   NETHACK GENERAL PUBLIC LICENSE
   (Copyright 1989 M. Stephenson)

 (Based on the BISON general public license,
  copyright 1988 Richard M. Stallman)

Everyone is permitted to copy and distribute
verbatim copies of this license, but changing it
is not allowed.  You can also use this wording
to make the terms for other programs.

The license agreements of most software companies
keep you at the mercy of those companies.  By
contrast, our general public license is intended
to give everyone the right to share NetHack.  To
make sure that you get the rights we want you to
have, we need to make restrictions that forbid
anyone to deny you these rights or to ask you to
surrender the rights.  Hence this license
agreement.

Specifically, we want to make sure that you have
the right to give away copies of NetHack, that
you receive source code or else can get it if you
want it, that you can change NetHack or use
pieces of it in new free programs, and that you
know you can do these things.

To make sure that everyone has such rights, we
have to forbid you to deprive anyone else of
these rights.  For example, if you distribute
copies of NetHack, 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 tell them their rights.

Also, for our own protection, we must make
certain that everyone finds out that there is no
warranty for NetHack.  If NetHack is modified by
someone else and passed on, we want its
recipients to know that what they have is not
what we distributed.

Therefore we (Mike Stephenson and other holders
of NetHack copyrights) make the following terms
which say what you must do to be allowed to
distribute or change NetHack.  

        COPYING POLICIES

1. You may copy and distribute verbatim copies
of NetHack source code as you receive it, in any
medium, provided that you keep intact the notices
on all files that refer to copyrights, to this
License Agreement, and to the absence of any
warranty; and give any other recipients of the
NetHack program a copy of this License Agreement
along with the program.

2. You may modify your copy or copies of NetHack
or any portion of it, and copy and distribute
such modifications under the terms of Paragraph 1
above (including distributing this License
Agreement), provided that you also do the
following:

 a) cause the modified files to carry prominent
notices stating that you changed the files and
the date of any change; and 

 b) cause the whole of any work that you
distribute or publish, that in whole or in part
contains or is a derivative of NetHack or any
part thereof, to be licensed at no charge to all
third parties on terms identical to those
contained in this License Agreement (except that
you may choose to grant more extensive warranty
protection to some or all third parties, at your
option)

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

3. You may copy and distribute NetHack (or a
portion or derivative of it, under Paragraph 2)
in object code or executable form under the terms
of Paragraphs 1 and 2 above provided that you
also do one of the following: 

 a) accompany it with the complete machine-
readable source code, which must be distributed
under the terms of Paragraphs 1 and 2 above; or,

 b) accompany it with full information as to how
to obtain the complete machine-readable source
code from an appropriate archive site.  (This
alternative is allowed only for noncommercial
distribution.)

For these purposes, complete source code means
either the full source distribution as originally
released over Usenet or updated copies of the
files in this distribution used to create the
object code or executable.

4. You may not copy, sublicense, distribute or
transfer NetHack except as expressly provided
under this License Agreement.  Any attempt
otherwise to copy, sublicense, distribute or
transfer NetHack is void and your rights to use
the program under this License agreement shall be
automatically terminated.  However, parties who
have received computer software programs from you
with this License Agreement will not have their
licenses terminated so long as such parties
remain in full compliance.

Stated plainly:  You are permitted to modify
NetHack, or otherwise use parts of NetHack,
provided that you comply with the conditions
specified above; in particular, your modified
NetHack or program containing parts of NetHack
must remain freely available as provided in this
License Agreement.  In other words, go ahead and
share NetHack, but don't try to stop anyone else
from sharing it farther.
