Sed command

Catalog

One 、sed summary

1、sed Principle

2、sed The process of

3、sed Common options for

Two 、sed The use of

1、sed Query operation of

2、sed Delete operation

3、sed Replacement operation of

4、sed Add content operation

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One 、sed summary

1、sed Principle

sed Is a flow editor , The flow editor will edit the data flow based on a set of rules provided in advance before the editor processes the data .

sed The editor can process the data in the data stream according to the command , These commands are either entered from the command line , Or stored in a command text .

2、sed The process of

（1） Read process

sed From the input stream （ file 、 The Conduit 、 The standard input ） Read a line in and store it in a temporary buffer （ Also called pattern space ）

（2） Execute the process

By default , be-all sed Commands are executed smoothly in pattern space , Unless the address of the line is specified , otherwise sed command , Will be executed on all lines in turn .

（3） Show process

Send the modified content to the output stream . After sending the data , Mode space will be cleared , Before all the file contents are processed , The above process is repeated , Until the content is processed .

3、sed Common options for

（1） Command format

sed  -e   ' operation '    file 1  file 2

sed -n -e ' operation '  file 1  file 2

sed  -f  Script files     file 1  file 2

sed -e -i   ' operation '    file 1    file 2

（2） Common options

（1）-e  or   --expression

Indicates that the input text file is processed with the specified command , When there is only one operation command, you can omit , It is generally used when executing multiple operation commands .

（2）-f or --file

Indicates that the input text file is processed with the specified script file

（3）-h  or   --help

Display help

（4）-n or s --quiet

prohibit sed Editor output , But you can p Command to complete the output

（5）i

Directly modify the text file

（3） Common operations

（1）s

Replace specified characters

（2）d

Delete the specified row

（3）a

Add a line of specified content to the specified line

（4）i

Insert a line of specified content on the specified line

（5）c

Replace the selected line with the specified content

（6）y

Character conversion , The converted characters must be the same length

（7）p

   Print , If you also specify a row , Indicates to print the specified line ; If no line is specified , It means printing everything ; If there are non printing characters , with AscII Code output . It is usually associated with _n" Use options together

（8）=

Print line number

（9）l

  Print text in the data stream and unprintable ASCII character （ Like the terminator s、 tabs \t）

Two 、sed Use

1、sed Query operation of

（1） Method 1

Use sed Command view /etc/shdaow

[root@localhost ~]# sed ' ' /etc/shadow
root:$6$3Rfh74ZoYVL60OLJ$atijevnzniTepczYYLv.WAJ9bmIT0vuOlM.7prgCRUjAeiDoeKd89c96baB32ajZH6G1/rq6DuVXyf3ktp7jY/::0:99999:7:::
bin:*:17110:0:99999:7:::
daemon:*:17110:0:99999:7:::
adm:*:17110:0:99999:7:::
lp:*:17110:0:99999:7:::
sync:*:17110:0:99999:7:::
shutdown:*:17110:0:99999:7:::
halt:*:17110:0:99999:7:::
mail:*:17110:0:99999:7:::
operator:*:17110:0:99999:7:::

（2） Method 2

[root@localhost ~]# sed -n  'p ' /etc/shadow
root:$6$3Rfh74ZoYVL60OLJ$atijevnzniTepczYYLv.WAJ9bmIT0vuOlM.7prgCRUjAeiDoeKd89c96baB32ajZH6G1/rq6DuVXyf3ktp7jY/::0:99999:7:::
bin:*:17110:0:99999:7:::
daemon:*:17110:0:99999:7:::
adm:*:17110:0:99999:7:::
lp:*:17110:0:99999:7:::
sync:*:17110:0:99999:7:::
shutdown:*:17110:0:99999:7:::
halt:*:17110:0:99999:7:::
mail:*:17110:0:99999:7:::
operator:*:17110:0:99999:7:::

View the specified line

[root@localhost ~]# sed -n '3p' /etc/shadow
daemon:*:17110:0:99999:7:::

  Using regular expressions

matching root Beginning line

[root@localhost ~]# sed -n '/^root/p' /etc/shadow
root:$6$3Rfh74ZoYVL60OLJ$atijevnzniTepczYYLv.WAJ9bmIT0vuOlM.7prgCRUjAeiDoeKd89c96baB32ajZH6G1/rq6DuVXyf3ktp7jY/::0:99999:7:::

View consecutive rows

see /etc/shadow Of 3 To 6 The content of the line

[root@localhost ~]# sed -n '3,6p' /etc/shadow
daemon:*:17110:0:99999:7:::
adm:*:17110:0:99999:7:::
lp:*:17110:0:99999:7:::
sync:*:17110:0:99999:7:::

 

Look at the last line of the file

[root@localhost ~]# sed -n '$p' /etc/shadow
zs:$6$LA7n3jCI3IvhMBHS$.9YqBUKpKwb9DHSIPX9KDVV4YJ5g04GxFQI8jdGx8XJoMqEgkdLrlAd03ahyCcjejZ7iKuO.Iv5OSlGxoSCTD.::0:99999:7:::

 

2、sed Delete operation

  Deleting a specified row is not really deleting , Just show the deleted results , Not really deleted , If you want to run in text, you need to cooperate -i command

Delete empty lines in text

[root@localhost ~]# sed '/^$/d' test.txt
12
24
23
334
234

  Delete the line specified in the file

[root@localhost ~]# sed '2d' t2.txt
123
789
321
451

3、 Replace

Command format

sed    Designated line       's/ String to replace / Replaced string / Replace mark

（1）g

Indicates that you want to replace all matching rows

（2）w

Save the replaced results to the document

Put... In the file 321 Replace with 345

[root@localhost ~]# sed 's/321/345/'    t2.txt
123
456
789
345
451

4、sed Add content operation

Add... Below the second line 234

[root@localhost ~]# sed '2a 234' t2.txt
123
456
234
789
321
451