checkMD5sums checks the files against a file MD5.
checkMD5sums(package, dir)the name of an installed package
the path to the top-level directory of an installed package.
checkMD5sums returns a logical, NA if there is no
MD5 file to be checked.
The file MD5 which is created is in a format which can be
checked by md5sum -c MD5 if a suitable command-line version
of md5sum is available. (For Windows, one is supplied in
the bundle at https://cran.r-project.org/bin/windows/Rtools.)
If dir is missing, an installed package of name package
is searched for.
The private function tools:::.installMD5sums is used to create
MD5 files in the Windows build.