ultrix man page for sum

sum(1)							      General Commands Manual							    sum(1)

Name
       sum - print object file's checksum

Syntax
       sum file...

Description
       The  command 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.

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

See Also
       wc(1)

																	    sum(1)