xxhsum.1.md

xxhsum(1) -- print or check xxHash non-cryptographic checksums
==============================================================

SYNOPSIS
--------

`xxhsum [<OPTION>] ... [<FILE>] ...`  
`xxhsum -b [<OPTION>] ...`

`xxh32sum` is equivalent to `xxhsum -H0`  
`xxh64sum` is equivalent to `xxhsum -H1`


DESCRIPTION
-----------

Print or check xxHash (32 or 64bit) checksums.  When <FILE> is `-`, read
standard input.

`xxhsum` supports a command line syntax similar but not identical to
md5sum(1).  Differences are:
`xxhsum` doesn't have text/binary mode switch (`-b`, `-t`);
`xxhsum` always treats file as binary file;
`xxhsum` has hash bit width 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](#OPTIONS) and [EXAMPLES](#EXAMPLES) for details.

OPTIONS
-------

* `-V`, `--version`:
  Display xxhsum version

* `-H`<HASHTYPE>:
  Hash selection.  <HASHTYPE> means `0`=32bits, `1`=64bits.
  Default value is `1` (64bits)

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

* `-h`, `--help`:
  Display help and exit

**The following four options are useful only when verifying checksums (`-c`)**

* `-c`, `--check`:
  Read xxHash sums from the <FILE>s and check them

* `--quiet`:
  Exit non-zero for improperly formatted checksum lines

* `--strict`:
  Don't print OK for each successfully verified file

* `--status`:
  Don't output anything, status code shows success

* `-w`, `--warn`:
  Warn about improperly formatted checksum lines

**The following options are useful only benchmark purpose**

* `-b`:
  Benchmark mode.  See [EXAMPLES](#EXAMPLES) for details.

* `-B`<BLOCKSIZE>:
  Only useful for benchmark mode (`-b`). See [EXAMPLES](#EXAMPLES) for details.
  <BLOCKSIZE> specifies benchmark mode's test data block size in bytes.
  Default value is 102400

* `-i`<ITERATIONS>:
  Only useful for benchmark mode (`-b`). See [EXAMPLES](#EXAMPLES) for details.
  <ITERATIONS> specifies number of iterations in benchmark. Single iteration
  takes at least 2500 milliseconds. Default value is 3

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

Benchmark xxHash algorithm for 16384 bytes data in 10 times. `xxhsum`
benchmarks xxHash algorithm for 32-bit and 64-bit and output results to
standard output.  First column means algorithm, second column is source data
size in bytes, last column means hash generation speed in mega-bytes per
seconds.

    $ xxhsum -b -i10 -B16384

BUGS
----

Report bugs at: https://github.com/Cyan4973/xxHash/issues/

AUTHOR
------

Yann Collet

SEE ALSO
--------

md5sum(1)