random_id_generator.py

import uuid
import csv

def my_random_string(string_length=10):
    """Returns a random string of length string_length."""
    random = str(uuid.uuid4())  # Convert UUID format to a Python string.
    random = random.upper()  # Make all characters uppercase.
    random = random.replace("-", "")  # Remove the UUID '-'.
    return random[0:string_length]  # Return the random string.


# print(my_random_string(8))  # For example, D9E50C

ids = set()
while len(ids) < 2000000:
    ids.add(my_random_string(8))

cw = csv.writer(open("hello.csv", 'w'))
cw.writerows([c.strip() for c in r.strip(', ').split(',')]
             for r in list(ids))

find and print duplicate rows in perl: perl -ne 'print if $SEEN{$_}++' < input-file