sum(1)

NAME
     sum - print checksum and block count of a file

SYNOPSIS
     sum [ -r ] file

DESCRIPTION
     sum calculates and prints a 16-bit checksum for the named file, and also
     prints the number of blocks in the file.  NULL characters (with ASCII
     value zero) are ignored in computing the checksum.  sum is typically used
     to look for bad spots, or to validate a file communicated over some
     transmission line.  The option -r causes an alternate algorithm to be
     used in computing the checksum.  This alternate algorithm does not ignore
     NULL characters.

SEE ALSO
     wc(1).

DIAGNOSTICS
     ``Read error'' is indistinguishable from end of file on most devices;
     check the block count.