This module provides a way to obtain filesystem disk space information. This
is a Unix only distribution. If those information needs to be gathered for
Unix and Windows, use Filesys::DfPortable. The only major benefit of using
Filesys::Df over Filesys::DfPortable, is that Filesys::Df supports the use of
open filehandles as arguments.

The module should work with all flavors of Unix that implement the statvfs()
and fstatvfs() calls, or the statfs() and fstatfs() calls. This would include
Linux, *BSD, HP-UX, AIX, Solaris, Mac OS X, Irix, Cygwin, etc ...