get a sha256 digest of a file using python's hashlib

hashfile.py

""" Hash a file supplied by argv[1] """

from sys import argv
from hashlib import sha256

# Construct an sha256 algorith
h256 = sha256()

# Get the name of the file we want to hash
fname = argv[1]

# Read the contents of the file into the hash algorithm
h256.update(open(fname,'rb').read())

# Print the digest/hash of the file's contents
print (h256.hexdigest())