sed是Linux中的一种文本流编辑器，可以将上一步操作的结果通过重定向的方式引入到sed中进行二次处理；也可以在不打开文件的情况下，对指定文件中匹配到指定条件的内容进行批量修改
1、作用
文本流行编辑器,不对源文件进行编辑，而是从指定文件中一次读取一行，经过处理后输出到屏幕，然后继续读取其他指定行进行处理
2、语法
sed [选项] [[n1[,n2]] 操作]
其中n1,n2表示选择操作的行数范围，例如需要对10到20行进行操作处理，则使用10,20[function]
3、常用选项
- -n：只将被处理过的行显示到屏幕上
- -e：直接在命令行模式下进行sed的操作编辑
- -f ：从指定文件中读取编辑脚本
- -r： 支持使用扩展正则表达式
- -i： 直接修改源文件,操作需谨慎
4、常用操作
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a：在当前行的 后面 插入文本，支持使用\n实现多行插入
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i ：在当前行的 前面 插入文本，支持使用\n实现多行插入
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c：可以将n1到n2之间行的内容替换为c后面跟的字符
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d：删除行，后面不需要跟内容
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p：显示指定行，通常配合-n使用
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s：替换指定数据
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替换使用方法
s/需要替换的字符/替换后的字符/[g/p/w]- 替换标记
g：行内全局替换
p：显示替换成功的行
w 文件：将替换成功的结果保存至指定文件中
- 替换标记
5、使用示例
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示例使用数据
[root@localhost ~]# nl test.txt 1 "Open Source" is a good mechanism to develop programs. 2 apple is my favorite food. 3 Football game is not use feet only. 4 this dress doesn't fit me. 5 However, this dress is about $ 3183 dollars. 6 GNU is free air not free beer. 7 Her hair is very beauty. 8 I can't finish the test. 9 Oh! The soup taste good. -
使用示例
# 显示指定行 [root@localhost ~]# nl test.txt | sed -n 2,5p 2 apple is my favorite food. 3 Football game is not use feet only. 4 this dress doesn't fit me. 5 However, this dress is about $ 3183 dollars. # 在指定行后面添加内容 [root@localhost ~]# nl test.txt | sed '2a---line_1---' 1 "Open Source" is a good mechanism to develop programs. 2 apple is my favorite food. ---line_1--- 3 Football game is not use feet only. 4 this dress doesn't fit me. .... # 在指定行前面添加内容 [root@localhost ~]# nl test.txt | sed '2i---line_1---' 1 "Open Source" is a good mechanism to develop programs. ---line_1--- 2 apple is my favorite food. 3 Football game is not use feet only. 4 this dress doesn't fit me. .... # 在指定内容处添加数据 [root@localhost ~]# sed '/apple is my favorite food./a\--- add line ---' test.txt 1 "Open Source" is a good mechanism to develop programs. 2 apple is my favorite food. --- add line --- 3 Football game is not use feet only. 4 this dress doesn't fit me. 5 However, this dress is about $ 3183 dollars. 6 GNU is free air not free beer. 7 Her hair is very beauty. 8 I can't finish the test. 9 Oh! The soup taste good. # 删除指定行 [root@localhost ~]# nl test.txt | sed '2,5d' 1 "Open Source" is a good mechanism to develop programs. 6 GNU is free air not free beer. 7 Her hair is very beauty. 8 I can't finish the test. 9 Oh! The soup taste good. # 从指定行开始，删除后面所有行 [root@localhost ~]# nl test.txt | sed '5,$d' 1 "Open Source" is a good mechanism to develop programs. 2 apple is my favorite food. 3 Football game is not use feet only. 4 this dress doesn't fit me. # 替换指定内容 ## 将示例中单个is替换成IS，并且只打印被替换的行 [root@localhost ~]# nl test.txt | sed -n 's/ is / IS /gp' 1 "Open Source" IS a good mechanism to develop programs. 2 apple IS my favorite food. 3 Football game IS not use feet only. 5 However, this dress IS about $ 3183 dollars. 6 GNU IS free air not free beer. 7 Her hair IS very beauty. ## 替换整行数据 [root@localhost ~]# nl test.txt | sed '2,5c 2-5 line' 1 "Open Source" is a good mechanism to develop programs. 2-5 line 6 GNU is free air not free beer. 7 Her hair is very beauty. 8 I can't finish the test. 9 Oh! The soup taste good. # 在最后一行的前面添加内容 [root@localhost tmp]# nl test.txt | sed '$i --- add line ---' 1 "Open Source" is a good mechanism to develop programs. 2 apple is my favorite food. 3 Football game is not use feet only. 4 this dress doesn't fit me. 5 However, this dress is about $ 3183 dollars. 6 GNU is free air not free beer. 7 Her hair is very beauty. 8 I can't finish the test. --- add line --- 9 Oh! The soup taste good. # 在最后一行的后面添加内容 [root@localhost tmp]# nl test.txt | sed '$a --- add line ---' 1 "Open Source" is a good mechanism to develop programs. 2 apple is my favorite food. 3 Football game is not use feet only. 4 this dress doesn't fit me. 5 However, this dress is about $ 3183 dollars. 6 GNU is free air not free beer. 7 Her hair is very beauty. 8 I can't finish the test. 9 Oh! The soup taste good. --- add line --- # 删除空白行 ## 由于可能存在特殊不可见字符，因此删除空白行可以使用以下方法 [root@localhost tmp]# sed '/^[[:space:]]*$/d' test.txt