Generating one MD5/SHA1 checksum of multiple files in Python

Question

I have looked through several topics about calculating checksums of files in Python but none of them answered the question about one sum from multiple files. I have several files in sub directories and would like to determine if there was any change in one or more of them.
Is there a way to generate one sum from multiple files?

EDIT:
This is the way I do it to get a list of sums:

checksums = [(fname, hashlib.md5(open(fname, 'rb').read()).digest()) for fname in flist]

Asked By: Artur

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Source

Answer 1

So I made it 🙂 This way one hash sum is generated for a file list.

hash_obj = hashlib.md5(open(flist[0], 'rb').read())
for fname in flist[1:]:
    hash_obj.update(open(fname, 'rb').read())
checksum = hash_obj.digest()

Thank you PM 2Ring for your input!

Note that md5 has been cracked so use it only for non security critical purposes.

Answered By: Artur

Answer 2

Slightly cleaner than Artur’s answer. There’s no need to treat the first element specially.

Edit (2022): I know Python a bit better now so I updated the code as follows:

Use pathlib – it’s more ergonomic and doesn’t leave files open.
Add type hints. If you don’t use these you’re doing it wrong.
Avoid a very mild TOCTOU issue.

import hashlib
from pathlib import Path

def calculate_checksum(filenames: list[str]) -> bytes:
    hash = hashlib.md5()
    for fn in filenames:
        try:
            hash.update(Path(fn).read_bytes())
        except IsADirectoryError:
            pass
    return hash.digest()

(You can handle IsADirectoryError differently if you like.)

Answered By: Timmmm

Answer 3

import subprocess
cmd =input("Enter the command : ")
trial = subprocess.run(["powershell","-Command",cmd])
#Powershell command : Get-FileHash -Algorithm MD5 -Path (Get-ChildItem "filepath*.*" -Recurse -force)

Answered By: Safeer M

Generating one MD5/SHA1 checksum of multiple files in Python

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