hashsum is tool that calculates and verifies file hashes. It's used like a similar sha1sum, md5sum but use fast gost-34.11-2012 and blake cryptographic hash functions.
It is commonly used to verify the integrity of files.
For file checking hashsum use all available CPU cores achieving 4-6 x speedup compared to single-threaded approach.
On the x86-64 Blake3 hash calculation use SIMD available for this CPU (SSE2, SSE4.1 AVX2 AVX512)
Support Linux, FreeBSD, Microsoft Windows
To create a file with an gost-34.11-2012 hash in it, if one is not provided:
$ hashsum -t g256 filename [filename2] ... > GOSTSUM.check
$ hashsum -t g256 * > GOSTSUM.check
Using Blake3
$ hashsum -t b3 filename [filename2] ... > BLAKE3SUM.check
calculate hash from standard input
$ hashsum -t b3 - < input_file
$ hashsum -t g256 -c GOSTSUM.check
"-t g256" parameter is omitted as it is default hash type
"-v" verbose output contain each verified file and hash validation status
$ hashsum -t g256 -c GOSTSUM.check
Blake3 hash verification
$ hashsum -t b3 -c BLAKE3SUM.check
On success returns 0 Returns 1 if any checked file failed hash test. Returns 2 if the check file has incorrectly formatted lines or any of the verified file doesn't exist