multiprocessing_write.py

import os
import sys


def main():
    line = 'x' * (int(sys.argv[1]) - 1) + '\n'
    buf_mode = {'--nbf': 0, '--lbf': 1, '--fbf': 2}[sys.argv[2]]

    for _ in range(10):
        pid = os.fork()
        if pid == 0:
            record(line, buf_mode)
            sys.exit()
        else:
            continue
    for _ in range(10):
        os.wait()


def record(line, buf_mode):
    with open('./out.txt', 'a', buffering=buf_mode) as f:
        for _ in range(1000):
            f.write(line)


if __name__ == '__main__':
    main()