sum — Compute and Check .
sum computes a 16-Bit checksum for each given file(s)/stdin. By default, it computes checksums using an algorithm compatible with BSD sum and prints file sizes in units of 1024-byte blocks.
$ sum file — Print checksum and block counts.
$ sum file1 file2 — Print checksum, block counts and filename.
$ sum -r file — Default. Use BSD sum algorithm (1KB/Block).
$ sum -s file — Use System V sum algorithm (512 bytes/Block).
Read: man sum