bash – 使用expect脚本帮助,在远程comp上运行cat并将其输出到变

我有一个bash expect脚本,它必须通过ssh连接到远程comp,在那里读取文件,找到带有“hostname”的特定行(如“hostname aaaa1111”)并将此主机名存储到while之后要使用的变量中.如何获取“hostname”参数的值？我认为行内容将在$expect_out(缓冲区)变量中(因此我可以扫描并分析),但事实并非如此.我的脚本是：

#!/bin/bash        
    ----bash part----
    /usr/bin/expect << ENDOFEXPECT
    spawn bash -c "ssh root@$IP"  
    expect "password:"
    send "xxxxr"
    expect ":~#"
    send "cat /etc/rc.d/rc.local |grep hostname n"
    expect ":~#"
    set line $expect_out(buffer)
    puts "line = $line,expect_out(buffer) = $expect_out(buffer)"
    ...more script...
    ENDOFEXPECT

这里http://en.wikipedia.org/wiki/Expect有一个例子：

# Send the prebuilt command,and then wait for another shell prompt.
    send "$my_commandr"
    expect "%"
    # Capture the results of the command into a variable. This can be displayed,or written to disk.
    set results $expect_out(buffer)

似乎它在这种情况下不起作用,或者脚本有什么问题？

export IP
/usr/bin/expect << 'ENDOFEXPECT'
  set prompt ":~#"
  spawn ssh root@$env(IP)  
  expect "password:"
  send "xxxxr"
  expect $prompt
  send "grep hostname /etc/rc.d/rc.local n"
  expect $prompt
  set line $expect_out(buffer)
  ...more script...
ENDOFEXPECT