The GNU General Public License

arch is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License (GPL) as published by the Free Software Foundation (and reproduced below).

This software 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 (reproduced below) for more details.

I have chosen to use the GPL for this software because I believe it best reflects the duties to society of a software engineer. It is the best license for users, for my fellow engineers, and for society as a whole. As is beginning to be widely appreciated, this license is a startling profound and influential document and is worthy of study in its own right.

In a commercial climate that grew up mostly under proprietary licenses (those that fall far short of protecting the freedoms and promoting the obligations of the GPL), my choice of this license has, at the moment, made it difficult for me to recover the costs of developing arch and to make a profit from my work going forward. Those are very serious problems, in my opinion. Please see also Uh....a Little Help Here?.

                    GNU GENERAL PUBLIC LICENSE
                       Version 2, June 1991

 Copyright (C) 1989, 1991 Free Software Foundation, Inc.
     59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 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.

                    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 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 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; 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
    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 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 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 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 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.

                            NO WARRANTY

  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

            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--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 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 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
License.