Use of the SED command in the shell

The SED stream editor is also a command in Linux that is often used in the shell to modify the contents of a file in a non-interactive way. The SED handles the text in rows, that is, one row at a time.
The basic format of the SED command is:
sed option ' edit directive ' file path
You can also use the pipe (|) Transfer parameters to SED processing Pre-command | sed option ' edit Command '

The common parameters of sed are:
-N Masks the default output, and if the-n option is not added, all output text satisfies the criteria of the row and then repeats the output
-R If you use extended regular, you need to add the-r option, the default does not support extended regular, only the standard regular
-I directly modifies the source file, without the-I will only be on the screen temporary output will not modify the source file, the General Test command is correct to use the-I option in the script
Editing instructions for SED:

P output

Command	Complete Example	Description
P	Sed-n ' P ' 1.txt	Output all lines of 1.txt
2p	Sed-n ' 2p ' 1.txt	Second line of output 1.txt
2,5p	Sed-n ' 2,5p ' 1.txt	The second line of output 1.txt to line fifth
2,+5p	Sed-n ' 2,+5p ' 1.txt	Output 1.txt second row and 5 rows after the second row
1~2p	Sed-n ' 1~2p ' 1.txt	Outputs the first line, one row per two lines, which is the output odd line
2~2p	Sed-n ' 1~2p ' 1.txt	Outputs the second line, one row per two lines, that is, the output even number of rows
/Regular/P	Sed-n '/^[0-9]/p ' 1.txt	Output 1.txt lines starting with a number
$=	Sed-n ' $= ' 1.txt	Number of rows for output 1.txt

d Delete

Command	Complete Example	Description
2d	Sed ' 2d ' 1.txt	Delete the second line of 1.txt
2,5d	Sed ' 2,5d ' 1.txt	Delete the second line of 1.txt to line fifth
2,+5d	Sed ' 2,+5d ' 1.txt	Delete the second row of 1.txt and the next 5 lines after the second row
$d	Sed ' $d ' 1.txt	Delete the last line of 1.txt
/Regular/	Sed '/^[0-9]/d ' 1.txt	Delete a line that starts with a number
！	Sed '/^[0-9]/!d ' 1.txt	Delete rows that do not start with a number
^$	Sed ' ^$ ' 1.txt	Delete empty lines of 1.txt

S replacement sed ' s/old/new/' 1.txt

command	Full example	description
s/old/new/	sed ' s/old/new/' 1.txt	Delete the first old of each row in 1.txt Replace with new
s/old/new/2	Delete the second old of each row in 1.txt Replace with new
s/old/new/g	sed ' s/ol D/new/g ' 1.txt	remove every old in 1.txt for each row replaced by new
s/old//	sed ' s/old//' 1.txt	Delete the first old of each line in 1.txt is replaced with an empty, that is, delete the old
s/old/&s/	sed ' s/old/&s/' 1.txt	Delete the first old of each line in 1.txt replaced by Olds & the string for the previous lookup
4,7s/^/#/	sed ' 4,7s/^/#/' 1.txt	Remove 4-7 lines at the beginning of 1.txt with # that is, bulk add comments
4,7s/^ #an/an/	sed ' 4,7s/^ #an/an/' 1.txt	Delete 4-7 lines in 1.txt with the line beginning with #an remove #

The substitution of s///can be replaced with three other identical symbols, such as s### s&&& s999 can be used to replace the path is often

I/A/C Insertion

Command	Complete Example	Description
Line number I	Sed ' 2i123 ' 1.txt	Insert 123 in front of the second line of 1.txt
Regular I	Sed '/^[0-9]/i123 ' 1.txt	Insert 123 in front of all lines in 1.txt
A	Insert after row	command format and I are the same
C	Replace the row	command format and I are the same

SED Advanced Applications

Command	Complete Example	Description
Line number R	Sed-i ' 2r 2.txt ' 1.txt	Insert the contents of 2.txt after the second line in 1.txt
Line number, line number r	Sed-i ' 2,5r 2.txt ' 1.txt	Insert the contents of 2.txt in the second row to the fifth row after each line in 1.txt
/Regular/R	Sed-i '/^[0-9]/r 2.txt ' 1.txt	Inserts 2.txt of content into each row of rows after the line begins with a number in 1.txt
W	Sed ' 2w 3.txt ' 1.txt	Export the contents of 3.txt to the second row in 1.txt
W	Sed ' 2,5w 3.txt ' 1.txt	Export the contents of 3.txt in the second row to the fifth row in 1.txt
/Regular/R	Sed-i '/^[0-9]/w 2.txt ' 1.txt	A line with a number beginning in 1.txt is exported as a 3.txt content

Use of the SED command in the shell