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Telegram/ThirdParty/xxHash/cli/xxhsum.1.md

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+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`,
+`xxh128sum` is equivalent to `xxhsum -H2`.
+
+
+DESCRIPTION
+-----------
+
+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:
+
+* `xxhsum` doesn't have text mode switch (`-t`)
+* `xxhsum` doesn't have short binary mode switch (`-b`)
+* `xxhsum` always treats files as binary file
+* `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
+-------
+
+* `-V`, `--version`:
+  Displays xxhsum version and exits
+
+* `-H`*HASHTYPE*:
+  Hash selection. *HASHTYPE* means `0`=XXH32, `1`=XXH64, `2`=XXH128, `3`=XXH3.
+  Note that `-H3` triggers `--tag`, which can't be skipped
+  (this is to reduce risks of confusion with `-H2` (`XXH64`)).
+  Alternatively, *HASHTYPE* `32`=XXH32, `64`=XXH64, `128`=XXH128.
+  Default value is `1` (XXH64)
+
+* `--binary`:
+  Read 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.
+
+* `-h`, `--help`:
+  Displays help and exits
+
+### The following options are useful only when verifying checksums (-c):
+
+* `-c`, `--check` *FILE*:
+  Read xxHash sums from *FILE* and check them
+
+* `-q`, `--quiet`:
+  Don't print OK for each successfully verified file
+
+* `--strict`:
+  Return an error code if any line in the file is invalid,
+  not just if some checksums are wrong.
+  This policy is disabled by default,
+  though UI will prompt an informational message
+  if any line in the file is detected invalid.
+
+* `--status`:
+  Don't output anything. Status code shows success.
+
+* `-w`, `--warn`:
+  Emit a warning message about each improperly formatted checksum line.
+
+### The following options are useful only benchmark purpose:
+
+* `-b`:
+  Benchmark mode.  See EXAMPLES for details.
+
+* `-b#`:
+  Specify ID of variant to be tested.
+  Multiple variants can be selected, separated by a ',' comma.
+
+* `-B`*BLOCKSIZE*:
+  Only useful for benchmark mode (`-b`). See *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* for details.
+  <ITERATIONS> specifies number of iterations in benchmark. Single iteration
+  lasts approximately 1000 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.
+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
+
+BUGS
+----
+
+Report bugs at: https://github.com/Cyan4973/xxHash/issues/
+
+AUTHOR
+------
+
+Yann Collet
+
+SEE ALSO
+--------
+
+md5sum(1)