Checksum and count the blocks in a file.

With no FILE, or when FILE is -, read standard input.

Usage: sum [OPTION]... [FILE]...

Options:
  -r             use the BSD sum algorithm, use 1K blocks (default)
  -s, --sysv     use System V sum algorithm, use 512 bytes blocks
  -h, --help     Print help
  -V, --version  Print version