Sed editor

Catalog

introduction ：

One .sed Editor

Two 、sed Editor workflow

2.1 Read

2.2  perform

2.3 Show

2.4 Add

3、 ... and . Command format

Common options ：

Common operations

Four . Use the address

5、 ... and . Delete 、 Replace 、 Insert

Delete

Replace

Insert

summary ：

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introduction ：

At work sed Editors are used a lot , Therefore, for operation and maintenance, it is necessary to master sed The use of editors is also important .

One .sed Editor

• sed Is a flow editor , The stream editor will edit the data stream 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 file .

Two 、sed Editor workflow

2.1 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)

2.2  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 .

2.3 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 .

2.4 Add

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

3、 ... and . Command format

• sed  [ Options ]  ' operation '  Parameters
• sed  [ Options ]  -f  scriptfile    Parameters

Common options ：

• -e or - -expression=         # Indicates that the input text file is processed with the specified command , Only one operation command can be omitted , One It is generally used when executing multiple operation commands
• 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   # prohibit sed Editor output , But you can p Command to complete the output
• -i    # Modify the target text file directly

Common operations

 operation 	      explain 
s	 Replace , Replace specified characters 
d	 Delete , Delete selected rows 
a	 increase , Add a line below the current line to specify 
i	 Insert , In the selected line , Insert a specified line above 
c	 Replace , Replace the selected row with the specified content 
y	 Character conversion , The character length before and after conversion must be the same 
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 
=	 Print line number 
l ( A lowercase letter L)	 Print text in the data stream and unprintable ASCII character ( Like the terminator $、 tabs \t)

Four . Use the address

sed The editor has 2 Address mode ：1. Represent row intervals in numerical form

                                            2. Use text mode to filter travel

5、 ... and . Delete 、 Replace 、 Insert

Delete

• sed  'd'  1.txt  # Delete all
•  sed  '$d'  1.txt  # Delete last line
• sed  '2,5d' 1.txt  # Delete 2-5 That's ok

Replace

Format ： Line scope     s/ Old characters     / New character     / Replace mark

4 Two alternative markers ：1. Numbers ： Indicates where the new string will replace the match

                        2.g： Indicates that the new character will replace all matches

                       3.p： Print the line that matches the replace command , And -n Use it together

                       4.w file ： Write the result of the replacement to a file

Insert

• sed  '1a    520'  1.txt   # stay 1.txt Insert... After the first line of the file 520
• sed  '1i    520'  1.txt   # stay 1.txt Insert before the first line of the file 520
• sed  '/r/etc/resolv.conf'   1.txt    # stay 1.txt Insert text after the first line in the file

summary ：

sed The use of is very common 、 It's also important. , Therefore, as an operation and maintenance engineer, you must master sed The usage and theory of .