Usage of the Linux sed command

Original http://blog.chinaunix.net/uid-24426415-id-77244.html

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Beginner's entry

the SED tool is a non-interactive stream editor. By default, only the output is affected and the input is not changed . An SED is a unit of behavior when processing a document. Features are: Delete, find replace, add , insert, read from other files.

In fact, these functions seem to be implemented with vim and other editors. So, why do we have sed?

main application Scenarios

• Too large a text
• Regular text changes

Command format for SED

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Delete

#删除第一行sed ‘1d‘ file

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Note that this only affects the output stream. If you want to save it,

-i ‘1d‘ filename

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Or

#输出到新文件sed ‘1d‘>newfilename

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where the 1d command, we call 1 address, here refers to the first line.
Delete First line to last row

sed ‘1,$d‘ filename

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Delete a line that contains a pattern

‘/pattern/d‘ filename#例如sed ‘/^$/d‘ filename

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Find Replacements

#普通替换 将每行的第一个line替换成LINEsed ‘s/line/LINE/‘ filename

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Sed ' s/line/line/[number]
Represents the maximum number of lines to replace in this line, and if number is G, replace all

Character Conversions

现在还没有见过重要的用法

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Insert Text

#在第二行前插入一行sed ‘2 i insert_context‘ filename#在第二行之后插入一行sed ‘2 a insert_context‘ filename#在匹配的行之前插入一行sed ‘/pattern/i\new_word‘ filename

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Print

#只打印出第一行 ，不加n的话会默认输出每一行sed -n ‘1p‘ filename#只打印出被修改的一行sed -n ‘s/the/THE/p‘ filename

Usage of the Linux sed command