b2sum: Print or check BLAKE2 digests
b2sum computes a 512-bit checksum for each specified
file. The same usage and options as the
command are supported. See md5sum invocation.
b2sum supports the following options.
Change (shorten) the default digest length.
This is specified in bits and thus must be a multiple of 8.
This option is ignored when
--check is specified,
as the length is automatically determined when checking.