使用Expect SSH来服务器和执行命令 [英] Using expect to SSH to server and execute commands

问题描述

我想编写一个通用的Expect脚本，以通过SSH登录到系统并执行一些命令.我发现一个示例具有以下内容:

I want to write a generic expect script to login through SSH to a system and execute some commands. An example I found had the following:

#!/usr/bin/expect

set fid [open ./.secret]
set password [read $fid]
close $fid
spawn /usr/bin/ssh root@[lindex $argv 0]
expect {
  -re ".*Are.*.*yes.*no.*" {
    send "yes\n"
    exp_continue
    #look for the password prompt
  }

  "*?assword:*" {
    send $password
    send "\n"
  }
}

send -- "PS1='>'\r"
expect -re ">$" { send "hostname\r" }
expect -re ">$" { send "pwd\r" }

...该脚本似乎已正确登录，但未执行最后2个发送.想法?

...the script seems to login properly but it didn't execute the last 2 sends. Ideas?

启用exp_internal后，我注意到以下内容:

After enabling exp_internal, I noticed the following:

expect: does "" (spawn_id exp4) match glob pattern "*"? yes
expect: set expect_out(0,string) ""
expect: set expect_out(spawn_id) "exp4"
expect: set expect_out(buffer) ""
send: sending "PS1='>'\r" to { exp4 }
Gate keeper glob pattern for '>$' is '>'. Activating booster.

expect: does "" (spawn_id exp4) match regular expression ">$"? Gate ">"? gate=no


expect: does "\r\n" (spawn_id exp4) match regular expression ">$"? Gate ">"? gate=no
Last login: Tue Nov  6 14:13:31 2012 from 1.x.x.x

expect: does "\r\nLast login: Tue Nov  6 14:13:31 2012 from 1.x.x.x\r\r\n" (spawn_id exp4) match regular expression ">$"? Gate ">"? gate=no

我正在尝试发送PS1='>'\r，因为我想覆盖提示.我认为我无法预测提示会是什么，因此，我不知道会出现什么模式.从上面看来，提示未更改.您如何解决这样的问题?

I'm trying to send PS1='>'\r because I want to override the prompt. I don't think there's any way for me to predict what the prompt will be and therefore, I wouldn't know what pattern to expect. From the above, it looks like the prompt wasn't changed. How do you tackle a problem like this?

推荐答案

您的脚本似乎没有什么很明显错误(尽管使用其他提示可能使匹配容易一些) .这意味着它有些微妙.我建议添加以下内容:

There doesn't appear to be anything obviously wrong with your script (though using a different prompt might make matching a bit easier). Which means it is something subtle. I suggest adding this:

exp_debug 1

到脚本中的早期位置.它将使Expect引擎更多地打印 lot 关于它在做什么的信息，这(可能)可以帮助您了解问题所在，或者失败了，这会帮助此处的人帮助您……

to somewhere early in your script. It will make the Expect engine print a lot more about what it is doing, which will (probably) help you understand what is going wrong, or failing that help the people here help you…

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