Linux命令日日说（十九）-- expand

expand

语法

expand [options] files

将文件中的tab字符转换成等宽的若干个space字符。虽然tab有助于排版，但不同编辑器的显示还是存在一定差别。多数IDE中tab的表现标准源头就在这里了。

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参数

• -t | --tab=NUM 指定tab字符的等效空格宽度（默认值为8）。

• -i | -- initial 只转换出现在行首的tab字符。

• --help 显示帮助文档

• --version 显示当前文本。

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Example

• expand test.txt

  标准替换为8个space。

  |zzw:~ zzw$ cat test.txt
  |       front with 2 tabs.
  |    front with 4 spaces.
  |  font with 2 spaces.
  |no tab and space.
  |   font with 1 tab.
  |  |                font with 2 space and 4 tabs.
  |zzw:~ zzw$ expand test.txt
  |                front with 2 tabs.
  |    front with 4 spaces.
  |  font with 2 spaces.
  |no tab and space.
  |        font with 1 tab.
  |  |                             font with 2 space and 4 tabs.
  

• expand -t 1 test.txt

  将tab替换为1个space的效果。

  |zzw:~ zzw$ cat test.txt
  |       front with 2 tabs.
  |    front with 4 spaces.
  |  font with 2 spaces.
  |no tab and space.
  |   font with 1 tab.
  |  |                font with 2 space and 4 tabs.
  |zzw:~ zzw$ expand -t 1 test.txt
  |  front with 2 tabs.
  |    front with 4 spaces.
  |  font with 2 spaces.
  |no tab and space.
  | font with 1 tab.
  |  |    font with 2 space and 4 tabs.
  

• expand --version

  root@895e4cf6e8a1:/# expand --version
  expand (GNU coreutils) 8.28
  Copyright (C) 2017 Free Software Foundation, Inc.
  License GPLv3+: GNU GPL version 3 or later .
  This is free software: you are free to change and redistribute it.
  There is NO WARRANTY, to the extent permitted by law.
  
  Written by David MacKenzie.