b3sum - Man Page

• Calculate the BLAKE3 checksum for one or more files: b3sum path/to/file1 path/to/file2 ...
• Calculate and save the list of BLAKE3 checksums to a file: b3sum path/to/file1 path/to/file2 ... > path/to/file.b3
• Calculate a BLAKE3 checksum from stdin: command | b3sum
• Read a file of BLAKE3 checksums and filenames and verify all files have matching checksums: b3sum --check path/to/file.b3
• Only show a message for missing files or when verification fails: b3sum --check --quiet path/to/file.b3
• Check a known BLAKE3 checksum of a file: echo known_blake3_checksum_of_the_file path/to/file | b3sum --check

tldr.sh

b3sum [Options] [FILE]...

--keyed

Use the keyed mode, reading the 32-byte key from stdin

--derive-key <CONTEXT>

Use the key derivation mode, with the given context string

Cannot be used with --keyed.

-l,  --length <LEN>

The number of output bytes, before hex encoding

[default: 32]

--seek <SEEK>

The starting output byte offset, before hex encoding

[default: 0]

--num-threads <NUM>

The maximum number of threads to use

By default, this is the number of logical cores. If this flag is omitted, or if its value is 0, RAYON_NUM_THREADS is also respected.

--no-mmap

Disable memory mapping

Currently this also disables multithreading.

--no-names

Omit filenames in the output

--raw

Write raw output bytes to stdout, rather than hex

--no-names is implied. In this case, only a single input is allowed.

-c,  --check

Read BLAKE3 sums from the [FILE]s and check them

--quiet

Skip printing OK for each checked file

Must be used with --check.

-h,  --help

Print help (see a summary with '-h')

-V,  --version

Print version