[TOC]

sed notes

what is sed?

sed is a stream editor. A stream editor is used to perform basic text transformations on an input stream (a file or input from a pipeline).

语法

sed OPTIONS... [SCRIPT] [INPUTFILE...]

选项

选项	解释
-f script-file	添加script-file到命令
-i [suffix]	就地编辑。suffix指定备份文件后缀名
-n/–quiet/ – slient	slient
-e script	添加script到命令

基础

• 命令结构：

  [address[, address]] instruction [argument-list]

  地址(address)

  类似于awk的范围模式。$表示最后一行。

  指令

指令	解释
a (append)	append text after a line
c (change)	change lines with text
d (delete)	stop processing the current line, immediately start next cycle
i (insert)	insert text before a line
N (next without write)	add a newline to the pattern space, then append the next line of input to the pattern space
n (next)	print the pattern space, then replace the pattern space with the next line of input
p (print)	print the pattern space
q (quit)	exit
r filename (read)	read text of a file
s (substitute)	format: s/regexp/replacement/[flags]
w filename (write)	write the pattern space to filename

### 控制结构

符号	解释
! (NOT)	not
{}	将一组指令括起来，用$;$将多条指令隔开
:label	标记一个位置，作为跳转目标
b [label]	无条件转移
t [label]	匹配成功则转移

### 暂存空间

符号	解释
g	将暂存空间的内容复制到模式空间中，模式空间中原来的内容丢失
G	将一个换行符和暂存空间中的内容append到模式空间中
h	将模式空间中的内容复制到暂存空间中，暂存空间中原来的内容丢失
H	将一个换行符和模式空间中的内容append到暂存空间中
x	交换模式空间和暂存空间中的内容

### regular expression extensions

symbol	explanation
\w	any “word” character (字母、数组、下划线)
\W	any “non-word” character
\b	a word boundary
\B	every but on a word boundary
\s	whitespace characters (空格、tab、暂存空间和模式空间中的回车)
\S	non-whitespace characters
\<	beginning of a word
\>	end of a word
\`	start of pattern space, different from ^
\’	end of pattern space, different from $