diff --git a/sources/tech/20190610 Expand And Unexpand Commands Tutorial With Examples.md b/sources/tech/20190610 Expand And Unexpand Commands Tutorial With Examples.md new file mode 100644 index 0000000000..01def369ed --- /dev/null +++ b/sources/tech/20190610 Expand And Unexpand Commands Tutorial With Examples.md @@ -0,0 +1,157 @@ +[#]: collector: (lujun9972) +[#]: translator: ( ) +[#]: reviewer: ( ) +[#]: publisher: ( ) +[#]: url: ( ) +[#]: subject: (Expand And Unexpand Commands Tutorial With Examples) +[#]: via: (https://www.ostechnix.com/expand-and-unexpand-commands-tutorial-with-examples/) +[#]: author: (sk https://www.ostechnix.com/author/sk/) + +Expand And Unexpand Commands Tutorial With Examples +====== + +![Expand And Unexpand Commands Explained][1] + +This guide explains two Linux commands namely **Expand** and **Unexpand** with practical examples. For those wondering, the Expand and Unexpand commands are used to replace TAB characters in files with SPACE characters and vice versa. There is also a command called “Expand” in MS-DOS, which is used to expand a compressed file. But the Linux Expand command simply converts the tabs to spaces. These two commands are part of **GNU coreutils** and written by **David MacKenzie**. + +For the demonstration purpose, I will be using a text file named “ostechnix.txt” throughout this guide. All commands given below are tested in Arch Linux. + +### Expand command examples + +Like I already mentioned, the Expand command replaces TAB characters in a file with SPACE characters. + +Now, let us convert tabs to spaces in the ostechnix.txt file and write the result to standard output using command: + +``` +$ expand ostechnix.txt +``` + +If you don’t want to display the result in standard output, just upload it to another file like below. + +``` +$ expand ostechnix.txt>output.txt +``` + +We can also convert tabs to spaces, reading from standard input. To do so, just run “expand” command without mentioning the source file name: + +``` +$ expand +``` + +Just type the text and hit ENTER to convert tabs to spaces. Press **CTRL+C** to quit. + +If you do not want to convert tabs after non blanks, use **-i** flag like below. + +``` +$ expand -i ostechnix.txt +``` + +We can also have tabs a certain number of characters apart, not 8 (the default value): + +``` +$ expand -t=5 ostechnix.txt +``` + +You can even mention multiple tab positions with comma separated like below. + +``` +$ expand -t 5,10,15 ostechnix.txt +``` + +Or, + +``` +$ expand -t "5 10 15" ostechnix.txt +``` + +For more details, refer man pages. + +``` +$ man expand +``` + +### Unexpand Command Examples + +As you may have already guessed, the **Unexpand** command will do the opposite of the Expand command. I.e It will convert SPACE charatcers to TAB characters. Let me show you a few examples to learn how to use Unexpand command. + +To convert blanks (spaces, of course) in a file to tabs and write the output to stdout, do: + +``` +$ unexpand ostechnix.txt +``` + +If you want to write the output in a file instead of just displaying it to stdout, use this command: + +``` +$ unexpand ostechnix.txt>output.txt +``` + +Convert blanks to tabs, reading from standard output: + +``` +$ unexpand +``` + +By default, Unexpand command will only convert the initial blanks. If you want to convert all blanks, instead of just initial blanks, use **-a** flag: + +``` +$ unexpand -a ostechnix.txt +``` + +To convert only leading sequences of blanks (Please note that it overrides **-a** ): + +``` +$ unexpand --first-only ostechnix.txt +``` + +Have tabs a certain number of characters apart, not **8** (enables **-a** ): + +``` +$ unexpand -t 5 ostechnix.txt +``` + +Similarly, we can mention multiple tab positions with comma separated like below. + +``` +$ unexpand -t 5,10,15 ostechnix.txt +``` + +Or, + +``` +$ unexpand -t "5 10 15" ostechnix.txt +``` + +For more details, refer man pages. + +``` +$ man unexpand +``` + +* * * + +**Suggested read:** + + * [**The Fold Command Tutorial With Examples For Beginners**][2] + + + +* * * + +When you working on large number of files, the Expand and Unexpand commands could be very helpful to replace unwanted TAB characters with SPACE characters and vice versa. + +-------------------------------------------------------------------------------- + +via: https://www.ostechnix.com/expand-and-unexpand-commands-tutorial-with-examples/ + +作者:[sk][a] +选题:[lujun9972][b] +译者:[译者ID](https://github.com/译者ID) +校对:[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译,[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: https://www.ostechnix.com/author/sk/ +[b]: https://github.com/lujun9972 +[1]: https://www.ostechnix.com/wp-content/uploads/2019/05/Expand-And-Unexpand-Commands-720x340.png +[2]: https://www.ostechnix.com/fold-command-tutorial-examples-beginners/