为了澄清一些问题：

由于jro有mentioned，正确的方法是使用subprocess.communicate。

然而，当使用带有input的subprocess.communicate来馈送stdin时，需要根据docs来启动带有stdin=subprocess.PIPE的子进程。Note that if you want to send data to the process’s stdin, you need to create the Popen object with stdin=PIPE. Similarly, to get anything other than None in the result tuple, you need to give stdout=PIPE and/or stderr=PIPE too.

还有qed在注释中提到，对于Python 3.4，您需要对字符串进行编码，这意味着您需要将字节传递给input，而不是string。这并不完全正确。根据文档，如果流是以文本模式打开的，则输入应该是字符串(源是同一页)。If streams were opened in text mode, input must be a string. Otherwise, it must be bytes.

因此，如果流不是在文本模式下显式打开的，则应该执行以下操作：import subprocess

command = ['myapp', '--arg1', 'value_for_arg1']

p = subprocess.Popen(command, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)

output = p.communicate(input='some data'.encode())[0]

我特意把上面的stderr值留作STDOUT示例。

也就是说，有时您可能需要另一个进程的输出，而不是从头开始构建它。假设您希望运行与echo -n 'CATCH\nme' | grep -i catch | wc -m等价的代码。这通常会返回“CATCH”中的数字字符和换行符，结果是6。回声的作用是将CATCH\nme数据馈送给grep。因此，我们可以用Python子进程链中的stdin作为变量将数据馈送给grep，然后将stdout作为管道传递给wc进程的stdin(同时，去掉多余的换行符)：import subprocess

what_to_catch = 'catch'

what_to_feed = 'CATCH\nme'

# We create the first subprocess, note that we need stdin=PIPE and stdout=PIPE

p1 = subprocess.Popen(['grep', '-i', what_to_catch], stdin=subprocess.PIPE, stdout=subprocess.PIPE)

# We immediately run the first subprocess and get the result

# Note that we encode the data, otherwise we'd get a TypeError

p1_out = p1.communicate(input=what_to_feed.encode())[0]

# Well the result includes an '\n' at the end,

# if we want to get rid of it in a VERY hacky way

p1_out = p1_out.decode().strip().encode()

# We create the second subprocess, note that we need stdin=PIPE

p2 = subprocess.Popen(['wc', '-m'], stdin=subprocess.PIPE, stdout=subprocess.PIPE)

# We run the second subprocess feeding it with the first subprocess' output.

# We decode the output to convert to a string

# We still have a '\n', so we strip that out

output = p2.communicate(input=p1_out)[0].decode().strip()

这与响应here有些不同，在响应中，您可以直接对两个进程进行管道传输，而无需在Python中直接添加数据。

希望能帮上忙。