Telnet batch test (II): key codes for the implementation of Telnet batch test script

One 、 introduction

In my last blog, I talked about telnet Elegant stop , That is, through sleep Command to make telnet Command exit , use telnet Judge by the output of the exit telnet The success of .

But unfortunately ,telnet Grace stops at telnet Success and encounter the firewall was forced to disconnect the case , The output is the same ：

/wangying$ telnet xxx.xxx.xxx.xxx yyyy
Trying xxx.xxx.xxx.xxx yyyy
Connected to xxx.xxx.xxx.xxx.
Escape character is '^]'.
Connection closed by foreign host.

Want to know telnet The content of elegant stop can refer to my last blog ：
[telnet Batch test ( One )：telnet The pit between elegant parking and firewall ](https://blog.csdn.net/u012814856/article/details/115211805?spm=1001.2014.3001.5502)

In the last blog , I put forward telnet The question of elegance , It means using telnet Write in an elegant way telnet Batch test scripts are inaccurate . So here comes the question ：

How do we write telnet Batch test scripts ？

In this blog , Let's solve this problem .

Two 、 analysis

to want to telnet Batch test , The main problem is to be able to distinguish telnet Different outputs of different results , Especially finding telnet The difference between a successful situation and other situations .

Here I sum up telnet Four situations of ：

1. telnet success
This situation requires interactive input of escape characters ctrl + ], Then input q sign out telnet

$ /wangying$ telnet xxx.xxx.xxx.xxx yyyy
Trying xxx.xxx.xxx.xxx...
Connected to xxx.xxx.xxx.xxx.
Escape character is '^]'.
^]
telnet> q
Connection closed.

2. telnet Connection established successfully , But it was cut off by the other party's firewall

/wangying$ telnet xxx.xxx.xxx.xxx yyyy
Trying xxx.xxx.xxx.xxx yyyy
Connected to xxx.xxx.xxx.xxx.
Escape character is '^]'.
Connection closed by foreign host.

3. The opposite port is not started

/wangying$ telnet xxx.xxx.xxx.xxx yyyy
Trying xxx.xxx.xxx.xxx...
telnet: connect to xxx.xxx.xxx.xxx: Connection resused

4. The route cannot reach the corresponding server

/wanying$ telnet xxx.xxx.xxx.xxx yyyy
Trying xxx.xxx.xxx.xxx...

If we can manually write escape characters into the code ctrl + ] Words , You can use a unique string Connection closed. To distinguish between telnet Is it successful .

3、 ... and 、 solve

Fortunately , We can write escape characters manually ：

sleep 0.4; echo -e '\x1d' | telnet xxx.xxx.xxx.xxx yyyy

What this command means is ：telnet xxx.xxx.xxx.xxx yyyy after , Stop 0.4 Write in seconds \x1d character , This character is ctrl + ] Escape character ASCII Code value 16 Mechanism means .

Through this line of key code , We will be able to achieve telnet Batch test scripts ：）

Four 、 summary

To achieve a complete telnet A lot of other knowledge is needed for batch testing scripts , for instance ：

1. How to extract from the specified text grep come out ip and port Information , This one needs regular expressions
2. How to integrate telnet The test results are printed to the screen 、 Write to a file
3. How to solve telnet The problem of file writing when the test script is repeatedly executed
4. How to solve grep IFS Related issues

Above questions , They are all concrete telnet Problems in writing batch test scripts , This is not discussed in detail in this blog , I believe that those who have a heart will explore and solve it by themselves ~~~

To be Stronger：）