R: Compute MD5 Checksums

md5sum {tools} | R Documentation

## Compute MD5 Checksums

### Description

Compute the 32-byte MD5 hashes of one or more files.

### Usage

    md5sum(files)

### Arguments

`files` | character. The paths of file(s) whose contents are to be hashed.

### 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 modified.

### Value

A character vector of the same length as `files`, with names equal to `files`. The elements will be `NA` for non-existent or unreadable files, otherwise a 32-character string of hexadecimal digits.

### Source

The underlying C code was written by Ulrich Drepper and extracted from a 2001 release of `glibc`.

### See Also

`checkMD5sums`

### Examples

    as.vector(md5sum(dir(R.home(), pattern = "^COPY", full.names = TRUE)))

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