patch to the well-known digest package. The output is the same for
files, but if rdigest is given a directory as an argument, it will
recursively checksum the directory in such a manner as to:
(1) give a repeatable checksum
(2) with no regard for file ownership
(3) or timestamps
(4) or modes
(5) while taking into account empty files and directories
such that the checksum of an extracted tar file will match the
checksum of the same tree as retrieved via cvs, or two allegedly
matching trees from different cvs servers, etc.
