Shell script text three swordsmen sed

Catalog

1 sed Tools

1.1 sed summary

1.2 sed workflow

1.3 sed Command common usage

2 example

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1 sed Tools

1.1 sed summary

sed（Stream EDitor） Is a powerful and simple text analysis conversion tool , Can read text , And edit the text content according to the specified conditions （ Delete 、 Replace 、 add to 、 Mobile, etc ）, Finally, output all lines or only some lines of processing .sed It can also realize quite complex text processing operation without interaction , Widely used in Shell Script , It is used to complete various automatic processing tasks .

1.2 sed workflow

sed The workflow of mainly includes reading 、 Perform and display three processes .

• Read ：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 ,pattern space）.
• perform ： By default , be-all sed Commands are executed sequentially in pattern space , Unless the address of the line is specified , otherwise sed The command will be executed on all lines in turn .
• Show ： Send the modified content to the output stream . After sending the data , Mode space will be cleared .

Before all the contents of the file are processed , The above process will be repeated , Until all content is processed .

  Be careful ： By default, all sed Commands are executed in pattern space , So the input file doesn't change , Unless you're using redirection to store output .

1.3 sed Command common usage

Usually called sed There are two formats for commands , As shown below . among ,“ Parameters ” Refers to the target file of the operation , Use when there are multiple operands , Comma between files “,” Separate ; and scriptfile Represents a script file , Need to use “-f” Option assignment , When the script file appears before the target file , Indicates that the input target file is processed through the specified script file .

Format ： sed [ Options ] ' operation ' Parameters
            sed [ Options ] -f scriptfile Parameters

common sed Command options
-e or --expression=	Indicates that the input text file is processed with instructions, commands or scripts
-f or --file=	Indicates that the input text file is processed with the specified script file
-h or --help	Display help
-n、--quiet or silent	Show only processed results
-i.bak	Edit text file directly
-r、-E	Using extended regular expressions
-s	Treat multiple files as separate files , Instead of a single continuous long file stream

“ operation ” Used to specify the action behavior of file operation , That is to say sed The order of . It is usually used “[n1[,n2]]” Format of operation parameters .n1、n2 It's optional , Represents the number of rows selected for operation , If the operation needs to be in 5～ 20 Between lines , Is represented as “5,20 Action action ”.

Common operations
a	increase , Add a line below the current line to specify
c	Replace , Replace the selected row with the specified content
d	Delete , Delete selected rows
i	Insert , Insert a row above the selected row to specify
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 .
s	Replace , Replace specified characters
y	Character conversion

2 example

Test text

     1	He was short and fat.
     2	He was wearing a blue polo shirt with black pants. 
     3	The home of Football on BBC Sport online.
     4	the tongue is boneless but it breaks bones.12! 
     5	google is the best tools for search keyword.
     6	The year ahead will test our political establishment to the limit.
     7	PI=3.141592653589793238462643383249901429
     8	a wood cross!
     9	Actions speak louder than words
       
       
    10	#woood #
    11	#woooooood 
    12	# AxyzxyzxyzxyzC
    13	I bet this place is really spooky late at night! 
    14	Misfortunes never come alone/single.

example 1

sed When a command is combined with a regular expression , Slightly different format , Regular expression to “/” Surround .

example 1

example 2： Delete eligible text （d）

 

  example 3： Replace eligible text
In the use of sed Command to replace the operation needs to use s（ String substitution ）、c（ The whole line / Replace the whole piece ）、y（ Character conversion ） Command options

 

 

 

  example 4： Migrate eligible text

  In the use of sed When the command migrates qualified text , The following parameters are commonly used .

• H: Copy to clipboard
• g、G: Overlay the data in the clipboard / Append to specified line
• w： Save as a file
• r： Read the specified file
• a： Add the specified content . The specific operation method is as follows
• I,i    Ignore case

 

 

 

example 5 ： Editing files with scripts

Use sed The script stores multiple editing instructions in a file （ One editing instruction per line ）, adopt “-f” Option to call . For example, execute the following command to convert the second 1~6  Line content transferred to 16 After line .