File Hash Calculator
This utility calculates the MD5, SHA1, and SHA256 hashes of a given file. It reads the file in binary mode and processes it in chunks, ensuring it can handle large files without using excessive memory.
Modules Used:
- hashlib: To calculate secure hashes and message digests.
- argparse: To handle command-line arguments.
The Code
Save this as hasher.py.
import hashlib
import argparse
import sys
import os
def calculate_hashes(file_path):
if not os.path.exists(file_path):
print(f"Error: File '{file_path}' not found.")
return
# Initialize hash objects
md5 = hashlib.md5()
sha1 = hashlib.sha1()
sha256 = hashlib.sha256()
print(f"Calculating hashes for '{file_path}'...")
try:
with open(file_path, 'rb') as f:
# Read in chunks (e.g., 64KB) to handle large files efficiently
while True:
chunk = f.read(65536)
if not chunk:
break
# Update all hashers with the chunk
md5.update(chunk)
sha1.update(chunk)
sha256.update(chunk)
print("-" * 70)
print(f"{'Algorithm':<10} | {'Hash'}")
print("-" * 70)
print(f"{'MD5':<10} | {md5.hexdigest()}")
print(f"{'SHA1':<10} | {sha1.hexdigest()}")
print(f"{'SHA256':<10} | {sha256.hexdigest()}")
print("-" * 70)
except PermissionError:
print(f"Error: Permission denied reading '{file_path}'.")
except Exception as e:
print(f"An error occurred: {e}")
if __name__ == "__main__":
parser = argparse.ArgumentParser(description="File Hash Calculator")
parser.add_argument("file", help="Path to the file")
args = parser.parse_args()
calculate_hashes(args.file)Usage
python hasher.py my_installer.exe