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

from subprocess import Popen, PIPE
from tempfile import SpooledTemporaryFile as tempfile
f = tempfile()
f.write('one\ntwo\nthree\nfour\nfive\nsix\n')
f.seek(0)
print Popen(['/bin/grep','f'],stdout=PIPE,stdin=f).stdout.read()
f.close()

2012-04-13 03:36:37

其他回答

"""
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

p = Popen(['grep', 'f'], stdout=PIPE, stdin=PIPE, stderr=STDOUT)    
p.stdin.write('one\n')
time.sleep(0.5)
p.stdin.write('two\n')
time.sleep(0.5)
p.stdin.write('three\n')
time.sleep(0.5)
testresult = p.communicate()[0]
time.sleep(0.5)
print(testresult)

2009-04-09 04:39:40

如果您使用的是Python 3.4或更高版本，那么有一个很好的解决方案。使用input参数而不是stdin参数，它接受bytes参数:

output_bytes = subprocess.check_output(
    ["sed", "s/foo/bar/"],
    input=b"foo",
)

这适用于check_output和run，但不适用于call或check_call。

在Python 3.7+中，你还可以添加text=True，使check_output接受一个字符串作为输入并返回一个字符串(而不是字节):

output_string = subprocess.check_output(
    ["sed", "s/foo/bar/"],
    input="foo",
    text=True,
)

2016-12-08 10:04:26

在Python 3.7+上这样做:

my_data = "whatever you want\nshould match this f"
subprocess.run(["grep", "f"], text=True, input=my_data)

并且您可能希望添加capture_output=True以获得以字符串形式运行命令的输出。

在旧版本的Python中，将text=True替换为universal_newlines=True:

subprocess.run(["grep", "f"], universal_newlines=True, input=my_data)

2019-12-27 04:29:04

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

我如何传递一个字符串到子进程。Popen(使用stdin参数)?

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