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bash - bash telnet 从期望中获取标准输出

问题描述

我需要从 telnet shell 获取数据集，为此我查看了期望 https://www2.lib.uchicago.edu/keith/tcl-course/topics/expect.html

这是我的期望脚本：

/usr/bin/expect -d <<  EOD
spawn telnet myhost
log_user 1
set timeout 10
expect "Login:"
send "user\n\r"
expect "Password:"
send "password\n\r"
expect "*$*"
send "AT\n\r"
expect "OK"
send "AT&CSR\n"
expect "OK"
send "AT!G=A6\n"
expect "OK"
send "AT^MI=0\n"
expect "OK"
send "AT^SX=0\n"
expect "OK"
send "AT^SR=0,1"
expect "*$*"
send "exit\r"

现在我可以连接到远程主机，发送命令，但无法读取结果，这里是一个 shell 结果：

> 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 "AT\n\r" to { exp4 }
> 
> expect: does "" (spawn_id exp4) match glob pattern "OK"? no
> ********
> 
> OK
> 
> expect: does "********\r\n\r\nOK\r\n" (spawn_id exp4) match glob
> pattern "OK"? yes expect: set expect_out(0,string) "OK" expect: set
> expect_out(spawn_id) "exp4" expect: set expect_out(buffer)
> "********\r\n\r\nOK" send: sending "AT&CSR\n" to { exp4 }
> 
> expect: does "\r\n" (spawn_id exp4) match glob pattern "OK"? no AT
> 
> expect: does "\r\nAT\r\n" (spawn_id exp4) match glob pattern "OK"? no
> 
> OK
> 
> expect: does "\r\nAT\r\n\r\nOK\r\n" (spawn_id exp4) match glob pattern
> "OK"? yes expect: set expect_out(0,string) "OK" expect: set
> expect_out(spawn_id) "exp4" expect: set expect_out(buffer)
> "\r\nAT\r\n\r\nOK" send: sending "AT!G=A6\n" to { exp4 }
> 
> expect: does "\r\n" (spawn_id exp4) match glob pattern "OK"? no AT&CSR
> expect: does "\r\nAT&CSR" (spawn_id exp4) match glob pattern "OK"? no
> AT!G=A6 expect: does "\r\nAT&CSRAT!G=A6" (spawn_id exp4) match glob
> pattern "OK"? no expect: timed out send: sending "AT^MI=0\n" to { exp4
> }
> 
> expect: does "\r\nAT&CSRAT!G=A6" (spawn_id exp4) match glob pattern
> "OK"? no AT^MI=0

如果命令的结果与预期的不匹配，它会转到下一个命令，有没有办法捕捉响应结果？

编辑：
我试图简化事情并添加交互，但没有运气：

 /usr/bin/expect -d <<  EOD
> spawn telnet myhost
> log_user 1
> interact"
> EOD
expect version 5.45.4
argv[0] = /usr/bin/expect  argv[1] = -d  
set argc 0
set argv0 "/usr/bin/expect"
set argv ""
executing commands from command file
spawn telnet myhost
parent: waiting for sync byte
parent: telling child to go ahead
parent: now unsynchronized from child
spawn: returns {11306}
invalid command name "interact""
    while executing
"interact""

标签： bashexpectat-command

解决方案

您发送 AT 命令的方式是错误的。

根据ETSI 规范 127.007，默认情况下 AT 命令以\r(IRA 13 - ASCII 回车) 字符[1]终止。有关详细信息，请参阅段落“4.1 - 命令行”。

为了解决您的问题，只需发送AT\r而不是AT\n\r，AT&CSR\r而不是AT&CSR\n等等（后者是您对每个后续 AT 命令重复的错误）。否则 AT 解析器将无法正确识别您的命令。

[1] 可以通过命令自定义命令行终止ATS3符，语法如下：

ATS3=<value>

哪里<value>是新命令行终止字符的十进制 ASCII 值（默认为 13）。

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