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+NAME
+	anysum - compute or verify against multiple checksums
+
+SYNOPSIS
+	anysum (-c [-w] | [-a algoritms] ...) [-W options] ...
+	       [-z] [file] ...
+
+DESCRIPTION
+	The anysum utility can calculate checksums of a file using
+	multiple hash functions, or using different parameters for
+	the function, in parallel (the utility can calculate checksums
+	for multiple files, but these are not calculated in parallel).
+
+	The anysum utility can also check a file against multiple
+	checksums using multiple hash function and hash function
+	parameters in parallel, and check that the file matches at
+	least one of the listed checksums.
+
+OPTIONS
+	The anysum utility conforms to the Base Definitions volume of
+	POSIX.1-2017, Section 12.2, Utility Syntax Guidelines.
+
+	The following options are supported:
+
+	-a algorithms
+		Comma-separated list of hash functions and
+		parameters to compute checksums with.
+
+		Currently supported values are:
+
+		md2
+			For MD2.
+
+		md4
+			For MD4.
+
+		md5
+			For MD5.
+
+		ripemd128 or rmd128
+			For RIPEMD-128.
+
+		ripemd160 or rmd160
+			For RIPEMD-160.
+
+		ripemd256 or rmd256
+			For RIPEMD-256.
+
+		ripemd320 or rmd320
+			For RIPEMD-320.
+
+		sha0
+			For SHA-0.
+
+		sha1
+			For SHA-1.
+
+		sha224
+			For the 224 bit version of SHA-2.
+
+		sha256
+			For the 256 bit version of SHA-2.
+
+		sha384
+			For the 384 bit version of SHA-2.
+
+		sha512
+			For the 512 bit version of SHA-2.
+
+		sha512/224
+			For the 224 bit output variant of the
+			512 (and 384) bit version of SHA-2.
+
+		sha512/256
+			For the 256 bit output variant of the
+			512 (and 384) bit version of SHA-2.
+
+		keccak[r=BITRATE,c=CAPACITY,n=LENGTH,z=SQUEEZES]
+			For Keccak. The brackets and there parameter
+			list, and each parameter, are optional. Any
+			parameter the is skipped is automatically
+			determined. BITRATE and CAPACITY are the
+			Keccak function's bitrate and capacity bit
+			bits, and LENGTH is the hash length is bits.
+			SQUEEZES is the number of squeezes to perform
+			after a input has been feed into the function;
+			the default is one, and any number in excess
+			of this is the number of squeezes to perform
+			before squeezing out the hash.
+
+		keccak-224
+			For Keccak[r=1152,c=448,n=224].
+
+		keccak-256
+			For Keccak[r=1088,c=512,n=256].
+
+		keccak-384
+			For Keccak[r=832,c=768,n=384].
+
+		keccak-512
+			For Keccak[r=576,c=1024,n=512].
+
+		sha3-224
+			For the 224 bit version of SHA-3.
+
+		sha3-256
+			For the 256 bit version of SHA-3.
+
+		sha3-384
+			For the 384 bit version of SHA-3.
+
+		sha3-512
+			For the 512 bit version of SHA-3.
+
+		shake-128[n=LENGTH]
+			For the 128 bit version of SHAKE. The brackets
+			and n=LENGTH are optional; LENGTH shall the
+			output size in bits (default is 128).
+
+		shake-256[n=LENGTH]
+			For the 256 bit version of SHAKE. The brackets
+			and n=LENGTH are optional; LENGTH shall the
+			output size in bits (default is 256).
+
+		shake-512[n=LENGTH]
+			For the 512 bit version of SHAKE. The brackets
+			and n=LENGTH are optional; LENGTH shall the
+			output size in bits (default is 512).
+
+		rawshake-128[n=LENGTH]
+			For the 128 bit version of RawSHAKE. The
+			brackets and n=LENGTH are optional; LENGTH
+			shall the output size in bits (default is 128).
+
+		rawshake-256[n=LENGTH]
+			For the 256 bit version of RawSHAKE. The
+			brackets and n=LENGTH are optional; LENGTH
+			shall the output size in bits (default is 256).
+
+		rawshake-512[n=LENGTH]
+			For the 512 bit version of RawSHAKE. The
+			brackets and n=LENGTH are optional; LENGTH
+			shall the output size in bits (default is 512).
+
+		blake224[salt=SALT] or b224[salt=SALT]
+			For the 224 bit version of BLAKE. The brackets
+			and salt=SALT are optional; SALT shall be a 32
+			character long hexadecimal value.
+
+		blake256[salt=SALT] or b256[salt=SALT]
+			For the 256 bit version of BLAKE. The brackets
+			and salt=SALT are optional; SALT shall be a 32
+			character long hexadecimal value.
+
+		blake384[salt=SALT] or b384[salt=SALT]
+			For the 384 bit version of BLAKE. The brackets
+			and salt=SALT are optional; SALT shall be a 64
+			character long hexadecimal value.
+
+		blake512[salt=SALT] or b512[salt=SALT]
+			For the 512 bit version of BLAKE. The brackets
+			and salt=SALT are optional; SALT shall be a 64
+			character long hexadecimal value.
+
+		The utility does also recognise similar values
+		that are obviously equivalent.
+
+	-b
+		Read in binary mode when computing hashes.
+
+	-c
+		Verify the the files listed in file against the
+		checksums listed on the same lines. The file
+		shall be formatted as the output of the utility
+		when this option is not used. See the STDOUT
+		section for more information. If a file is listed
+		multiple times, it need only match one of the
+		checksums listed for the file.
+
+		The length of the listed checksums need not match
+		the length output by this utility; before the
+		checksums are compared, they are truncated to the
+		shorter of the two checksums.
+
+	-t
+		Read in text mode when computing hashes.
+
+	-W options
+		Comma-sepearated list of implementation-specific
+		options. The following options are supported:
+
+		output=format
+			format shall be "lowercase" if the checksums
+			shall be printed in lowercase hexadecimal
+			format (default), "uppercase" for uppercase
+			hexadecimal format, or "binary" for binary
+			format without anything but the checksum
+			printed to standard output. This option is
+			ignored if the -c option is used.
+
+		input=format
+			format shall be "binary" if the files are
+			be read in binary mode, "text" if the files
+			shall be read in text mode, or "hexadecimal"
+			they shall be decoded from hexadecimal to
+			binary. If the -c option is used, the mode
+			specification associated with a file is
+			overrides this behaviour for that file if
+			the line specifies hexadecimal mode.
+
+		threads=count
+			The maximum number of threads that the
+			utility may use. If "auto" is specified,
+			the utility selects a default value, which
+			currently is the number of online CPU threads
+			(at any time; assumed to be 8 if it cannot
+			be determined) minus 2, or 1 if this would
+			be less than 1.
+
+		recursive
+			If a file operand is a directory, the checksum
+			is computed for all files recursively.
+			This option is ignored if the -c option is
+			used.
+
+		no-recursive
+			The utility shall traverse directories.
+			(This is the default behaviour).
+
+	-w
+		Warn about, but skip, lines that are not properly
+		formatted.
+
+	-z
+		Use NUL byte as line ending instead of LF.
+
+	There is no difference between binary mode and text mode,
+	so the -b and -t options are ignored.
+
+OPERANDS
+	The following operand is supported:
+
+	file
+		The file to read and compute the checksum for, or if
+		the -c option is used, use as the listing of files
+		and checksums to verify the files against. If dash
+		('-') is used or if no file operand is specified,
+		standard input will be used.
+
+STDOUT
+	If the -c option is not used, the utility shall print the
+	following line for each calculated checksum, however there
+	are options that modify the format; see the OPTIONS section
+	for more information:
+
+		"%s:%s %c%s\n", <hash function>, <hash>, <mode>,
+		<file>
+
+	where <mode> is SP (' ') for text mode, an asterisk ('*')
+	for binary mode, or a pound sign ('#') for hexadecimal
+	mode; however if there is no difference between binary
+	mode and text mode and either is selected, SP (' ')
+	(text mode) is used.
+
+	If the -c option the output shall be on the format:
+
+		"%s: %s\n", <file>, <validity>
+
+	where <validity> is an implementation specified string
+	that describes whether the checksum was valid (possibly
+	with remarks), the file did not exist, the file could
+	not be read (possibly with error information), or if
+	the checksum was invalid or could not be compared
+	(possibly with remarks). The -z option does not modify
+	the line ending.
+
+EXIT STATUS
+	The following exit values are returned:
+
+	0	Successful completion.
+
+	1	Checksums did not match or a file did not exist.
+
+	2	An error occurred.
+
+NOTES
+	Other implementations do not necessarily recognise the
+	'#' mode specifier in checksum list files.