A simple SHA256 hashing example, written in Python using hashlib

generate_data.sh

#!/bin/bash
# Generates ten data files, each 300 MB in size and filled with random data.

[[ ! -d "data/" ]] && mkdir "data/"

for i in {1..10}; do
    dd if="/dev/random" of="data/file${i}" bs=1m count=300
done

sha256.py

#!/usr/bin/env python

import hashlib
import sys

def sha256_checksum(filename, block_size=65536):
    sha256 = hashlib.sha256()
    with open(filename, 'rb') as f:
        for block in iter(lambda: f.read(block_size), b''):
            sha256.update(block)
    return sha256.hexdigest()

def main():
    for f in sys.argv[1:]:
        checksum = sha256_checksum(f)
        print(f + '\t' + checksum)

if __name__ == '__main__':
    main()