V8/usr/man/man1/sum.1

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.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
along with the
length (in blocks) 
and name of 
each
.IR file .
If no files are given,
the standard input is
summed.
If
.I file
is `\-',
file names are read from standard input.
.PP
.I Sum
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 indistinguishable from end of file on
most devices; check the byte count.