pexpect学习阶段

　　网上关于pexpect的介绍基本都类似于这样http://blog.csdn.net/sdustliyang/article/details/23373485，但是并没有关于下述问题的解释

　　问题：可以ssh到主机，但是后面执行的命令无法生效

　　代码如下：

 1 import pexpect
 2 import sys
 3
 4 child = pexpect.spawn(‘ssh [email protected]‘)
 5 fout = file(‘mylog.txt‘,‘w‘)
 6 child.logfile = fout
 7
 8 child.expect(‘password:‘)
 9 child.sendline(‘mypassword‘)
10
11 child.expect(‘#‘)
12 child.sendline(‘ls /home‘)
14 child.expect(‘#‘)

日志信息：

[email protected]‘s password: mypassword

  ######################################################################
  #                              Notice                                #
  #                                                                    #
  #  1. Please DO NOT upgrade the kernel, as the kernel upgrade would  #
  #   damage the original operating system.                            #
  #                                                                    #
  #  2. Please create unique passwords that use a combination of words,#
  #   numbers, symbols, and both upper-case and lower-case letters.    #
  #   Avoid using simple adjacent keyboard combinations such as        #
  #   "Qwert!234","Qaz2wsx",etc.                                       #
  #                                                                    #
  #  3. Unless necessary, please DO NOT open or use high-risk ports,   #
  #   such as Telnet-23, FTP-20/21, NTP-123(UDP), RDP-3389,            #
  #   SSH/SFTP-22, Mysql-3306, SQL-1433,etc.                           #
  #                                                                    #
  #                     Any questions please contact 4000-955-988      #
  ######################################################################
ls /home

可以看到ssh是成功连接的，但是ls /home命令并没有执行。什么原因呐？我也不知道....网上也找不到