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204 lines
6.7 KiB
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204 lines
6.7 KiB
Markdown
Translating-----------geekpi
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15 Practical Examples of ‘echo’ command in Linux
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================================================================================
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**echo** is one of the most commonly and widely used built-in command for Linux bash and C shells, that typically used in scripting language and batch files to display a line of text/string on standard output or a file.
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echo command examples
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The syntax for echo is:
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echo [option(s)] [string(s)]
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**1.** Input a line of text and display on standard output
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$ echo Tecmint is a community of Linux Nerds
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Outputs the following text:
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Tecmint is a community of Linux Nerds
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**2.** Declare a variable and echo its value. For example, Declare a variable of **x** and assign its value=**10**.
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$ x=10
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echo its value:
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$ echo The value of variable x = $x
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The value of variable x = 10
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**Note:** The ‘**-e**‘ option in Linux acts as interpretation of escaped characters that are backslashed.
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**3.** Using option ‘**\b**‘ – backspace with backslash interpretor ‘**-e**‘ which removes all the spaces in between.
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$ echo -e "Tecmint \bis \ba \bcommunity \bof \bLinux \bNerds"
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TecmintisacommunityofLinuxNerds
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**4.** Using option ‘**\n**‘ – New line with backspace interpretor ‘**-e**‘ treats new line from where it is used.
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$ echo -e "Tecmint \nis \na \ncommunity \nof \nLinux \nNerds"
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Tecmint
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is
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a
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community
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of
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Linux
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Nerds
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**5.** Using option ‘**\t**‘ – horizontal tab with backspace interpretor ‘**-e**‘ to have horizontal tab spaces.
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$ echo -e "Tecmint \tis \ta \tcommunity \tof \tLinux \tNerds"
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Tecmint is a community of Linux Nerds
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**6.** How about using option new Line ‘**\n**‘ and horizontal tab ‘**\t**‘ simultaneously.
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$ echo -e "\n\tTecmint \n\tis \n\ta \n\tcommunity \n\tof \n\tLinux \n\tNerds"
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Tecmint
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is
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a
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community
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of
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Linux
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Nerds
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**7.** Using option ‘**\v**‘ – vertical tab with backspace interpretor ‘**-e**‘ to have vertical tab spaces.
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$ echo -e "\vTecmint \vis \va \vcommunity \vof \vLinux \vNerds"
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Tecmint
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is
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a
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community
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of
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Linux
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Nerds
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**8.** How about using option new Line ‘**\n**‘ and vertical tab ‘**\v**‘ simultaneously.
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$ echo -e "\n\vTecmint \n\vis \n\va \n\vcommunity \n\vof \n\vLinux \n\vNerds"
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Tecmint
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is
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a
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community
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of
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Linux
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Nerds
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**Note:** We can double the vertical tab, horizontal tab and new line spacing using the option two times or as many times as required.
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**9.** Using option ‘**\r**‘ – carriage return with backspace interpretor ‘**-e**‘ to have specified carriage return in output.
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$ echo -e "Tecmint \ris a community of Linux Nerds"
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is a community of Linux Nerds
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**10.** Using option ‘**\c**‘ – suppress trailing new line with backspace interpretor ‘**-e**‘ to continue without emitting new line.
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$ echo -e "Tecmint is a community \cof Linux Nerds"
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Tecmint is a community avi@tecmint:~$
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**11.** Omit echoing trailing new line using option ‘**-n**‘.
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$ echo -n "Tecmint is a community of Linux Nerds"
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Tecmint is a community of Linux Nerdsavi@tecmint:~/Documents$
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**12.** Using option ‘**\a**‘ – alert return with backspace interpretor ‘**-e**‘ to have sound alert.
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$ echo -e "Tecmint is a community of \aLinux Nerds"
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Tecmint is a community of Linux Nerds
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**Note:** Make sure to check Volume key, before firing.
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**13.** Print all the files/folder using echo command (ls command alternative).
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$ echo *
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103.odt 103.pdf 104.odt 104.pdf 105.odt 105.pdf 106.odt 106.pdf 107.odt 107.pdf 108a.odt 108.odt 108.pdf 109.odt 109.pdf 110b.odt 110.odt 110.pdf 111.odt 111.pdf 112.odt 112.pdf 113.odt linux-headers-3.16.0-customkernel_1_amd64.deb linux-image-3.16.0-customkernel_1_amd64.deb network.jpeg
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**14.** Print files of a specific kind. For example, let’s assume you want to print all ‘**.jpeg**‘ files, use the following command.
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$ echo *.jpeg
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network.jpeg
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**15.** The echo can be used with redirect operator to output to a file and not standard output.
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$ echo "Test Page" > testpage
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## Check Content
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avi@tecmint:~$ cat testpage
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Test Page
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### echo Options ###
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<table border="0" cellspacing="0">
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<colgroup width="85"></colgroup>
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<colgroup width="271"></colgroup>
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<tbody>
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<tr>
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<td style="border: 1px solid #000000;" align="LEFT" height="16"><b> Options</b></td>
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<td style="border: 1px solid #000000;" align="LEFT"><b> Description</b></td>
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</tr>
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<tr>
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<td style="border: 1px solid #000000;" align="LEFT" height="16"><b> -n</b></td>
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<td style="border: 1px solid #000000;" align="LEFT"> do not print the trailing newline.</td>
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</tr>
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<tr>
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<td style="border: 1px solid #000000;" align="LEFT" height="16"><b> -e</b></td>
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<td style="border: 1px solid #000000;" align="LEFT"> enable interpretation of backslash escapes.</td>
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</tr>
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<tr>
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<td style="border: 1px solid #000000;" align="LEFT" height="16"><b> \b</b></td>
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<td style="border: 1px solid #000000;" align="LEFT"> backspace</td>
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</tr>
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<tr>
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<td style="border: 1px solid #000000;" align="LEFT" height="16"><b> \\</b></td>
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<td style="border: 1px solid #000000;" align="LEFT"> backslash</td>
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</tr>
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<tr>
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<td style="border: 1px solid #000000;" align="LEFT" height="16"><b> \n</b></td>
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<td style="border: 1px solid #000000;" align="LEFT"> new line</td>
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</tr>
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<tr>
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<td style="border: 1px solid #000000;" align="LEFT" height="16"><b> \r</b></td>
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<td style="border: 1px solid #000000;" align="LEFT"> carriage return</td>
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</tr>
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<tr>
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<td style="border: 1px solid #000000;" align="LEFT" height="16"><b> \t</b></td>
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<td style="border: 1px solid #000000;" align="LEFT"> horizontal tab</td>
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</tr>
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<tr>
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<td style="border: 1px solid #000000;" align="LEFT" height="16"><b> \v</b></td>
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<td style="border: 1px solid #000000;" align="LEFT"> vertical tab</td>
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</tr>
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</tbody>
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</table>
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That’s all for now and don’t forget to provide us with your valuable feedback in the comments below.
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--------------------------------------------------------------------------------
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via: http://www.tecmint.com/echo-command-in-linux/
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作者：[Avishek Kumar][a]
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译者：[译者ID](https://github.com/译者ID)
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校对：[校对者ID](https://github.com/校对者ID)
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本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](http://linux.cn/) 荣誉推出
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[a]:http://www.tecmint.com/author/avishek/ |