Pexpect 是一個自動控制的 Python 模組,可以用來ssh、ftp、passwd、telnet 等命令列進行自動互動。
官方網站是 http://www.noah.org/
通過它，可以實現類似 expect 的操作。
例如我們可以用它來寫python指令碼，實現批量對一系列（大量的、配置相同的）的linux伺服器進行操作。

一、安裝方式
以root使用者依次執行如下命令：
 wget http://pexpect.sourceforge.net/pexpect-2.3.tar.gz
 tar xzf pexpect-2.3.tar.gz
 cd pexpect-2.3
 sudo python ./setup.py install

二、簡單測試

編寫一個簡單的指令碼pexpect_test.py測試一下

1. #!/usr/bin/env python
2. # -*- coding: utf-8 -*-
3. # filename: pexpect_test.py
4. ''''' 
5. Created on 2010-7-2 
6. @author: forever 
7. '''
8. import pexpect  
9. if __name__ == '__main__':  
10.     user = 'forever'
11.     ip = '192.168.0.200'
12.     mypassword = 'forever'
13.     print user  
14.     child = pexpect.spawn('ssh %
    [email protected]%s' % (user,ip))  
15.     child.expect ('password:')  
16.     child.sendline (mypassword)  
17.     child.expect('$')  
18.     child.sendline('sudo -s')  
19.     child.expect (':')  
20.     child.sendline (mypassword)  
21.     child.expect('#')  
22.     child.sendline('ls -la')  
23.     child.expect('#')  
24.     print child.before   # Print the result of the ls command.
25.     child.sendline("echo '112' >> /home/forever/1.txt ")  
26.     child.interact()     # Give control of the child to the user.
27.     pass

 如果執行命令中有 (>, |, or *) 的操作， 需要用以下形式

shell_cmd = 'ls -l | grep LOG > log_list.txt'
child = pexpect.spawn('/bin/bash', ['-c', shell_cmd])

class spawn(object)  def __init__(self, command, args=[], timeout=30, maxread=2000, searchwindowsize=None, logfile=None, cwd=None, env=None) 
This is the constructor. The command parameter may be a string that includes a command and any arguments to the command. For example:
child = pexpect.spawn ('/usr/bin/ftp')
child = pexpect.spawn ('/usr/bin/ssh [email protected]')
child = pexpect.spawn ('ls -latr /tmp')
You may also construct it with a list of arguments like so:
child = pexpect.spawn ('/usr/bin/ftp', [])
child = pexpect.spawn ('/usr/bin/ssh', ['[email protected]'])
child = pexpect.spawn ('ls', ['-latr', '/tmp'])

After this the child application will be created and will be ready to talk to. For normal use, see expect() and send() and sendline().
Remember that Pexpect does NOT interpret shell meta characters such as redirect, pipe, or wild cards (>, |, or *). This is a common mistake. If you want to run a command and pipe it through another command then you must also start a shell. For example:
child = pexpect.spawn('/bin/bash -c "ls -l | grep LOG > log_list.txt"')
child.expect(pexpect.EOF)

The second form of spawn (where you pass a list of arguments) is useful in situations where you wish to spawn a command and pass it its own argument list. This can make syntax more clear. For example, the following is equivalent to the previous example:
shell_cmd = 'ls -l | grep LOG > log_list.txt'
child = pexpect.spawn('/bin/bash', ['-c', shell_cmd])
child.expect(pexpect.EOF)