B2SUM

Section: User Commands (1)
Updated: February 2026
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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.

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#cksu-b'-b, --binaryX'tty: link'

read in binary mode

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#cksu-c'-c, --checkX'tty: link'

read checksums from the FILEs and check them

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#cksu-l'-l, --length=,BITSX'tty: link'/

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

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#cksu-tag'--tagX'tty: link'

create a BSD-style checksum

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#cksu-t'-t, --textX'tty: link'

read in text mode (default)

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#cksu-z'-z, --zeroX'tty: link'

end each output line with NUL, not newline, and disable file name escaping

 

The following five options are useful only when verifying checksums:

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#cksu-ignor-missing'--ignore-missingX'tty: link'

don't fail or report status for missing files

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#cksu-quiet'--quietX'tty: link'

don't print OK for each successfully verified file

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#cksu-status'--statusX'tty: link'

don't output anything, status code shows success

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#cksu-strict'--strictX'tty: link'

exit non-zero for improperly formatted checksum lines

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#cksu-w'-w, --warnX'tty: link'

warn about improperly formatted checksum lines

X'tty: link https://www.gnu.org/software/coreutils/cksum#cksu-help'--helpX'tty: link'

display this help and exit

X'tty: link https://www.gnu.org/software/coreutils/cksum#cksu-version'--versionX'tty: link'

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

Report Gentoo bugs to: https://bugs.gentoo.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/>  

SEE ALSO

cksum(1)

Full documentation <https://www.gnu.org/software/coreutils/b2sum>
or available locally via: info aq(coreutils) b2sum invocationaq

Packaged by Gentoo (9.10 (p0))
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.

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Index

NAME

SYNOPSIS

DESCRIPTION

The following five options are useful only when verifying checksums:

AUTHOR

REPORTING BUGS

SEE ALSO