cksum: Print and verify file checksums
cksum by default computes a cyclic redundancy check (CRC) checksum
for each given file, or standard input if none are given or for a
file of ‘-’.
cksum also supports the -a,--algorithm option to select the
digest algorithm to use.
cksum is the preferred interface
to these digests, subsuming the other standalone checksumming utilities,
which can be emulated using
cksum -a md5 --untagged "$@" etc.
cksum [option]… [file]…
cksum is typically used to ensure that files have not been corrupted,
by comparing the
cksum output for the received files with the
cksum output for the original files (typically given in the
cksum by default prints the POSIX standard CRC checksum
for each file along with the number of bytes in the file,
and the file name unless no arguments were given.
The same usage and options as the
command are supported. See b2sum invocation.
cksum supports the following options.
Compute checksums using the specified digest algorithm.
Supported legacy checksums (which are not supported by --check):
‘sysv’ equivalent to
sum -s‘bsd’ equivalent to
sum -r‘crc’ equivalent to
Supported more modern digest algorithms are:
‘md5’ equivalent to
md5sum‘sha1’ equivalent to
sha1sum‘sha224’ equivalent to
sha224sum‘sha256’ equivalent to
sha256sum‘sha384’ equivalent to
sha384sum‘sha512’ equivalent to
sha512sum‘blake2b’ equivalent to
b2sum‘sm3’ only available through
Output extra information to stderr, like the checksum implementation being used.
Output using the original coreutils format used by the other
standalone checksum utilities like
md5sum for example.
This format has the checksum at the start of the line, and may be
more amenable to further processing by other utilities,
especially in combination with the --zero option.
Note this does not identify the digest algorithm used for the checksum.
See md5sum invocation for details of this format.