Linux Common Commands--sed

sed 字符流编辑器

SED is the abbreviation for the stream editor (character stream editors), referred to as the Liu Editor.
SED is a powerful tool for manipulating, filtering, and transforming text content. Commonly used features include quick additions and deletions to files, where the two most common functions of the query function are filtering (filtering out the string) to fetch rows (take out the specified line)
Syntax format: sed "options" "sed built-in command character" "Input file"
Attention:
1.sed and subsequent options, commands, and output files, with at least one space between each element

Parameter options:

Parameters	Description
-I.	Modify file Contents directly
-N	Silent mode, only print and SED commands match the content
-R	Extended expressions are supported (default is the basic formal notation French method)
-E	Sed action Edit directly in command-line mode, this is the default option
-F	Writes the action of SED in a file and executes the SED action within filename with –f filename
-V	-V or--version display version information

Action parameter Description:

Parameters	Brief Introduction	Details
A\	New	Insert text below the current line
C\	Replace	Change the selected line to a new text
I\	Insert	Insert text above the current line
D	Delete	Delete a selected row
P	Print	Prints the lines of a template block, usually p is run with the parameter sed-n
S	Replace	Replaces the specified character, such as 1,20 s/old/new/g
G	Replace	Represents a full in-row replacement
Y	Update	Translates a character to another character (but not to regular expressions)
R	File	Read from the target file

Sed meta Character set

Character Set	Description	Case
\^	Start of anchoring lines	such as: ' ^grep ' matches all lines that begin with grep
$	End of Anchor Line	For example: ' grep$ ' matches all rows ending with grep
.	Match a character that is not a line break	such as: ' GR.P ' matches gr followed by an arbitrary character, then P
*	Match 0 or more of previous characters	such as: ' *grep ' matches all one or more spaces followed by the grep line. * Together with any character
[ ]	Matches a character in a specified range	such as: ' [gg]rep ' matches grep and grep
[^ ]	Matches a character that is not within the specified range	such as: ' [^a-fh-z]rep ' matches the beginning of a letter that does not contain a-f and h-z, immediately following the line of the rep
\(.. \)	Tag matching characters	such as: ' (Love) ', Love is marked as 1
&	Save search characters to replace other characters	Like s/love/&/,love this into love
\<	Anchoring the beginning of a word	For example: ' \<grep ' matches a line containing a word that begins with grep
\>	Anchoring the end of a word	For example: ' grep\> ' matches lines that contain words ending with grep
X{M}	Consecutive repeating characters x,m times	For example: ' O{5} ' matches rows containing 5 consecutive O
X{m,}	Continuous repetition of character X, at least m times	For example: ' O{5,} ' matches rows with at least 5 consecutive O
X{m,n}	Repeat character X, at least m times, no more than n times	such as: ' o{5,10} ' matches rows of 5-10 consecutive O
[:d Igit:]	All numbers, equivalent to 0-9	For example: [0-9]---> [[:d igit:]]
[: Lower:]	All lowercase Letters	such as: [A-z]---> [[: Lower:]]
[: Upper:]	All uppercase letters.	such as: [A-z]---> [[: Upper:]]
[: Alpha:]	All the letters	For example: [a-za-z]---> [[: Alpha:]]
[: Alnum:]	Non-special symbols, equivalent to 0-9a-za-z	For example: [0-9a-za-z]---> [[: Alnum:]]
[: Space:]	White space characters	such as: []---> [[: Space:]]
[:p UNCT:]	All punctuation	For example: [^0-9a-za-z]---> [[:p unct:]]

Note: Extended regular expressions must be combined with the-r option

常用：命令 sed 替换用法举例

source file

Example:

Serial Number	instruction	Description
①	Sed-i '/news/c HAPPY ' bak.txt	Line that matches the news character, replaced with HAPPY
Ii	Sed-i ' s#static#stop# ' bak.txt	Replace the static character with the stop character
③	Sed-i '/server/s#68\.1#76\.3# ' bak.txt	Match server word lines, replace 68.1 with 76.3 because the dot has a special meaning all need to be escaped
④	Sed-i ' s#lp#lp#2g ' bak.txt	Replace the next and subsequent on characters in all matching rows with ysg characters
⑤	Sed-i ' s#root#tom#2p ' bak.txt	Replace all occurrences of the second occurrence of the row in the character bin with the Tom character, and reproduce the same row as the matching row
⑥	Sed-i ' s#games#games#2 ' bak.txt	Replace all rows that match the character usr and the third occurrence of usr with the USR character
⑦	Sed-i '/sys/{s#/dev#/log#;s#3#6#g} ' bak.txt	Match the line of the character Sys, replace the character Dev with the log character, and replace 3 with 6
⑧	Sed-i ' s#nologin# (&) #g ' Bak.txt	Enclose nologin in parentheses,& to refer to previously matched characters
⑨	Sed-i ' s/sys:x/#&/g ' bak.txt	Matches the character Sys:x line before adding the # number
⑩	Sed-i '/tcp/s#;# #g ' bak.txt	Matches the line of the character TCP, replaces the semicolon with empty, and can also be used to annotate the # number

After the change

常用：命令 sed 简单变量举例

Reference variable


Note: When the SED command also has a default variable, a syntax error occurs when referring to a variable that you define
Note: When there is no default variable in the SED command, you can change the single quotation mark to double quotation marks when there are default variables in the SED command, the variables that you define need to be enclosed in single quotes, and the statements inside the SED must be quoted

进阶：命令 sed 的高级使用

Case One
The content line that is being manipulated is written to the file


Specify line number Add content

Case Two
Get Domain name information
source files and Result styles
Cat yuming.txt|sed ' s#http:\/\/##;s#\/.*## ' |sort|uniq-c|sort-rn
awk-f/' {print $} ' Yuming.txt|sort-r|uniq-c|awk ' {print ' \ t ', $ $ '

命令参数用法举例

Case One
Parameter-n Example

Note: When you do not add-N, the retrieved rows are repeated two times because SED prints all the rows in the file by default


Note: When using multiple sed edit commands, you need to separate {} with a semicolon

Case Two
Action parameter-s example
Add a book character at the end of a matching line


Add Ysg before the is character


Action parameter-i example

Action parameter-a example

Action parameter-d example

Note: When the-I parameter is not applied, the original text is not modified and the text is written and modified when the-I parameter is used, and the parameter-e means that the SED action is edited directly on the command-line mode, which is the default option
Case Three
An example of a regular expression for SED

Example	Description
Sed ' 5 q '/etc/passwd	Print Top 5 lines
Sed-n ' 1,3p '/etc/passwd	Print 1-3 lines
Sed-n '/r*t/p '/etc/passwd	Print match R has 0 or more lines followed by a T character
Sed-n '/.r.*/p '/etc/passwd	Print matches a line with R and R followed by any character
Sed-n '/o*/p '/etc/passwd	Print o character repeats any time
Sed-n '/o\{1,\}/p '/etc/passwd	Print o repeated occurrences of the word more than once
Sed-n '/o\{1,3\}/p '/etc/passwd	Print o Word repeats once to three times between
Sed-n '/^#/!p '/etc/vsftpd/vsftpd.conf	Prints lines beginning with #, reversed, and the effect of filtering annotations has been reached
Sed-n '/^#/! {/^$/!p} '/etc/vsftpd/vsftpd.conf	Matches lines that begin with #, reverse, and then reverse the line that begins with a space in its result, representing the filter spaces and annotations
Sed-e '/^#/d '-e '/^$/d '/etc/vsftpd/vsftpd.conf	Delete matching empty cells lines that begin with the # sign, SED supports multi-conditional operation on individual files

Linux Common Commands--sed