sum --man

gistfile1.txt

NAME
  cksum,md5sum,sum - print file checksum and block count

SYNOPSIS
  cksum,md5sum,sum [ options ] [ file ... ]

DESCRIPTION
  sum lists the checksum, and for most methods the block count, for each file
  argument. The standard input is read if there are no file arguments. getconf
  UNIVERSE determines the default sum method: att for the att universe, bsd
  otherwise. The default for the other commands is the command name itself. The
  att method is a true sum, all others are order dependent.

  Method names consist of a leading identifier and 0 or more options separated
  by -.

  getconf PATH_RESOLVE determines how symbolic links are handled. This can be
  explicitly overridden by the --logical, --metaphysical, and --physical
  options below. PATH_RESOLVE can be one of:
    logical
          Follow all symbolic links.
    metaphysical
          Follow command argument symbolic links, otherwise don't follow.
    physical
          Don't follow symbolic links.

OPTIONS
  -a, --all       List the checksum for all files. Use with --total to list
                  both individual and total checksums and block counts.
  -b, --binary    Read files in binary mode. This is the default.
  -B, --scale=scale
                  Block count scale (bytes per block) override for methods that
                  include size in the output. The default is method specific.
  -c, --check     Each file is interpreted as the output from a previous sum.
                  If --header or --permissions was specified in the previous
                  sum then the checksum method is automatically determined,
                  otherwise --method must be specified. The listed checksum is
                  compared with the current value and a warning is issued for
                  each file that does not match. If file was generated by
                  --permissions then the file mode, user and group are also
                  checked. Empty lines, lines starting with #<space>, or the
                  line # are ignored. Lines containing no blanks are
                  interpreted as [no]name[=value] options:
                    method=name
                          Checksum method to apply to subsequent lines.
                    permissions
                          Subsequent lines were generated with --permissions.
  -h, --header    Print the checksum method as the first output line. Used with
                  --check and --permissions.
  -l, --list      Each file is interpreted as a list of files, one per line,
                  that is checksummed.
  -p, --permissions
                  If --check is not specified then list the file mode, user and
                  group between the checksum and path. User and group matching
                  the caller are output as -. If --check is specified then the
                  mode, user and group for each path in file are updated if
                  necessary to match those in file. A warning is printed on the
                  standard error for each changed file.
  -R, --recursive Recursively checksum the contents of directories.
  -S, --silent|status
                  No output for --check; 0 exit status means all sums matched,
                  non-0 means at least one sum failed to match. Ignored for
                  --permissions.
  -t, --text      Read files in text mode (i.e., treat \r\n as \n).
  -T, --total     List only the total checksum and block count of all files.
                  --all --total lists each checksum and the total. The total
                  checksum and block count may be different from the checksum
                  and block count of the catenation of all files due to partial
                  blocks that may occur when the files are treated separately.
  -w, --warn      Warn about invalid --check lines. On by default; -w means
                  --nowarn.
  -x, --method|algorithm=method
                  Specifies the checksum method to apply. Parenthesized method
                  options are readonly implementation details.
                    att|sys5|s5|default
                          The system 5 release 4 checksum. This is the default
                          for sum when getconf UNIVERSE is att. This is the
                          only true sum; all of the other methods are order
                          dependent.
                    ast4|32x4|tw
                          The ast 128 bit PRNG hash generated by catenating 4
                          separate 32 bit PNRG hashes. The block count is not
                          printed.
                    bsd|ucb
                          The BSD checksum.
                    crc   32 bit CRC (cyclic redundancy check).
                            polynomial=mask
                                  The 32 bit crc polynomial bitmask with
                                  implicit bit 32. The default value is
                                  0xedb88320.
                            done[=number]
                                  XOR the final crc value with number.
                                  0xffffffff is used if number is omitted. The
                                  option value may be omitted. The default
                                  value is 0.
                            init[=number]
                                  The initial crc value. 0xffffffff is used if
                                  number is omitted. The option value may be
                                  omitted. The default value is 0.
                            rotate
                                  XOR each input character with the high order
                                  crc byte (instead of the low order).
                            size[=number]
                                  Include the total number of bytes in the crc.
                                  number, if specified, is first XOR'd into the
                                  size. The option value may be omitted. The
                                  default value is 0.
                    prng  32 bit PRNG (pseudo random number generator) hash.
                            mpy=number
                                  The 32 bit PRNG multiplier. The default value
                                  is 0x01000193.
                            add=number
                                  The 32 bit PRNG addend. The default value is
                                  0.
                            init[=number]
                                  The PRNG initial value. 0xffffffff is used if
                                  number is omitted. The option value may be
                                  omitted. The default value is 0x811c9dc5.
                    md5|MD5
                          The RSA Data Security, Inc. MD5 Message-Digest
                          Method, 1991-2, used with permission. The block count
                          is not printed.
                            (version)
                                  md5 (RSA Data Security, Inc. MD5
                                  Message-Digest, 1991-2) 1996-02-29
                    sha1|SHA1|sha-1|SHA-1
                          FIPS 180-1 SHA-1 secure hash algorithm 1.
                            (version)
                                  sha1 (FIPS 180-1) 1996-09-26
                            (author)
                                  Steve Reid <steve@edmweb.com>
                    sha256|sha-256|SHA256|SHA-256
                          FIPS SHA-256 secure hash algorithm.
                            (version)
                                  sha-256 (FIPS) 2000-01-01
                            (author)
                                  Aaron D. Gifford
                    sha384|sha-384|SHA384|SHA-384
                          FIPS SHA-384 secure hash algorithm.
                            (version)
                                  sha-384 (FIPS) 2000-01-01
                            (author)
                                  Aaron D. Gifford
                    sha512|sha-512|SHA512|SHA-512
                          FIPS SHA-512 secure hash algorithm.
                            (version)
                                  sha-512 (FIPS) 2000-01-01
                            (author)
                                  Aaron D. Gifford
                    posix|cksum|std|standard
                          The posix 1003.2-1992 32 bit crc checksum. This is
                          the default cksum(1) method. Shorthand for
                          crc-0x04c11db7-rotate-done-size.
                    zip   The zip(1) crc. Shorthand for
                          crc-0xedb88320-init-done.
                    fddi  The FDDI crc. Shorthand for
                          crc-0xedb88320-size=0xcc55cc55.
                    fnv|fnv1
                          The Fowler-Noll-Vo 32 bit PRNG hash with non-zero
                          initializer (FNV-1). Shorthand for
                          prng-0x01000193-init=0x811c9dc5.
                    ast|strsum
                          The ast strsum(3) PRNG hash. Shorthand for
                          prng-0x63c63cd9-add=0x9c39c33d.
  -L, --logical|follow
                  Follow symbolic links when traversing directories. The
                  default is determined by getconf PATH_RESOLVE.
  -H, --metaphysical
                  Follow command argument symbolic links, otherwise don't
                  follow symbolic links when traversing directories. The
                  default is determined by getconf PATH_RESOLVE.
  -P, --physical  Don't follow symbolic links when traversing directories. The
                  default is determined by getconf PATH_RESOLVE.
  -r, --bsd       Equivalent to --method=bsd --scale=512 for compatibility with
                  other sum(1) implementations.
  -s, --sysv      Equivalent to --method=sys5 for compatibility with other
                  sum(1) implementations.

SEE ALSO
  getconf(1), tw(1), uuencode(1)

IMPLEMENTATION
  version         sum (AT&T Research) 2012-04-20
  author          Glenn Fowler <glenn.s.fowler@gmail.com>
  author          David Korn <dgkorn@gmail.com>
  copyright       Copyright (c) 1992-2015 AT&T Intellectual Property
  license         http://www.eclipse.org/org/documents/epl-v10.html