b2sum (1)

Quick Reference

Calculate BLAKE2 cryptographic checksums.

  • Calculate the BLAKE2 checksum for a file:

b2sum {{filename1}}

  • Calculate BLAKE2 checksums for multiple files:

b2sum {{filename1}} {{filename2}}

  • Read a file of BLAKE2 sums and filenames and verify all files have matching checksums:

b2sum -c {{filename.b2}}

  • Calculate the BLAKE2 checksum from stdin:

{{somecommand}} | shasum


b2sum - compute and check BLAKE2 message digest


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


Print or check BLAKE2 (512-bit) checksums.
With no FILE, or when FILE is -, read standard input.
-b, --binary
read in binary mode
-c, --check
read BLAKE2 sums from the FILEs and check them
-l, --length
digest length in bits; must not exceed the maximum for the blake2 algorithm and must be a multiple of 8
create a BSD-style checksum
-t, --text
read in text mode (default)

The following five options are useful only when verifying checksums:

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


Written by Padraig Brady and Samuel Neves.


GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Report b2sum translation bugs to <https://translationproject.org/team/>


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


GNU coreutils 8.29.13-0a854
Source updated
December 2, 2018
Page created
February 9, 2018
Page generated
December 2, 2018