python如何每天在指定时间段运行程序及关闭程序

from datetime import datetime, time
import multiprocessing
from time import sleep
# 程序运行时间在白天8:30 到 15:30  晚上20:30 到 凌晨 2:30
DAY_START = time(8, 30)
DAY_END = time(15, 30)
NIGHT_START = time(20, 30)
NIGHT_END = time(2, 30)
def run_child():
    while 1:
        print("正在运行子进程")
def run_parent():
    print("启动父进程")
    child_process = None  # 是否存在子进程
    while True:
        current_time = datetime.now().time()
        running = False  # 子进程是否可运行
        if DAY_START <= current_time <= DAY_END or (current_time >= NIGHT_START) or (current_time <= NIGHT_END):
            # 判断时候在可运行时间内
            running = True
        # 在时间段内则开启子进程
        if running and child_process is None:
            print("启动子进程")
            child_process = multiprocessing.Process(target=run_child)
            child_process.start()
            print("子进程启动成功")
        # 非记录时间则退出子进程
        if not running and child_process is not None:
            print("关闭子进程")
            child_process.terminate()
            child_process.join()
            child_process = None
            print("子进程关闭成功")
        sleep(5)
if __name__ == '__main__':
    run_parent()

import os
import time
def print_ts(message):
    print "[%s] %s"%(time.strftime("%Y-%m-%d %H:%M:%S", time.localtime()), message)
def run(interval, command):
    print_ts("-"*100)
    print_ts("Command %s"%command)
    print_ts("Starting every %s seconds."%interval)
    print_ts("-"*100)
    while True:
        try:
            # sleep for the remaining seconds of interval
            time_remaining = interval-time.time()%interval
            print_ts("Sleeping until %s (%s seconds)..."%((time.ctime(time.time()+time_remaining)), time_remaining))
            time.sleep(time_remaining)
            print_ts("Starting command.")
            # execute the command
            status = os.system(command)
            print_ts("-"*100)
            print_ts("Command status = %s."%status)
        except Exception, e:
            print e
if __name__=="__main__":
    interval = 5
    command = r"ls"
    run(interval, command)