为什么我不能使用subprocess.Popen与SSH交互？

Question

I'm trying to interact with SSH using Python's subprocess library. Here's my current code:

import subprocess
import time
proc = subprocess.Popen(["ssh", "-tt", "user@host"],
                        stdout=subprocess.PIPE, stdin=subprocess.PIPE)
time.sleep(10)
proc.stdin.write(b"ls\n")
while True:
    next_line = proc.stdout.readline()
    if next_line != '':
        print(next_line.decode("utf-8"), end='')
    else:
        time.sleep(.01)

When I run it, I get the usual SSH security banner, but nothing else. I log in via public key and have already added the host to my known_hosts list, so I would imagine authentication shouldn't be an issue. By changing ls to a command to write text to a file, I have confirmed that no commands are "going through." What is the problem, and how can I fix it?

Answer 1

You may need to call proc.stdin.flush() . More generally, you should use Paramiko instead, which is a Python library for SSH directly, rather than using Popen for this.