# man > b2sum(1)

> **TLDR:** Calculate BLAKE2 cryptographic checksums.
>
- Calculate the BLAKE2 checksum for one or more files:
  `b2sum {{path/to/file1 path/to/file2 ...}}`
- Calculate and save the list of BLAKE2 checksums to a file:
  `b2sum {{path/to/file1 path/to/file2 ...}} > {{path/to/file.b2}}`
- Calculate a BLAKE2 checksum from `stdin`:
  `{{command}} | b2sum`
- Read a file of BLAKE2 checksums and filenames and verify all files have matching checksums:
  `b2sum {{-c|--check}} {{path/to/file.b2}}`
- Only show a message for missing files or when verification fails:
  `b2sum {{-c|--check}} --quiet {{path/to/file.b2}}`
- Only show a message when verification fails, ignoring missing files:
  `b2sum --ignore-missing {{-c|--check}} --quiet {{path/to/file.b2}}`
- Check a known BLAKE2 checksum of a file:
  `echo {{known_blake2_checksum_of_the_file}} {{path/to/file}} | b2sum {{-c|--check}}`

*Source: tldr-pages*

---

[_B2SUM_(1)](https://www.chedong.com/phpMan.php/man/B2SUM/1/markdown)                                    User Commands                                   [_B2SUM_(1)](https://www.chedong.com/phpMan.php/man/B2SUM/1/markdown)

## NAME
       b2sum - compute and check BLAKE2 message digest

## SYNOPSIS
       **b2sum **[_OPTION_]... [_FILE_]...

## DESCRIPTION
       Print or check BLAKE2b (512-bit) checksums.

       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
              digest  length in bits; must not exceed the max for the blake2 algorithm and must be a
              multiple of 8

       **--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 char‐
       acter  indicating input mode ('*' for binary, ' ' for text or where binary is insignificant),
       and name for each FILE.

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

## AUTHOR
       Written by Padraig Brady and Samuel Neves.

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

## COPYRIGHT
       Copyright © 2023 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)](https://www.chedong.com/phpMan.php/man/cksum/1/markdown)

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

GNU coreutils 9.4                           January 2026                                    [_B2SUM_(1)](https://www.chedong.com/phpMan.php/man/B2SUM/1/markdown)