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GNU GENERAL PUBLIC LICENSE |
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Version 2, June 1991 |
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Copyright (C) 1989, 1991 Free Software Foundation, Inc., |
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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Everyone is permitted to copy and distribute verbatim copies |
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of this license document, but changing it is not allowed. |
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Preamble |
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The licenses for most software are designed to take away your |
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freedom to share and change it. By contrast, the GNU General Public |
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License is intended to guarantee your freedom to share and change free |
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software--to make sure the software is free for all its users. This |
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General Public License applies to most of the Free Software |
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Foundation's software and to any other program whose authors commit to |
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using it. (Some other Free Software Foundation software is covered by |
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the GNU Lesser General Public License instead.) You can apply it to |
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your programs, too. |
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When we speak of free software, we are referring to freedom, not |
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price. Our General Public Licenses are designed to make sure that you |
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have the freedom to distribute copies of free software (and charge for |
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this service if you wish), that you receive source code or can get it |
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if you want it, that you can change the software or use pieces of it |
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in new free programs; and that you know you can do these things. |
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To protect your rights, we need to make restrictions that forbid |
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anyone to deny you these rights or to ask you to surrender the rights. |
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These restrictions translate to certain responsibilities for you if you |
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distribute copies of the software, or if you modify it. |
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For example, if you distribute copies of such a program, whether |
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gratis or for a fee, you must give the recipients all the rights that |
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you have. You must make sure that they, too, receive or can get the |
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source code. And you must show them these terms so they know their |
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rights. |
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We protect your rights with two steps: (1) copyright the software, and |
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(2) offer you this license which gives you legal permission to copy, |
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distribute and/or modify the software. |
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Also, for each author's protection and ours, we want to make certain |
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that everyone understands that there is no warranty for this free |
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software. If the software is modified by someone else and passed on, we |
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want its recipients to know that what they have is not the original, so |
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that any problems introduced by others will not reflect on the original |
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authors' reputations. |
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Finally, any free program is threatened constantly by software |
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patents. We wish to avoid the danger that redistributors of a free |
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program will individually obtain patent licenses, in effect making the |
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program proprietary. To prevent this, we have made it clear that any |
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patent must be licensed for everyone's free use or not licensed at all. |
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The precise terms and conditions for copying, distribution and |
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modification follow. |
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GNU GENERAL PUBLIC LICENSE |
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TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION |
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0. This License applies to any program or other work which contains |
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a notice placed by the copyright holder saying it may be distributed |
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under the terms of this General Public License. The "Program", below, |
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refers to any such program or work, and a "work based on the Program" |
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means either the Program or any derivative work under copyright law: |
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that is to say, a work containing the Program or a portion of it, |
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either verbatim or with modifications and/or translated into another |
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language. (Hereinafter, translation is included without limitation in |
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the term "modification".) Each licensee is addressed as "you". |
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Activities other than copying, distribution and modification are not |
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covered by this License; they are outside its scope. The act of |
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running the Program is not restricted, and the output from the Program |
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is covered only if its contents constitute a work based on the |
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Program (independent of having been made by running the Program). |
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Whether that is true depends on what the Program does. |
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1. You may copy and distribute verbatim copies of the Program's |
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source code as you receive it, in any medium, provided that you |
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conspicuously and appropriately publish on each copy an appropriate |
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copyright notice and disclaimer of warranty; keep intact all the |
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notices that refer to this License and to the absence of any warranty; |
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and give any other recipients of the Program a copy of this License |
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along with the Program. |
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You may charge a fee for the physical act of transferring a copy, and |
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you may at your option offer warranty protection in exchange for a fee. |
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2. You may modify your copy or copies of the Program or any portion |
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of it, thus forming a work based on the Program, and copy and |
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distribute such modifications or work under the terms of Section 1 |
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above, provided that you also meet all of these conditions: |
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a) You must cause the modified files to carry prominent notices |
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stating that you changed the files and the date of any change. |
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b) You must cause any work that you distribute or publish, that in |
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whole or in part contains or is derived from the Program or any |
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part thereof, to be licensed as a whole at no charge to all third |
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parties under the terms of this License. |
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c) If the modified program normally reads commands interactively |
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when run, you must cause it, when started running for such |
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interactive use in the most ordinary way, to print or display an |
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announcement including an appropriate copyright notice and a |
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notice that there is no warranty (or else, saying that you provide |
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a warranty) and that users may redistribute the program under |
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these conditions, and telling the user how to view a copy of this |
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License. (Exception: if the Program itself is interactive but |
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does not normally print such an announcement, your work based on |
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the Program is not required to print an announcement.) |
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These requirements apply to the modified work as a whole. If |
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identifiable sections of that work are not derived from the Program, |
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and can be reasonably considered independent and separate works in |
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themselves, then this License, and its terms, do not apply to those |
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sections when you distribute them as separate works. But when you |
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distribute the same sections as part of a whole which is a work based |
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on the Program, the distribution of the whole must be on the terms of |
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this License, whose permissions for other licensees extend to the |
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entire whole, and thus to each and every part regardless of who wrote it. |
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Thus, it is not the intent of this section to claim rights or contest |
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your rights to work written entirely by you; rather, the intent is to |
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exercise the right to control the distribution of derivative or |
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collective works based on the Program. |
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In addition, mere aggregation of another work not based on the Program |
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with the Program (or with a work based on the Program) on a volume of |
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a storage or distribution medium does not bring the other work under |
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the scope of this License. |
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3. You may copy and distribute the Program (or a work based on it, |
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under Section 2) in object code or executable form under the terms of |
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Sections 1 and 2 above provided that you also do one of the following: |
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a) Accompany it with the complete corresponding machine-readable |
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source code, which must be distributed under the terms of Sections |
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1 and 2 above on a medium customarily used for software interchange; or, |
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b) Accompany it with a written offer, valid for at least three |
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years, to give any third party, for a charge no more than your |
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