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?
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)
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.
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)
