Compute MD5 Checksums
Compute the 32-byte MD5 hashes of one or more files.
- character. The paths of file(s) whose contents are to be hashed.
A MD5 hash or checksum or message digest is a 128-bit summary of the file contents represented by 32 hexadecimal digits. Files with different MD5 sums are different: only very exceptionally (and usually with the intent to deceive) are those with the same sums different.
On Windows all files are read in binary mode (as the
utilities there do): on other OSes the files are read in the default
mode (almost always text mode where there is more than one).
MD5 sums are used as a check that R packages have been unpacked correctly and not subsequently modified.
A character vector of the same length as
files, with names equal to
files. The elements will be
NAfor non-existent or unreadable files, otherwise a 32-character string of hexadecimal digits.
The underlying C code was written by Ulrich Drepper and extracted from
a 2001 release of
as.vector(md5sum(dir(R.home(), pattern = "^COPY", full.names = TRUE)))