NAME

b2sum - compute and check BLAKE2 message digest

SYNOPSIS

b2sum [OPTION]... [FILE]...

DESCRIPTION

Print or check BLAKE2b (512-bit) checksums. Legacy interface to the cksum utility.

With no FILE, or when FILE is -, read standard input.

Mandatory arguments to long options are mandatory for short options too.

-b, --binary: read in binary mode
-c, --check: read checksums from the FILEs and check them
-l, --length=BITS: digest length in bits; must not exceed the max size and must be a multiple of 8 for blake2b; must be 224, 256, 384, or 512 for sha2 or sha3
--tag: create a BSD-style checksum
-t, --text: read in text mode (default)
-z, --zero: end each output line with NUL, not newline, and disable file name escaping

The following five options are useful only when verifying checksums:

--ignore-missing: don't fail or report status for missing files
--quiet: don't print OK for each successfully verified file
--status: don't output anything, status code shows success
--strict: exit non-zero for improperly formatted checksum lines
-w, --warn: warn about improperly formatted checksum lines
--help: display this help and exit
--version: output version information and exit

The sums are computed as described in RFC 7693. When checking, the input should be a former output of this program. The default mode is to print a line with: checksum, a space, a character indicating input mode ('*' for binary, ' ' for text or where binary is insignificant), and name for each FILE.

There is no difference between binary mode and text mode on GNU systems.

AUTHOR

Written by Padraig Brady and Samuel Neves.

REPORTING BUGS

Report bugs to: bug-coreutils@gnu.org
GNU coreutils home page: https://www.gnu.org/software/coreutils/
General help using GNU software: https://www.gnu.org/gethelp/
Report any translation bugs to https://translationproject.org/team/

COPYRIGHT

Copyright © 2026 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later https://gnu.org/licenses/gpl.html.
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.