Shulou(Shulou.com)06/03 Report--

In this issue, the editor will bring you about the meaning of echo. The article is rich in content and analyzes and narrates it from a professional point of view. I hope you can get something after reading this article.

ECHO is a computer command.

It can be based on the TCP protocol, and the server detects messages on TCP port 7. If the UDP protocol is used, the basic process is the same as TCP, and the detected port is also 7. Routing is also the most commonly used packet in the network. You can know which paths the current connecting node has by sending echo packets, and the path length can be obtained by round-trip time.

Echo contains three versions:

1.Echo1 achieves the effect of asynchronous communication through hidden Iframe, and its performance is relatively low.

2.Echo2 is the next generation version of the Echo Web framework. A framework that can be used to develop rich client applications based on Web. This version 2.0 still follows the core idea of Echo, but Echo2 provides a vivid user interface through its new AJAX presentation layer engine and improves overall performance and practicality.

3. The performance and ease of use of Echo3 have been greatly improved, and the official version has not yet been released.

Extended data:

ECHO system command

Function description: display text.

Syntax: echo [- ne] [string] or echo [--help] [--version]

Additional note: echo sends the input string to standard output. The output strings are separated by blank characters and are followed by a newline number.

Parameter:-n do not automatically wrap at the end

-e if the following characters appear in the string, they will be specially treated instead of being output as normal text:

\ a sound of warning

\ b Delete the previous character

\ c finally, no newline symbol is added.

\ f Wrap line, but the cursor remains in its original position

\ nWrap and the cursor moves to the beginning of the line

\ r move the cursor to the beginning of the line, but do not wrap

\ t insert tab

\ v is the same as\ f

\ insert\ character

\ nnn inserts ASCII characters represented by nnn (octal)

-- help displays help

-- version displays version information

The echo instructions supported by each shell may be quite different.

-n does not output the last\ n

-e interpreting escape characters

-E does not interpret escape characters

Example: echo "i am a boy" / / print i am a boy after execution

I am a boy

The above is what the meaning of echo shared by the editor is. If you happen to have similar doubts, you might as well refer to the above analysis to understand. If you want to know more about it, you are welcome to follow the industry information channel.

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