.TH SUM 1 .SH NAME sum \- sum and count blocks in a file .SH SYNOPSIS .B sum file .SH DESCRIPTION .I Sum calculates and prints a 16-bit checksum for the named file, and also prints the number of blocks in the file. It is typically used to look for bad spots, or to validate a file communicated over some transmission line. .SH "SEE ALSO" wc(1) .SH DIAGNOSTICS `Read error' is indistinuishable from end of file on most devices; check the block count.