One 、sed Command Introduction

sed yes liunx An external command provided in , It's a line （ flow ） Editor , Non interactive operation of adding, deleting, modifying, inserting and querying the contents of the file , Users can only enter editing commands on the command line , Specify a filename , Then look at the output on the screen , It is essentially different from text editor .

The difference is that ：
Text editor ： Editing objects are files
Line editor ： The edit object is a line in the file

Two 、 grammar

sed [-hnV][-e<script>][-f<script file >][ text file ]

 Parameter description ：

-e<script> or --expression=<script>  As specified in the options script To process the input text file .
-f<script file > or --file=<script file >  As specified in the options script File to process the input text file .
-i         Edit file contents 
-i.bak     Create while modifying .bak Backup file 
-r         Use extended regular expressions 
！         Take the opposite   （ Follow the pattern condition and shell Somewhat different ）
-h         or --help  Display help .
-n         or --quiet or --silent  Show only script The result of the treatment .
-V         or --version  Display version information .  Action description ：

a ： newly added , a  You can use a string after , And these strings will appear on a new line ( The next line at the moment )～ 
c ： replace , c  You can use a string after , These strings can replace  n1,n2  Between the lines ！
d ： Delete , Because it's deletion , therefore  d  There's usually nothing in the back ; 
i ： Insert , i  You can use a string after , And these strings will appear on a new line ( The current line ); 
p ： Print , Will also print out some selected data . Usually  p  And parameters  sed -n  Run together ～ 
s ： replace , Can be replaced directly by work ！ Usually the  s  The action can be combined with normal expression ！ for example  1,20s/old/new/g  That's it ！

3、 ... and 、 Example demonstration

1） Additional ：sed ‘a\ Additional content ’ file name ‘\’ It can be omitted

# Add a line after each line “hello world”
[root@localhost shell]# sed 'a\hello world' sed.sh
sdf
hello world
sgajglasjg
hello world
wewgjasldjg
hello world
sdnval;jgqwe
hello world
14213rwfsq92j
hello world

hello world
# stay 2 To 4 Add a line after the line “hello world”
[root@localhost shell]# sed '2,4a\hello world' sed.sh
sdf
sgajglasjg
hello world
wewgjasldjg
hello world
sdnval;jgqwe
hello world
14213rwfsq92j
# stay 4 Add a line after the line “hello world”
[root@localhost shell]# sed '4a\hello world' sed.sh
sdf
sgajglasjg
wewgjasldjg
sdnval;jgqwe
hello world
14213rwfsq92j
# matching “wew” Where the line is , And add a line after it “hello world”
[root@localhost shell]# sed '/wew/a\hello world' sed.sh
sdf
sgajglasjg
wewgjasldjg
hello world
sdnval;jgqwe
14213rwfsq92j

2） Insert ：sed ‘i\ Insert content ’ file name

# Insert a line before each line “hello world”
[root@localhost shell]# sed 'i\hello world' sed.sh
hello world
sdf
hello world
sgajglasjg
hello world
wewgjasldjg
hello world
sdnval;jgqwe
hello world
14213rwfsq92j
hello world
# In the 3 Insert a line before the line “hello world”
[root@localhost shell]# sed '3i\hello world' sed.sh
sdf
sgajglasjg
hello world
wewgjasldjg
sdnval;jgqwe
14213rwfsq92j
# stay 2 To 4 Insert a line before the line “hello world”
[root@localhost shell]# sed '2,4i\hello world' sed.sh
sdf
hello world
sgajglasjg
hello world
wewgjasldjg
hello world
sdnval;jgqwe
14213rwfsq92j
# matching “wew” Where the line is , And insert a line before it “hello world”
[root@localhost shell]# sed '/wew/i\hello world' sed.sh
sdf
sgajglasjg
hello world
wewgjasldjg
sdnval;jgqwe
14213rwfsq92j

3） Delete ：sed ‘d/ Deleted content ’ file name

# Delete all 
[root@localhost shell]# sed 'd' sed.sh
# Delete the third line 
[root@localhost shell]# sed '3d' sed.sh
sdf
sgajglasjg
sdnval;jgqwe
14213rwfsq92j
# Delete 3 To 4 That's ok 
[root@localhost shell]# sed '3,4d' sed.sh
sdf
sgajglasjg
14213rwfsq92j
# matching “wew” Where the line is 
[root@localhost shell]# sed '/wew/d' sed.sh
sdf
sgajglasjg
sdnval;jgqwe
14213rwfsq92j
# Delete nginx.conf In file # The first line may contain # Line or blank line 
#‘-r’ Indicates support for regular expressions 
#‘^$’ Indicates an empty line 
[root@localhost shell]# sed -r '/(^#|#|^$)/d' nginx.conf
worker_processes  1;
events {
    
    worker_connections  1024;
}
http {
    
    include       mime.types;
    default_type  application/octet-stream;
    sendfile        on;
    keepalive_timeout  65;
    server {
    
        listen       80;
        server_name  localhost;
        location / {
    
            root   html;
            index  index.html index.htm;
        }
        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
    
            root   html;
        }
    }
}

4） Replace ：sed ‘s/ Replaced characters / Content after replacement /’ file name

# Put the first character of each line ‘g’ Replace with ‘A’
[root@localhost shell]# sed 's/g/A/' sed.sh
sdf A
sAajglasjg
wewAjasldjg
sdnval;jAqweg
14213rwfsq92jA
# Put the first character of the third line ‘g’ Replace with ‘A’
[root@localhost shell]# sed '3s/g/A/' sed.sh
sdf g
sgajglasjg
wewAjasldjg
sdnval;jgqweg
14213rwfsq92jg
# take 2 To 4 The first character of the line ‘g’ Replace with ‘A’
[root@localhost shell]# sed '2,4s/g/A/' sed.sh
sdf g
sAajglasjg
wewAjasldjg
sdnval;jAqweg
14213rwfsq92jg
# matching ‘wew’ The first character of the line ‘g’ Replace with ‘A’
[root@localhost shell]# sed '/wew/s/g/A/' sed.sh
sdf g
sgajglasjg
wewAjasldjg
sdnval;jgqweg
14213rwfsq92jg

5） change ：sed ‘c\ What's changed ’ file name

# Change all rows to hell oword
[root@localhost shell]# sed 'c\hell oword' sed.sh
hell oword
hell oword
hell oword
hell oword
hell oword
hell oword
# Change the third line to hell oword
[root@localhost shell]# sed '3c\hell oword' sed.sh
sdf g
sgajglasjg
hell oword
sdnval;jgqweg
14213rwfsq92jg
# Change the third to fourth lines to hell oword
[root@localhost shell]# sed '3,4c\hell oword' sed.sh
sdf g
sgajglasjg
hell oword
14213rwfsq92jg
# matching ‘wew’ The line is changed to hell oword
[root@localhost shell]# sed '/wew/c\hell oword' sed.sh
sdf g
sgajglasjg
hell oword
sdnval;jgqweg
14213rwfsq92jg

5） transformation ：sed ‘y/ What is being converted / Content of conversion /’ file name

# take a convert to U; take b convert to B; take c convert to L
[root@localhost shell]# sed 'y/abc/UBL/' sed.sh
sdf g
sgUjglUsjg
wewgjUsldjg
sdnvUl;jgqweg
14213rwfsq92jg

6） Print ：sed ‘p/ Printed lines ’ file name

7） Edit the structure of the save process ：sed -i ’ ’

sed -i.bak Back up the source file

[root@localhost shell]# sed -i '/wew/c\hell oword' sed.sh
[root@localhost shell]# cat sed.sh
sdf g
sgajglasjg
hell oword
sdnval;jgqweg
14213rwfsq92jg
[root@localhost shell]# sed -i.bak '4,5c\hell oword' sed.sh
[root@localhost shell]# ls
ip.sh  nginx.conf  nginx.sh  sed.sh  sed.sh.bak  while  zzbds.sh
[root@localhost shell]# cat sed.sh
sdf g
sgajglasjg
hell oword
hell oword

[root@localhost shell]# cat sed.sh.bak
sdf g
sgajglasjg
hell oword
sdnval;jgqweg
14213rwfsq92jg

Four 、sed Command parsing

command	explain
Numbers	Represents the new text replacement mode
g	Represents replacing all instances of existing text with new text
p	Indicates that the original content is printed
w filename	Write the replacement result to the file

demonstration

# Numbers , The default is to replace the first... Of each line , Adding numbers means the first few characters 
[root@localhost shell]# sed 's/g/A/2' sed.sh

#g Replace all of each line 
[root@localhost shell]# sed 's/g/A/g' sed.sh

#p  Print 
[root@localhost shell]# sed '3s/g/A/p' sed.sh

#w  file name   Save the modified content  filename In file 
[root@localhost shell]# sed '3s/g/A/w filename' sed.sh

Suppress memory output , Print on request ：sed -n

[root@localhost shell]# sed -n '3s/g/A/p' sed.sh

Execute multiple instructions ：sed -e

[root@localhost shell]# sed -e '3s/g/A/p;3s/b/C/p' sed.sh

Specifies the file where the directive is stored ：sed -f
First, store the instructions to be executed in a file , Such as the “3s/g/A/p;3s/b/C/p” There is test.txt In file

[root@localhost shell]# sed -f test.txt sed.sh