User's Manual

138
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.