info > md5sum

File: coreutils.info,  Node: md5sum invocation,  Next: b2sum invocation,  Prev: cksum invocation,  Up: Summarizing files

6.4 'md5sum': Print or check MD5 digests

'md5sum' computes a 128-bit checksum (or "fingerprint" or
"message-digest") for each specified FILE.

   Note: The MD5 digest is more reliable than a simple CRC (provided by
the 'cksum' command) for detecting accidental file corruption, as the
chances of accidentally having two files with identical MD5 are
vanishingly small.  However, it should not be considered secure against
malicious tampering: although finding a file with a given MD5
fingerprint is considered infeasible at the moment, it is known how to
modify certain files, including digital certificates, so that they
appear valid when signed with an MD5 digest.  For more secure hashes,
consider using SHA-2, or the newer 'b2sum' command.  *Note sha2
utilities::.  *Note b2sum invocation::.

   If a FILE is specified as '-' or if no files are given 'md5sum'
computes the checksum for the standard input.  'md5sum' can also
determine whether a file and checksum are consistent.  Synopsis:

     md5sum [OPTION]... [FILE]...

   'md5sum' uses the 'Untagged output format' for each specified file,
as described at *note cksum output modes::.

   The program accepts *note cksum common options::.  Also see *note
Common options::.

   An exit status of zero indicates success, and a nonzero value
indicates failure.