我如何传递一个字符串到子进程。Popen(使用stdin参数)?

如果我这样做:

import subprocess
from cStringIO import StringIO
subprocess.Popen(['grep','f'],stdout=subprocess.PIPE,stdin=StringIO('one\ntwo\nthree\nfour\nfive\nsix\n')).communicate()[0]

我得到:

Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "/build/toolchain/mac32/python-2.4.3/lib/python2.4/subprocess.py", line 533, in __init__
    (p2cread, p2cwrite,
  File "/build/toolchain/mac32/python-2.4.3/lib/python2.4/subprocess.py", line 830, in _get_handles
    p2cread = stdin.fileno()
AttributeError: 'cStringIO.StringI' object has no attribute 'fileno'

显然是cStringIO。StringIO对象的嘎嘎声不够接近文件鸭子，不适合subprocess.Popen。我怎么解决这个问题呢?

当前回答

"""
Ex: Dialog (2-way) with a Popen()
"""

p = subprocess.Popen('Your Command Here',
                 stdout=subprocess.PIPE,
                 stderr=subprocess.STDOUT,
                 stdin=PIPE,
                 shell=True,
                 bufsize=0)
p.stdin.write('START\n')
out = p.stdout.readline()
while out:
  line = out
  line = line.rstrip("\n")

  if "WHATEVER1" in line:
      pr = 1
      p.stdin.write('DO 1\n')
      out = p.stdout.readline()
      continue

  if "WHATEVER2" in line:
      pr = 2
      p.stdin.write('DO 2\n')
      out = p.stdout.readline()
      continue
"""
..........
"""

out = p.stdout.readline()

p.wait()

2013-06-14 13:20:23

其他回答

我想出了一个变通办法:

>>> p = subprocess.Popen(['grep','f'],stdout=subprocess.PIPE,stdin=subprocess.PIPE)
>>> p.stdin.write(b'one\ntwo\nthree\nfour\nfive\nsix\n') #expects a bytes type object
>>> p.communicate()[0]
'four\nfive\n'
>>> p.stdin.close()

还有更好的吗?

2008-10-02 17:27:55

这对于grep来说有点过分了，但是通过我的学习，我已经了解了Linux命令expect和python库pexpect

期望:对话与互动程序 pexpect:用于生成子应用程序的Python模块;控制他们;并在他们的输出中响应预期的模式。

import pexpect
child = pexpect.spawn('grep f', timeout=10)
child.sendline('text to match')
print(child.before)

使用pexpect使用交互式shell应用程序(如ftp)非常简单

import pexpect
child = pexpect.spawn ('ftp ftp.openbsd.org')
child.expect ('Name .*: ')
child.sendline ('anonymous')
child.expect ('Password:')
child.sendline ('noah@example.com')
child.expect ('ftp> ')
child.sendline ('ls /pub/OpenBSD/')
child.expect ('ftp> ')
print child.before   # Print the result of the ls command.
child.interact()     # Give control of the child to the user.

2021-03-22 21:35:46

"""
Ex: Dialog (2-way) with a Popen()
"""

p = subprocess.Popen('Your Command Here',
                 stdout=subprocess.PIPE,
                 stderr=subprocess.STDOUT,
                 stdin=PIPE,
                 shell=True,
                 bufsize=0)
p.stdin.write('START\n')
out = p.stdout.readline()
while out:
  line = out
  line = line.rstrip("\n")

  if "WHATEVER1" in line:
      pr = 1
      p.stdin.write('DO 1\n')
      out = p.stdout.readline()
      continue

  if "WHATEVER2" in line:
      pr = 2
      p.stdin.write('DO 2\n')
      out = p.stdout.readline()
      continue
"""
..........
"""

out = p.stdout.readline()

p.wait()

2013-06-14 13:20:23

我使用python3，发现你需要编码你的字符串，然后才能将它传递到stdin:

p = Popen(['grep', 'f'], stdout=PIPE, stdin=PIPE, stderr=PIPE)
out, err = p.communicate(input='one\ntwo\nthree\nfour\nfive\nsix\n'.encode())
print(out)

2014-07-27 15:29:17

显然是cStringIO。StringIO对象的嘎嘎声不够接近适合子进程的文件鸭。Popen

恐怕不行。管道是一个低级的操作系统概念，因此它绝对需要一个由操作系统级文件描述符表示的文件对象。你的解决方法是正确的。

2008-10-02 18:33:23

我如何传递一个字符串到子进程。Popen(使用stdin参数)?

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