Linux sed and grep

Linux sed

1.替换标记
$ cat data4
This is a test of the test script.
This is the second test of the test script.

$ sed 's/test/trail/' data4
This is a trail of the test script.
This is the second trail of the test script.

       's/pattern/replacement/flags'.
  flags:  数字:替换位置（第几个出现位置，不填则默认首次出现文本）
          g:替换全部
          p:和-n sed选项一起使用，只打印替换的行.
          w file:将替换结果写入文件.

2.替换字符
$ sed 's!/bin/bash!/bin/bash/csh!' /etc/passwd.

3.使用地址
1）数字式行寻址
$ sed '2s/dog/cat/' data1         //指定sed命令将应用的那一行的行号
The quick brown fox jumps over the lazy dog.
The quick brown fox jumps over the lazy cat.
The quick brown fox jumps over the lazy cat.
The quick brown fox jumps over the lazy dog.

$ '2,4s/dog/cat/' data1           //仅修改指定地址第三行中文本
The quick brown fox jumps over the lazy dog.
The quick brown fox jumps over the lazy cat.
The quick brown fox jumps over the lazy cat.
The quick brown fox jumps over the lazy cat.

$ '2,$s/dog/cat/' data1           //指定位置到文本结束

2）文本模式筛选
$ sed '/rich/s/bash/csh/' /etc/passwd

3)组合命令
$ sed '2{
>s/fox/elephant/
>s/cat/dog/
>}' data1
The quick brown fox jumps over the lazy dog.
The quick brown elephant jumps over the lazy dog.
The quick brown fox jumps over the lazy dog.
The quick brown fox jumps over the lazy dog.

$ sed '3,${
>s/brown/green/
>s/lazy/active/
>}' data1
The quick brown fox jumps over the lazy dog.
The quick brown fox jumps over the lazy cat.
The quick green fox jumps over the active dog.
The quick green fox jumps over the active dog.

4.删除行
$ sed 'd' data1

$ sed '3d' data1
The quick brown fox jumps over the lazy dog.
The quick brown fox jumps over the lazy cat.
The quick brown fox jumps over the lazy dog.

$ sed '2,$d' data1
The quick brown fox jumps over the lazy dog.

$ sed '/lazy dog/d' data1
The quick brown fox jumps over the lazy cat.

5.插入和附加文本
$ echo "testing" |sed 'i\        //在指定行前加一行             a\指定行后加一行
>This is a test'
This is a test 
testing

$ sed '3i\
>This is a test'                //数据流第3行前加              3a\数据流第3行后加

$ sed '$a\                      //文本末尾加                    1i\文本首加

6.更改行
$ sed '3c\                      //更改第三行内容                  $ sed '/本行关键字/c\
>This is a test'                                                   >This is a test'

7.变换命令
$ echo "This 1 is a test of 1 try." |sed 'y/123/456/'
This 4 is a test of 4 try.

8.打印命令
1）打印行
$ echo "This is a test" |sed 'p'
This is a test.
This is a test

$ sed -n '/3/{
>p
>s/line/test/p
>}' data6
This is line number 3.
This is test number 3.

2)打印行号
$ sed '=' data1                                                     $ sed -n '/number 4/{
1.The quick brown fox jumps over the lazy cat.                      >=
2.The quick brown fox jumps over the lazy cat.                      >p
3.The quick brown fox jumps over the lazy cat.                      >}' data6
4.The quick brown fox jumps over the lazy dog.                      4.This is line number 4.

9.写文件
$ sed '1,2w test' data6                                             $ sed -n '/cat/w cat2' data4
$ cat test                                                          $ cat cat2
This is line number 1.                                              This quick brown fox jumps over the lazy cat.
This is line number 2.

10.从文件读数据
$ cat cat2
This quick brown fox jumps over the lazy cat.
$ sed '3r cat2' data4
The quick brown fox jumps over the lazy dog.
The quick brown fox jumps over the lazy cat.
The quick brown fox jumps over the lazy dog.
The quick brown fox jumps over the lazy cat.
The quick brown fox jumps over the lazy dog.

$ sed '/number 2/r cat2' data6
$ sed '$r cat2' data6                                              将cat2中内容插入data6末尾



Linux grep

$ grep linuxtechi /etc/passwd                                     在/etc/passed/中查找含linuxtechi的

$ grep -l linuxtechi /etc/passwd /etc/shadow                      列出包含linuxtechi的文件名
$ grep -n linuxtechi /etc/passwd /etc/shadow                      显示匹配的行号
$ grep -v linuxtechi /etc/passwd /etc/shadow                      显示不包含linuxtechi的行
$ grep ^root linuxtechi /etc/passwd /etc/shadow                   显示以root开头的行
$ grep bash$ linuxtechi /etc/passwd /etc/shadow                   显示以bash结束的尾
$ grep -r linuxtechi /etc/                                        在/etc目录中查找”linuxtechi”
$ grep ^$ /etc/shadow                                             查找空行
$ grep -i linuxtechi                                              查找含linuxtechi，不区分大小写
$ grep -e "linuxtechi" -e "root" /etc/passwd                      查找多个单词
$ grep -c "linuxtechi"                                            匹配到的数量
$ grep -B4 "games" /etc/passwd                                    匹配行前4行
$ grep -A4 "games" /etc/passwd                                    匹配行后4行
$ grep -C "games" /etc/passwd                                     匹配行前后各4行
$ grep -[A] "games"/etc/passwd                                    匹配单个字符
$ grep -[A-Z] "games" etc/passwd                                  匹配范围
$ grep 。"games" /etc/passwd                                      所有单个字符
$ grep '[a-z]\{5\}' aa                                            显示所有包含每个字符串至少有5个连续小写字符的字符串的行