Free software
means that the software's users have
freedom. (The issue is not about price.) We developed the GNU
operating system so that users can have freedom in their
computing.
Specifically, free software means users have
the
four essential freedoms
:
(0) to run the program, (1) to study and change the program in source
code form, (2) to redistribute exact copies, and (3) to distribute
modified versions.
Software differs from material objects—such as chairs,
sandwiches, and gasoline—in that it can be copied and changed
much more easily. These facilities are why software is useful; we
believe a program's users should be free to take advantage of them,
not solely its developer.