import re
import sys
import os

logz = [fn for fn in os.listdir(r'my text file directory') if fn.endswith('.txt')]

err_occur = [] # The list where we will store results.
pattern = re.compile(" error ", re.IGNORECASE)


try: # Try to:
    with open ('logz', 'rt') as in_file: # open file for reading text.
        for linenum, line in enumerate(in_file):
            if pattern.search(line) != None:
                err_occur.append((linenum, line.rstrip('/n')))
                print("Line ", linenum, ": ", line, sep='')

import pathlib


def main():
    for path in pathlib.Path('.').iterdir():
        if path.suffix.lower() == '.txt':
            with path.open() as file:
                for line, text in enumerate(file):
                    if 'error' in text.lower():
                        print(f'Line {line}: {text}')


if __name__ == '__main__':
    main()