从bash捕获telnet超时 [英] Capturing telnet timeout from bash

问题描述

引用此问题:使用bash脚本自动进行telnet会话

我正在尝试捕获远程主机超时所花费的时间.假设是10秒.手动，我可以启动 time telnet主机端口输入一些命令，然后不执行任何操作，并且在10秒钟后， time 的输出将保存我所需的时间.

I am trying to capture the time it takes for a remote host to timeout. Let's say it's 10 seconds. By hand, I can launch time telnet host port input some commands and then do nothing and after 10 seconds time's output will hold my needed time.

在脚本中，问题在于使用此解决方案:

While, in a script, the issue is that using this solution:

{ echo "command"; } | time telnet host port

当管道结束时，它将发送EOF，并且telnet立即关闭.我可以通过添加一个 n 作为我的最后一个管道命令来解决此问题，但是随后所有内容都将在该超时时间内挂起(这可能比实际服务器超时还要长).

when the pipes end, it sends an EOF and telnet closes immediately. I can solve this by adding a sleep n as my last piped command, but then everything hangs for that timeout (which can be more than the actual server timeout).

仅说明一下我要做什么，所以让我们借用Google的帮助.我希望我的时间输出为5分钟，这就是Google似乎用作超时的时间.相反:

Just to explain what I'm trying to do let's borrow Google's help. I want my time output to be 5 minutes, which is what Google seems to use as timeout. Instead:

{ echo "GET / HTTP/1.1"; echo "Host: www.google.com"; echo "Connection: keep-Alive"; echo ""; echo ""; } | time telnet www.google.com 80 2>&1

给出 0 -错误(立即发送EOF)

Gives 0 - wrong (EOF is sent immediately)

{ echo "GET / HTTP/1.1"; echo "Host: www.google.com"; echo "Connection: keep-Alive"; echo ""; echo ""; sleep 10; } | time telnet www.google.com 80 2>&1

给出 10 -错误

{ echo "GET / HTTP/1.1"; echo "Host: www.google.com"; echo "Connection: keep-Alive"; echo ""; echo ""; sleep 1; } | time telnet www.google.com 80 2>&1

给出 1 -错误

{ echo "GET / HTTP/1.1"; echo "Host: www.google.com"; echo "Connection: keep-Alive"; echo ""; echo ""; sleep 900; } | time telnet www.google.com 80 2>&1

给出 900 -错误(在这里，如果远程主机发送了kill命令，那么我希望telnet停止，但是睡眠会获胜)

Gives 900 - wrong (here I would expect the telnet to stop given the remote host sends a kill, but instead the sleep wins)

那么，我该如何解决呢?谢谢！

So, how can I solve this? Thanks!

推荐答案

尽管我不太喜欢它，但这似乎可行:

Although I don't overly like it, this seems to work:

( time { echo "set timeout 400"; echo "spawn telnet www.google.com 80"; 
         echo 'send "GET / HTTP/1.1\r"'; echo "send \"Host: www.google.com\r\""; 
         echo 'send "Connection: keep-alive\r"'; echo 'send "\r"'; 
         echo "expect { eof exit timeout exit }"; } | expect ) 2>&1

上面的代码同时输出HTTP标头/正文和时间结果，因此都可以对其进行操作.

The above outputs both the HTTP headers/body and the time results, so both can be manipulated.

顺便说一句，以上内容适用于HTTP.对于HTTPS，您必须使用openssl，但是可以使用相同的系统.

By the way, the above works for HTTP. For HTTPS you have to use openssl, but the same system works.

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