compare-lists.py - Compares 2 lists aka items that appear in one list but do not show up in the second list

compare-lists.py

#!/usr/bin/env python3
import os
import sys
import argparse

parser = argparse.ArgumentParser(description="Compare 2 lists - Finds items in list1, not present in list2")
parser.add_argument("-l1", "--list1", dest="list1", action="store", required=True,
                    help="list1")
parser.add_argument("-l2", "--list2", dest="list2", action="store", required=True,
                    help="list2")
parser.add_argument("-c", "--case-sensitive-search", dest="case_sensitive_search", action="store_true",
                    help="Case sensitive search")
args = parser.parse_args()
list1 = args.list1
list2 = args.list2
case_sensitive_search = args.case_sensitive_search

if not os.path.isfile(list1):
    print("[-] list1: {} not found".format(list1))
    sys.exit(1)

if not os.path.isfile(list2):
    print("[-] list2: {} not found".format(list2))
    sys.exit(1)

if not case_sensitive_search:
    with open(list2, "r+") as f:
        list2_contents = f.read()

    with open(list1, "r+") as f:
        with open(list2, "r+") as f2:
            for line1 in f:
                line1_nws = line1.strip()
                line1_found_in_file2 = False
                for line2 in f2:
                    line2_nws = line2.strip()
                    if line2_nws == line1_nws:
                        line1_found_in_file2 = True
                        break
                if not line1_found_in_file2:
                    print(line1_nws)