echo Command Explanation

echo Command: (refer to the man document for specific usage and explanation)

Feature Description: Display characters
Syntax: Echo [short-option] ... [String]

Echo long-option
Additional note: Echo will send the input string to standard output. The output strings are separated by white space characters, and a newline number is added at the end.
parameter:-n do not wrap in the last line
- E If the following characters appear in the string, they are handled in particular, not as a general
Text output:
\a issued a warning sound;
\b Delete the previous character;
\c finally not add the line break symbol;
\f the line but the cursor remains in its original position;
\ n Wraps and the cursor moves to the beginning of the line;
\ r The cursor moves to the beginning of the line, but does not wrap;
\ t Insert tab;
\v is the same as \f;
\ \ insert \ character;
\nnn Inserts the ASCII character represented by the NNN (octal);
--help Display Help
--version displaying version information

String can use quotation marks, both single and double quotation marks can be

Where single quotes represent strong references, variable references are not replaced:

[Email protected]~]# echo ' $SHELL '

$SHELL

Double quotes represent weak references, and variables are replaced:

[Email protected]~]# echo "$SHELL"

/bin/bash

echo Display in Shell color display, echo display with color, need to use parameter-E

The format is as follows:

echo-e "\033[word background color; text color m string \033[0m"

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of which the position represents the background, $ the position is the color of the representative word

Note:
1　　, the word background color and the text color are in English"" 
2　　, the text color is followed by am
3　　, there can be no space before and after the string, if any, the output also has a space 
here is the corresponding word and background color, you can try to find out the different color collocation

echo-e "\033[31mRed Word\033[0m "
echo-e "\033[34mYellow Word\033[0m "
echo-e "\033[41;33mRed Bottom Yellow word\033[0m "
echo-e "\033[41;37mWhite on red background\033[0m "

The meanings indicated by the figures are as follows :

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Job : Use the echo command for flashing, underlining, and color functions

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[Email protected] ~]# echo-e "\033[40;31;4;5m*******\n *****\n ***\n *\033[0m"

650) this.width=650; "src=" Http://s4.51cto.com/wyfs02/M00/84/97/wKioL1eVshaAxPuXAAAT96yvj1o377.png "title=" QQ picture 20160725143120.png "alt=" Wkiol1evshaaxpuxaaat96yvj1o377.png "/>

echo Command Explanation