| md5sum {tools} | R Documentation |
Compute MD5 Checksums
Description
Compute the 32-byte MD5 hashes of one or more files, or a raw vector of bytes.
Usage
md5sum(files, bytes)
Arguments
files |
character. The paths of file(s) whose contents are to be hashed. |
bytes |
raw. Bytes to be hashed.
NB: |
Details
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 md5sum
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 accidentally modified.
Value
If used with files,
a character vector of the same length as files, with names
equal to files (possibly expanded). The elements will be
NA for non-existent or unreadable files, otherwise a
32-character string of hexadecimal digits.
For bytes the result is a single 32-character string.
Source
The underlying C code was written by Ulrich Drepper and extracted from
a 2001 release of glibc.
See Also
Examples
as.vector(md5sum(dir(R.home(), pattern = "^COPY", full.names = TRUE)))
md5sum(bytes=raw())
md5sum(bytes=charToRaw("abc"))