1:将文件中的某一行打印出来
[root@qht2 test]# cat a.txt
123
456
789
[root@qht2 test]# sed -n '1p' a.txt
123
[root@qht2 test]# sed '/hello/p' a.txt ###含有hello的行显示，其他的也要显示
hello I am zhang
hello I am zhang
Hello I am xiaojie
nice to see you xiaojie
nice to see you zhang too
12345
678
1
end
[root@qht2 test]# sed -n '/hello/p' a.txt ###仅显示包含hello字符串的行，即仅显示符合条件的行
hello I am zhang
[root@qht2 test]# cat a.txt
hello I am zhang
Hello I am xiaojie
nice to see you xiaojie
nice to see you zhang too
12345
678
1
end
[root@qht2 test]# sed '/[0-9]/p' a.txt
hello I am zhang
Hello I am xiaojie
nice to see you xiaojie
nice to see you zhang too
12345 ##含有数字的行显示2次
12345 ##含有数字的行显示2次
678
678
1
1
end
[root@qht2 test]# sed -n '/[0-9]/p' a.txt ##仅显示含有数字的行
12345
678
1
2：sed显示其中的几行
[root@qht2 test]# sed -n '1,3p' a.txt
123
456
789
[root@qht2 test]# sed -n '2,3p' a.txt
456
789
3：删除其中的几行，但文件本身并没有修改 ##d学习
[root@qht2 test]# cat a.txt
ab
bc
cd
de
ef
fg
hi
[root@qht2 test]# ls
a.txt
[root@qht2 test]# sed '2,3d' a.txt ###将文件的第2和3行删除，但不影响整个文件的内容
ab
de
ef
fg
hi
[root@qht2 test]# cat b.txt
Line one
The second line
The third
This is line four
Five
This is the sixth sentence
This is line seven.
Eighth and last
[root@qht2 test]# sed '$d' b.txt ##删除文件的最后一行
Line one
The second line
The third
This is line four
Five
This is the sixth sentence
This is line seven.
[root@qht2 test]# cat a.txt
hello I am zhang
Hello I am xiaojie
nice to see you xiaojie
nice to see you zhang too
12345
678
1
end
[root@qht2 test]# sed '/hello/d' a.txt ###删除含有hello字符的行
Hello I am xiaojie
nice to see you xiaojie
nice to see you zhang too
12345
678
1
end
[root@qht2 test]# sed '/hello/!d' a.txt ###删除不包含hello字符的行，!d表示不删除
hello I am zhang
[root@qht2 test]#
[root@qht2 test]# sed '/[0-9]/d' a.txt ##删除含有数字的行
hello I am zhang
Hello I am xiaojie
nice to see you xiaojie
nice to see you zhang too
end
[root@qht2 test]# sed '/[0-9]\{1\}/d' a.txt ##删除含有1个数字的行
hello I am zhang
Hello I am xiaojie
nice to see you xiaojie
nice to see you zhang too
end
[root@qht2 test]# sed '/[0-9]\{3\}/d' a.txt ##删除含有3个数字的行
hello I am zhang
Hello I am xiaojie
nice to see you xiaojie
nice to see you zhang too
1
end
[root@qht2 test]# sed 's/^...//g' a.txt ##删除开头的三个字符
lo I am zhang
lo I am xiaojie
e to see you xiaojie
e to see you zhang too
45
1
[root@qht2 test]# sed 's/...$//g' a.txt ##删除结尾的三个字符
hello I am zh
Hello I am xiao
nice to see you xiao
nice to see you zhang
12
1
[root@qht2 test]# sed '/^$/d' a.txt ##删除空行
hello I am zhang
Hello I am xiaojie
nice to see you xiaojie
nice to see you zhang too
12345
678
1
end
[root@qht2 test]# cat a.txt
hello I am zhang
Hello I am xiaojie
nice to see you xiaojie
nice to see you zhang too
12345
678
1
end
[root@qht2 test]# sed -i '/^$/d' a.txt ##-i表示执行后直接修改文件内容
[root@qht2 test]# cat a.txt
hello I am zhang
Hello I am xiaojie
nice to see you xiaojie
nice to see you zhang too
12345
678
1
end
3：在某一行后添加内容
[root@qht2 test]# sed '2a hello xiaojie' a.txt ##在第2行后添加hello xiaojie字符串
ab
bc
hello xiaojie
cd
de
ef
fg
hi
4：在某一行后添加几行
[root@qht2 test]# sed '2a hello\ ##在第2行后添加两行，行与行之间用\间隔
> xiaojie' a.txt
ab
bc
hello
xiaojie
cd
de
ef
fg
hi
5：字符串替换
[root@qht2 test]# sed '2,5c 555' a.txt 将2----5行替换成某个字符串或字符
ab
555
fg
hi
[root@qht2 test]# cat a.txt
hello I am zhang
Hello I am xiaojie
I see
AAA1111
nice to see you xiaojie
nice to see you zhang
12345
DDD
192.168.1.3
[root@qht2 test]# sed '1c\#!/bin/sh' a.txt ##加上\可以替换
#!/bin/sh
Hello I am xiaojie
I see
AAA1111
nice to see you xiaojie
nice to see you zhang
12345
DDD
192.168.1.3
[root@qht2 test]# sed '1c #!/bin/sh' a.txt ####不加上\也可以替换
#!/bin/sh
Hello I am xiaojie
I see
AAA1111
nice to see you xiaojie
nice to see you zhang
12345
DDD
192.168.1.3
[root@qht2 test]#
文件本身并没有修改
6：sed替换字符串
[root@qht2 test]# cat a.txt
hello I am zhang
Hello I am liu
nice to see you liu
nice to see you zhang too
[root@qht2 test]# sed 's/liu/xiaojie/g' a.txt
hello I am zhang
Hello I am xiaojie
nice to see you xiaojie
nice to see you zhang too
[root@qht2 test]# sed -i 's/liu/xiaojie/g' a.txt
[root@qht2 test]# cat a.txt
hello I am zhang
Hello I am xiaojie
nice to see you xiaojie
nice to see you zhang too
[root@qht2 test]# sed '3,4s/zhang//g' a.txt ###将3--4行中的zhang删掉(也可以理解为替换掉)
hello I am zhang
Hello I am xiaojie
nice to see you xiaojie
nice to see you t
12345
678
1
end
[root@qht2 test]# sed '/AAA/s/11/888/g' a.txt ###将含有AAA行的11替换为888
hello I am zhang
Hello I am xiaojie
AAA888888
nice to see you xiaojie
nice to see you zhang too
12345
DDD
678
1
end
7：sed使用-i参数之间修改文件内容
[root@qht2 test]# cat a.txt
hello I am zhang
Hello I am xiaojie
nice to see you xiaojie
nice to see you zhang too
[root@qht2 test]# ls
a.txt
[root@qht2 test]# sed -i '2,3d' a.txt
[root@qht2 test]# ls
a.txt
[root@qht2 test]# cat a.txt
hello I am zhang
nice to see you zhang too
[root@qht2 test]#
8：
最后一行添加一行内容
[root@qht2 test]# cat a.txt
hello I am zhang
Hello I am xiaojie
nice to see you xiaojie
nice to see you zhang too
[root@qht2 test]# sed -i '$a end' a.txt
[root@qht2 test]# cat a.txt
hello I am zhang
Hello I am xiaojie
nice to see you xiaojie
nice to see you zhang too
end
9:显示前2行
[root@qht2 test]# sed '2q' b.txt
Line one
The second line
[root@qht2 test]# head -n 2 b.txt ##head也可以实现
Line one
The second line
[root@qht2 test]# cat b.txt
Line one
The second line
The third
This is line four
Five
This is the sixth sentence
This is line seven.
Eighth and last
[root@qht2 test]#
10：-f表示sed应该从命令行上指定的文件中读取命令
[root@qht2 test]# cat print1_3
1,3 p
[root@qht2 test]# sed -n -f print1_3 b.txt
Line one
The second line
The third
[root@qht2 test]# cat b.txt
Line one
The second line
The third
This is line four
Five
This is the sixth sentence
This is line seven.
Eighth and last
[root@qht2 test]# cat append_demo
2 a\
alter.
[root@qht2 test]# sed -f append_demo b.txt
Line one
The second line
alter.
The third
This is line four
Five
This is the sixth sentence
This is line seven.
Eighth and last
[root@qht2 test]# cat insert_demo
/This/ i\
BEFORE
[root@qht2 test]# sed -f insert_demo b.txt
Line one
The second line
The third
BEFORE
This is line four
Five
BEFORE
This is the sixth sentence
BEFORE
This is line seven.
Eighth and last
[root@qht2 test]# cat subs_demo ##将文件中的line替换成sentence，并显示出来
s/line/sentence/p
[root@qht2 test]# cat b.txt
Line one
The second line
The third
This is line four
Five
This is the sixth sentence
This is line seven.
Eighth and last
[root@qht2 test]# sed -n -f subs_demo b.txt
The second sentence
This is sentence four
This is sentence seven.
[root@qht2 test]#
[root@qht2 test]# cat write_demo ##将替换后的行写入到temp文件里
s/line/sentence/w temp
[root@qht2 test]# sed -f write_demo b.txt ##将b.txt中的line替换成sentence
Line one
The second sentence
The third
This is sentence four
Five
This is the sixth sentence
This is sentence seven.
Eighth and last
[root@qht2 test]# ll
总计 32
-rw-r--r-- 1 root root 12 12-21 20:54 append_demo
-rw-r--r-- 1 root root 122 12-21 20:25 b.txt
-rw-r--r-- 1 root root 31 12-21 20:57 change_demo
-rw-r--r-- 1 root root 17 12-21 20:53 insert_demo
-rw-r--r-- 1 root root 6 12-21 20:46 print1_3
-rw-r--r-- 1 root root 18 12-21 21:12 subs_demo
-rw-r--r-- 1 root root 66 12-21 21:14 temp
-rw-r--r-- 1 root root 23 12-21 21:14 write_demo
[root@qht2 test]# cat temp
The second sentence
This is sentence four
This is sentence seven.
[root@qht2 test]# cat write_demo2
2,4 w temp2
[root@qht2 test]# sed -f write_demo2 b.txt
Line one
The second line
The third
This is line four
Five
This is the sixth sentence
This is line seven.
Eighth and last
[root@qht2 test]# ll temp2
-rw-r--r-- 1 root root 44 12-21 21:20 temp2
[root@qht2 test]# cat temp2
The second line
The third
This is line four
[root@qht2 test]# sed -f write_demo3 b.txt
Line one
The second line
The third
This is line four
Five
This is the sixth sentence
This is line seven.
Eighth and last
[root@qht2 test]# cat b.txt
Line one
The second line
The third
This is line four
Five
This is the sixth sentence
This is line seven.
Eighth and last
[root@qht2 test]# ll temp3
-rw-r--r-- 1 root root 78 12-21 21:27 temp3
[root@qht2 test]# cat temp3
Line one
Five
This is the sixth sentence
This is line seven.
Eighth and last
11:将某行开头的nice替换成mynice
[root@qht2 test]# cat a.txt
hello I am zhang
Hello I am xiaojie
I see
AAA1111
nice to see you xiaojie
nice to see you zhang too
12345
DDD
192.168.1.3
[root@qht2 test]# sed -n 's/^nice/mynice/p' a.txt ##-n仅仅显示符合条件的记录
mynice to see you xiaojie
mynice to see you zhang too
[root@qht2 test]#
[root@qht2 test]# cat a.txt
hello I am zhang
Hello I am xiaojie
I see
AAA1111
nice to see you xiaojie
nice to see you zhang too
12345
DDD
192.168.1.3
[root@qht2 test]# sed -i 's/see/&see/g' a.txt ##&表示替换换字符串中被找到的部份。
[root@qht2 test]# cat a.txt
hello I am zhang
Hello I am xiaojie
I seesee
AAA1111
nice to seesee you xiaojie
nice to seesee you zhang too
12345
DDD
192.168.1.3
[root@qht2 test]# cat a.txt
hello I am zhang
Hello I am xiaojie
I seesee
AAA1111
nice to seesee you xiaojie
nice to seesee you zhang too
12345
DDD
192.168.1.3
[root@qht2 test]# sed -i 's#to#toto#g' a.txt ###不论什么字符，紧跟着s命令的都被认为是新的分隔符，所以“#”在这里是分隔符，代替了默认的“/”分隔符
[root@qht2 test]# cat a.txt
hello I am zhang
Hello I am xiaojie
I seesee
AAA1111
nice toto seesee you xiaojie
nice toto seesee you zhang totoo
12345
DDD
192.168.1.3
[root@qht2 test]# cat a.txt
hello I am zhang
Hello I am xiaojie
I see
AAA1111
nice to see you xiaojie
nice to see you zhang
12345
DDD
192.168.1.3
[root@qht2 test]# sed 's/$/sedtsest/g' a.txt ###每行的末尾用字符串sedtest替换。
hello I am zhangsedtsest
Hello I am xiaojiesedtsest
I seesedtsest
AAA1111sedtsest
nice to see you xiaojiesedtsest
nice to see you zhang sedtsest
12345sedtsest
DDDsedtsest
192.168.1.3sedtsest
[root@qht2 test]# cat a.txt
hello I am zhang
Hello I am xiaojie
I see
AAA1111
nice to see you xiaojie
nice to see you zhang
12345
DDD
192.168.1.3
[root@qht2 test]# sed -n -e '1,4d' -e 's/nice/mynice/p' a.txt ###-e指定多个命令
mynice to see you xiaojie
mynice to see you zhang
[root@qht2 test]# sed -e '1,4d' -e 's/nice/mynice/p' a.txt
mynice to see you xiaojie
mynice to see you xiaojie
mynice to see you zhang
mynice to see you zhang
12345
DDD
192.168.1.3
12: -e 或-f 使用
13：
1~2 matches 1,3,5,7, etc.
2~2 matches 2,4,6,8, etc.
1~3 matches 1,4,7,10, etc.
2~3 matches 2,5,8,11, etc.
14：w 学习
