Step 2: The user needs to open SHA256SUM.txt manually.
the above picture
Step 3: Then user needs to delete unnecessary part by themself.

3895×231 38.8 KB

Here is my code:

gingshow/SHA256SUM-Checker-for-Windows/blob/master/dist/hash.py

import os
from termcolor import colored
import subprocess
if os.path.isfile('./sha256sum.txt'):

print("file exists")

file = open("sha256sum.txt", "r")
elif os.path.isfile('./SHA256SUMS.txt'):

os.rename('SHA256SUMS.txt', 'sha256sum.txt')

print("file exists")

file = open("sha256sum.txt", "r")
elif os.path.isfile('./sha256.txt'):

os.rename('sha256.txt', 'sha256sum.txt')

print("file exists")

file = open("sha256sum.txt", "r")
else:

print("sha256sum.txt not found")

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Thank you very much.

Thank you for your suggestion!
I made a new one.
Here is the source code.

gingshow/SHA256SUM-Checker-for-Windows/blob/acd4ed46cb6fa078fba2a87dd8f1e616520a46e4/dist/hash.py

import os
from termcolor import colored
import subprocess
hash1=""

hash2=""
if os.path.isfile('./sha256sum.txt'):

print("sha256sum.txt exists")

file1=open("sha256sum.txt","r")

else:

print("sha256sum.txt does not exists,please make sure your file name is correct")

input("Press enter to exit")

exit(0)
if os.path.isfile('./sha256sum2.txt'):

file2 = open("sha256sum2.txt", "w")

file3 = open("sha256sum3.txt", "w")

else:

print("sha256sum2.txt not exists.Creating it")

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I’m sorry to say, but that won’t work at all: The code now checks if the hash entered by the user is the same as the last hash in the sha256sum.txt file, the hash of the actual file is ignored completely. And the two additional files are not needed at all, you should use variables to store data you will need later. And the point of reading the checksum file is that you don’t need to ask the user for a hash.

What I meant is to use a regular expression (using Python module re) to split each line in the sha256sum.txt file in its parts: The checksum and the filename. Something like this:

import re
r = re.compile(r'(^[0-9A-Fa-f]+)\s+(\S.*)$')
with open('sha256sum.txt') as fh:
    for line in fh:
        m = r.match(line)
        if m:
            checksum = m.group(1)
            filename = m.group(2)
            # compare here

Then for each filename check if the checksum matches the actual content. No need to ask the user for anything. If there’s anything unclear, feel free to ask! 🙂

I couldn’t resist completing the example above myself, if you’d like to see the result look here:

https://gist.github.com/airtower-luna/a5df5d6143c8e9ffe7eb5deb5797a0e0

sha256check.py

#!/usr/bin/python3
# Example of how to verify an SHA-256 checksum file using Python.
# Usage: python sha256check.py sha256sum.txt
import hashlib
import re
import sys
This regular expression matches a line containing a hexadecimal
hash, spaces, and a filename. Parentheses create capturing groups.
r = re.compile(r'(^[0-9A-Fa-f]+)\s+(\S.*)$')

Hi airtower-luna when I executed your code. It got an error. Why is this happened?

line 30, in
with open(sys.argv[1]) as fh:
IndexError: list index out of range

I did some edited on my code according to your example code. Now my program can read the checksum file without asking the user for a hash.

gingshow/SHA256SUM-Checker-for-Windows/blob/e780f788ea56aad76e7213fa71dc96cb58ce033e/dist/hash.py

import os
import termcolor
import subprocess
import hashlib
hash1=""

hash2=""
if os.path.isfile('./sha256sum.txt'):

print("sha256sum.txt exists")

else:

print("sha256sum.txt does not exists,please make sure your file name is correct")

input("Press enter to exit")

exit(0)
if os.path.isfile('./sha256sum2.txt'):

file2 = open("sha256sum2.txt", "w")

file3 = open("sha256sum3.txt", "w")

else:

print("sha256sum2.txt not exists.Creating it")

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It got an error. Why is this happened?

line 30, in
with open(sys.argv[1]) as fh:
IndexError: list index out of range

My script expects the name of the checksum file on the command line, instead of requiring it to be named sha256sum.txt. sys.argv (link goes to official Python documentation) is the list of command line arguments, starting with the name of the script itself. If there is no command line argument the list has no element 1, so the access fails.

You could replace the sys.argv[1] with 'sha256sum.txt' to use the same fixed name as in your script, but I prefer the flexibility. People can use different names for their checksum files after all. In a script that’s more than an example I’d check if there is an argument and write an error message saying how you should call the script if not, maybe like this:

if len(sys.argv) < 2:
    print('Missing argument, you need to provide a checksum file!', file=sys.stderr)
    print(f'Usage: {sys.argv[0]} CHECKSUM_FILE', file=sys.stderr)
    sys.exit(1)
with open(sys.argv[1]) as fh:

# ... (as before)

There are a lot more possible error conditions, e.g the file might not exist or not have the right format.

As for the latest version of your script, the biggest issue is that it creates two new files (sha256sum2.txt and sha256sum3.txt) in the current directory. You don’t need those files, just keep the hashes in variables and compare them directly.

And in situations where you really need a file to store intermediate data, use a temporary file. Python has the tempfile module to make that easy, including automatically deleting them on close().

Hey airtower-luna! Thank you very much.
This is my newest version of my script.

gingshow/SHA256-Checker/blob/8ffdfd5da76ecfe88e8537f4c305b1175300329a/dist/hash.py

import os
import hashlib
hash1=""

hash2=""
if os.path.isfile('./sha256sum.txt'):

print("sha256sum.txt exists")

file1 = open("sha256sum.txt", "r")

else:

print("sha256sum.txt does not exists,please make sure your file name is correct")

input("Press enter to exit")

exit(0)
#Display list of files inside directory

print("Display list of files:")

for x in os.listdir('.'):

print(x)
filename = input("Please enter the file name: ")

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Nice, those extra files are gone now. 🙂

From a user point of view I’d still wonder why you need to ask for a filename when all the names are right there in the checksum file.

From my technical point of view I’m wondering: Why aren’t you using regular expressions to read the checksum file? 🐱

Thank you 😀

Q: From a user point of view I’d still wonder why you need to ask for a filename when all the names are right there in the checksum file.
A: The purpose of asking filename is I want the user have a choice to choose the file they want to check rather than the program get the check file for the user. 😁

Q: From my technical point of view I’m wondering: Why aren’t you using regular expressions to read the checksum file?
A: First,I haven’t learn how to use regular expressions. I will learn it later. :face_with_hand_over_mouth:
Therefore, I choose another way, by reading the checksum file line by line, then the program can get the filename input from the user.
After this the program will delete the filename, whitespaces and * from the checksum file. Then the program store those information into the variable without editing the originally checksum file. Finally, the program will check and compare the hash for the user.

This is my new SHA256-Checker repository location. Thank you!

gingshow/SHA256-Checker

A simply SHA256-Checker written in Python. Contribute to gingshow/SHA256-Checker development by creating an account on GitHub.

First,I haven’t learn how to use regular expressions. I will learn it later. :face_with_hand_over_mouth:

Valid! 😄 I’d still recommend learning about them soon, they’re extremely useful for a lot of common programming problems, and this would be a good opportunity.

And I still think it’d be much more user-friendly to just verify all files listed in the checksum file than asking the user to type one of them. 😉