xxhsum1

Usage

Overview

Print or check xxHash (32, 64 or 128 bits) checksums. When no FILE, read standard input, except if it´s the console. When FILE is -, read standard input even if it´s the console.

xxhsum supports a command line syntax similar but not identical to md5sum(1). Differences are:

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xxhsum doesn´t have text mode switch (-t)

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xxhsum doesn´t have short binary mode switch (-b)

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xxhsum always treats files as binary file

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xxhsum has a hash selection switch (-H)

As xxHash is a fast non-cryptographic checksum algorithm, xxhsum should not be used for security related purposes.

xxhsum -b invokes benchmark mode. See OPTIONS and EXAMPLES for details.

Options

-HHASHTYPE

Hash selection. HASHTYPE means 0=XXH32, 1=XXH64, 2=XXH128, 3=XXH3. Alternatively, HASHTYPE 32=XXH32, 64=XXH64, 128=XXH128. Default value is 1 (XXH64)

-sSEED, --seed SEED

Set the unsigned decimal seed used for hashing and checksum verification. The seed is not stored in checksum files, so the same value must be provided when verifying seeded checksums. Default value is 0.

--binary

Accepted for compatibility. This option has no effect because xxhsum always reads files in binary mode.

--tag

Output in the BSD style.

--little-endian

Set output hexadecimal checksum value as little endian convention. By default, value is displayed as big endian.

-V, --version

Displays xxhsum version and exits

-h, --help

Displays help and exits

--

Treat all following arguments as file names. This is useful for file names beginning with -.

Exit status

xxhsum exit 0 on success, 1 if at least one file couldn´t be read or doesn´t have the same checksum as the -c option.

Examples

Output xxHash (64bit) checksum values of specific files to standard output

$ xxhsum -H1 foo bar baz

Output xxHash (32bit and 64bit) checksum values of specific files to standard output, and redirect it to xyz.xxh32 and qux.xxh64

$ xxhsum -H0 foo bar baz > xyz.xxh32
$ xxhsum -H1 foo bar baz > qux.xxh64

Read xxHash sums from specific files and check them

$ xxhsum -c xyz.xxh32 qux.xxh64

Produce a list of files, then generate hashes for that list

$ find . -type f -name ´*.[ch]´ > c-files.txt
$ xxhsum --files-from c-files.txt

Read the list of files from standard input to avoid the need for an intermediate file

$ find . -type f -name ´*.[ch]´ | xxhsum --files-from -

Note that if shell expansion, length of argument list, clarity of use of spaces in filenames, etc allow it then the same output as the previous example can be generated like this

$ xxhsum `find . -name ´*.[ch]´`

Benchmark xxHash algorithm. By default, xxhsum benchmarks xxHash main variants on a synthetic sample of 100 KB, and print results into standard output. The first column is the algorithm, the second column is the source data size in bytes, the third column is the number of hashes generated per second (throughput), and finally the last column translates speed in megabytes per second.

$ xxhsum -b

In the following example, the sample to hash is set to 16384 bytes, the variants to be benched are selected by their IDs, and each benchmark test is repeated 10 times, for increased accuracy.

$ xxhsum -b1,2,3 -i10 -B16384