如何隐藏子流程的输出并继续执行脚本？

Question

How do I start a subprocess or run a python file that has a continuous stream of output and simultaneously run the rest of the script?

here is some example code:

import subprocess

p = subprocess.Popen('python myScript.py', shell=True, stdout=subprocess.PIPE)

#this program will have a stream of output and is designed to run for
#long periods of time

print 'the program is still running!'

doMoreStuff()

Answer 1

在示例代码中调用subprocess.Popen（）之后，主进程将立即进入print（）语句，然后执行doMoreStuff（），同时运行其余脚本。

Answer 2

If you want the program to be silent, you need to capture stderr as well as stdout . Two choices are stderr=subprocess.STDOUT meaning you want to interleave stdout and err on the stdout pipe. Or stderr=subprocess.PIPE to keep stderr distinct.

But you have a second problem. Because you don't read stdout , if the program outputs enough data to fill the pipe it will hang. There is a potential third problem - somewhere along the line you need to call p.wait() so that you don't end up with zombie processes.

You could send them to a file:

proc = subprocess.Popen('python myScript.py', shell=True, 
    stdout=open('stdout.txt', 'wb'), stderr=open('stderr.txt', 'wb'))

Or have background threads do the work:

def out_err_thread(out_err_list, proc):
    out, err = proc.communicate()

proc = subprocess.Popen('python myScript.py', shell=True, 
    stdout=subprocess.PIPE, stderr=subprocess.PIPE)

out_err = []
_t = threading.Thread(target=out_err_thread, args=(out_err, proc))
_t.start()

Or send them to the bit bucket

proc = subprocess.Popen('python myScript.py', shell=True, 
    stdout=open(os.devnull, 'wb'), stderr=subprocess.STDOUT)