Tcl 循环提示输入另一个密码时出现问题

我需要一些关于EXPECT脚本的帮助

我正在尝试在访问大量主机之前自动登录，并在用户错误输入密码时提供服务。我首先获取用户名和密码，然后针对特定主机进行验证。如果密码无效，我想循环并再次询问用户名和密码

我正在尝试：-

（省略前面几行不相关的内容）

}elseif{[lindex$argv 0]！=“”{

它的行“找不到名为“exp6”的频道”，这是真正困扰我

---

我做错了什么？我正在阅读Exploring Expect（Don line），但却一事无成。

每当

Expect

应该等待某个单词时，它会将该Expect进程的

spawn\u id

保存到

Expect\u out（spawn\u id）

根据您的代码，expect的spawn_id是在遇到

        expect -re "(.*)\n"

当用户键入某个内容并按enter键时，它将保存expect的生成id

expect does "" (spawn_id exp0) match regular expression "(.*)\n" 

假设用户输入了“Simon”，那么调试输出将是

expect: does "Simon\n" (spawn_id exp0) match regular expression "(.*)\n"? Gate "*\n"? gate=yes re=yes
expect: set expect_out(0,string) "Simon\n"
expect: set expect_out(1,string) "Simon"
expect: set expect_out(spawn_id) "exp0"
expect: set expect_out(buffer) "Simon\n"

如您所见，expect_out（spawn_id）包含

spawn_id

，它必须从中期望值。在本例中，术语

exp0

指向标准输入

如果使用了

spawn

命令，那么正如您所知，tcl变量

spawn_id

保存对进程句柄的引用，该进程句柄称为spawn句柄。我们可以通过显式设置进程句柄并将其保存以备将来参考来处理

spawn_id

，这是一个很好的部分

根据您的代码，当以下代码给出错误密码时，您正在关闭ssh连接

close $spawn_id

通过利用

spawn\u id

，您正在这样做，您缺少的是将

expect

的进程句柄设置回其原始引用句柄

While {1} { 

    ###Initial state. Nothing present in spawn_id variable ######
    expect "something here"; #### Now exp0 will be created  

    ###some code here ####

    ##Spawning a process now###

    spawn ssh xyz ##At this moment, spawn_id updated

    ###doing some operations###
    ###closing ssh with some conditions###
    close $spawn_id

    ##Loop is about to end and still spawn_id has the reference to ssh process  
    ###If anything present in that, expect will assume that might be current process
    ###so, it will try to expect from that process

}

当循环第二次执行时，expect将尝试从

spawn\u id

句柄中执行命令，该句柄只不过是ssh进程，这就是您出现错误的原因

can not find channel named "exp6" 

请注意，“exp6”只是ssh进程的spawn句柄

更新：

如果某个进程句柄在

spawn\u id

，则

expect

将始终期待来自该站点的命令 只处理

也许您可以尝试以下方法来避免这些问题

#Some reference variable 
set expect_init_spawn_id 0

while {1} {

    if { $expect_spawn_id !=0 } {
            #when the loop enters from 2nd iteration,
            #spawn_id is explicitly set to initial 'exp0' handle
            set spawn_id $expect_init_spawn_id 
    }

    expect -re "(.*)\n"
    #Saving the init spawn id of expect process
    #And it will have the value as 'exp0'
    set expect_init_spawn_id $expect_out(spawn_id)
    spawn ssh xyz

    ##Manipulations here

    #closing ssh now
    close $spawn_id
}

---

这是我的观点，可能不是有效的方法。你也可以考虑自己的逻辑来处理这些问题。

太棒了！非常清楚的解释，现在一切都有意义了。问题解决了，我可以继续。非常感谢。

While {1} { 

    ###Initial state. Nothing present in spawn_id variable ######
    expect "something here"; #### Now exp0 will be created  

    ###some code here ####

    ##Spawning a process now###

    spawn ssh xyz ##At this moment, spawn_id updated

    ###doing some operations###
    ###closing ssh with some conditions###
    close $spawn_id

    ##Loop is about to end and still spawn_id has the reference to ssh process  
    ###If anything present in that, expect will assume that might be current process
    ###so, it will try to expect from that process

can not find channel named "exp6" 

#Some reference variable 
set expect_init_spawn_id 0

while {1} {

    if { $expect_spawn_id !=0 } {
            #when the loop enters from 2nd iteration,
            #spawn_id is explicitly set to initial 'exp0' handle
            set spawn_id $expect_init_spawn_id 
    }

    expect -re "(.*)\n"
    #Saving the init spawn id of expect process
    #And it will have the value as 'exp0'
    set expect_init_spawn_id $expect_out(spawn_id)
    spawn ssh xyz

    ##Manipulations here

    #closing ssh now
    close $spawn_id
}