces, the original copyright holder who
places the Program under this License may add an explicit geographical distribution
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
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 version or of any
later version published by the Free Software Foundation. If the Program does not
specify a version number 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.
11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO
WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE
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, SPECIAL,
INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR
INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED 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
Appendix: 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) 19yy (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., 675 Mass Ave, Cambridge, MA 02139, 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) 19yy 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--whatever 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
(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 subroutine 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