Python利用subprocess起进程

from multiprocessing import Process, Pool
import time
import subprocess

def task(msg):
    print 'hello, %s' % msg
    time.sleep(1)

def test_pool():
    pool = Pool(processes=4)
    for x in range(10):
        pool.apply_async(task, args=(x,))
    print "for end"

    pool.close()
    print "pool close"

    pool.join()
    print "pool join"

    print 'processes done.'

def test_process():
    p = Process(target=task, args=(command,))
    p.start()
    p.join()

if __name__ == '__main__':
    test_pool()