---
name: "b2sum"
section: "1"
platform: "linux"
package: "coreutils"
version: "9.12-2"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/b2sum"
---

# b2sum(1)

compute and check BLAKE2 message digest

## 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**(1)](/cksum/1.md) 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\>.\
 Report any translation bugs to: \<https://translationproject.org/team/\>.\
 GNU coreutils home page: \<https://www.gnu.org/software/coreutils/\>\
 General help using GNU software: \<https://www.gnu.org/gethelp/\>

## 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.

## SEE ALSO

[**cksum**(1)](/cksum/1.md)

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