man.postnix Miscellaneous man pages of Plan 9 related material

     SUM(1)                                                     SUM(1)

     NAME
          sum, md5sum, sha1sum - sum and count blocks in a file

     SYNOPSIS
          sum [ -5r ] [ file ... ]

          md5sum [ file ... ]

          sha1sum [ file ... ]

     DESCRIPTION
          By default, sum calculates and prints a 32-bit hexadecimal
          checksum, a byte count, and the name of each file. The
          checksum is also a function of the input length.  If no
          files are given, the standard input is summed.  Other sum-
          ming algorithms are available.  The options are

          -r   Sum with the algorithm of System V's sum -r and print
               the length (in 1K blocks) of the input.

          -5   Sum with System V's default algorithm and print the
               length (in 512-byte blocks) of the input.

          Sum is typically used to look for bad spots, to validate a
          file communicated over some transmission line or as a quick
          way to determine if two files on different machines might be
          the same.

          Md5sum computes the 32 hex digit RSA Data Security, Inc. MD5
          Message-Digest Algorithm described in RFC1321.  If no files
          are given, the standard input is summed.

          Sha1sum computes the 40 hex digit National Institute of
          Standards and Technology SHA1 secure hash algorithm
          described in FIPS PUB 180-1.  If no files are given, the
          standard input is summed.

     SOURCE
          /usr/local/plan9/src/cmd/sum.c
          /usr/local/plan9/src/cmd/md5sum.c
          /usr/local/plan9/src/cmd/sha1sum.c

     SEE ALSO
          cmp(1), wc(1)

     Page 1                       Plan 9            (printed 10/24/25)