sum
calculates and displays a 16-bit checksum for the named file,
and also displays the size of the file in kilobytes.
It is typically used to look for bad spots, or
to validate a file communicated over
some transmission line.
The checksum is calculated by an algorithm which may yield different results
on machines with 16-bit
ints
and machines with 32-bit
ints,
so it cannot
always be used to validate that a file
has been transferred between machines
with different-sized
ints.
Diagnostics
Read error
is indistinguishable from
EOF
on most devices; check the block count.