Basic usage of the Linux BOC editor sed

Basic usage of the Linux BOC editor sed

How to deal with SED

Reads the file into memory by default----> reads conforming rows into memory that belongs to SED (the mode space of sed) for editing----> display the contents of the post-processing mode space on the screen

Sed: line editor, which does not edit the source file by default, only handles the display of data in the pattern space

How to use

sed [OPTION] ... {Script-only-if-no-other-script} [Input-file].

sed [OPTION]: ' Linesrangecommand ' File ...

[OPTION]:

-N: Silent mode, no longer displays the contents of the mode space by default

-I: Modify source files directly

-E ' linesrangecommand '-e ' linesrangecommand ': Perform multiple operations simultaneously

-F: Specifies a script file that holds multiple SED commands to perform multiple operations simultaneously

-R: Means using an extended regular expression, using only regular expressions by default

Linesrange: Represents a range, that is, which rows

Usage 1:startline,endline such as 1,100 from line 1th to line 100th

Usage 2:/pattern/For example/^redhat/all rows starting with a line beginning with Redhat

Usage 3:/pattern1/,/pattern2/the first line to be matched by PATTERN1,

To the end of the line that was first matched to the pattern

Line: The specified row

Startline,+n N rows Backward from StartLine

Command: Indicates the commands

D: Delete rows that match the criteria

Sed ' 2, $d '/etc/passwd

P: Show rows that match the criteria

Sed '/home/p '/etc/passwd

A \string: Appends a new line after the specified line, with the contents of string

Sed '/^root/a \i am root '/etc/passwd

I \string: Adds a new row before the specified line, with the contents of string

Sed '/^root/i \i am root '/etc/passwd

R file: After you add the entire contents of the FILE1 file to the FILE2 line that matches the criteria,

For merging files

Sed ' 2r FILE1 ' FILE2

W File: Save eligible rows in the FILE2 file to the FILE1 file

Sed ' 2w FILE1 ' FILE2

s/pattern/string/: Find and Replace,

The default is to replace only the first matched string in each row

G: Global Replacement s/pattern/string/g

I: Ignore character case s/pattern/string/i

Sed ' 1,2s/oot/oot/'/etc/fstab

Back reference \ (string\), \1,\2

Sed ' s#\ (L.. e\) #\1r#g ' Test.txt

&: pattern matching such as sed ' s/l. E/&r/g ' Test.txt

After the string that matches the preceding pattern, add

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Basic usage of the Linux BOC editor sed