5-2-rhel6.3-sed Stream Editing Tool (Red Hat Enterprise Linux Server6.3) @ Tree Bag Wandering

Sed stream editing tools (most of which are located in behavioral operating units)

SED does not directly modify the source file by default, but instead copies it to a buffer called pattern space through a pipeline or a file read, and its instructions are completed and printed on the screen in this pattern space.

Syntax format:

The above refers to the positioning in the end of the unit, then the line is defined as the address, that is, manipulating the object

The scope of the address has a centralized format

N# specifying a unique line number

Two or #Specify starting from line 1, spaced 2 is 1,3,, 5, by analogy


$ #Specify the last line


/ Regular Expression / # Matches the operand of the regular expression

\ a Regular expression a # matches regular expressions between \ a and a

3,5 # matches 3-5 rows


1, + 10 # matches 1 and 1 followed by 10 lines of content

sed [options [Script instruction] [input file]

Option: -n # silent output, does not print the contents of the mode space, is automatically printed by default

-E Script # allows multiple script directives to be executed

-f # reading instructions from a file

-l # output of the length of the president

-r # Extended Regular Expressions

-i # Modifying source files directly

directive: A (Append) #Append

D (delete) #Delete

s (substitution) #Replace

C # changes

y# Replace by character

p# Printing

q# exit

i# Insertion

l# Printing (non-printing characters displayed)

l# printing (displaying print characters)

r# read in file contents

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Example: Append "This is a example" after the first line

[[Email protected] ~]# SED "1a This is a example"/opt/fstab_mrpan

Example: Append "This is a example" before line 6th #注意源文件发生改变了

[Email protected] ~]# Sed-i "6i This is a example"/opt/fstab_mrpan

650) this.width=650; "src=" http://s3.51cto.com/wyfs02/M02/70/F6/wKiom1XB0lbzqctjAACbL0Tl_8s565.jpg "/>

Example: Replace command

[[Email protected] ~]# sed "s/defaults/mr.pan/g"/opt/fstab_mrpan

[Email protected] ~]# sed-i "3s/fstab/fstab_mr.pan/g"/opt/fstab_mrpan

Example: Changing a command

[[Email protected] ~]# sed "/pan/c exit"/etc/passwd | More

Example: using regular expressions

Match line units that contain fstab

[Email protected] ~]# Sed-i "/fstab/a This is a example"/opt/fstab_mrpan

[Email protected] ~]# sed-n "/^$/d"/opt/fstab_mrpan

You can use the E F or delimiter semicolon when you need to execute multiple instructions, but you can also use the-f file, which is easy to modify and not error-prone.

Example: Delete a row containing example, replace all 0 for 1

(1), [[email protected] ~]# sed-e "/example/d"-E "s/0/1/g"/opt/fstab_mrpan

(2), [[email protected] ~]# sed "/example/d;s/0/1/g"/opt/fstab_mrpan

(3), as shown:

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(4), write a file

650) this.width=650; "src=" http://s3.51cto.com/wyfs02/M01/70/F6/wKiom1XB0lezRbYgAAB8cMZOTTs253.jpg "/>

Example: File contents are as follows

650) this.width=650; "src=" http://s3.51cto.com/wyfs02/M02/70/F3/wKioL1XB1E-yWa6HAADVUpZT9Bk272.jpg "/>

650) this.width=650; "src=" http://s3.51cto.com/wyfs02/M00/70/F6/wKiom1XB0lfRLp7fAABIQfUU_-c306.jpg "/>

650) this.width=650; "src=" http://s3.51cto.com/wyfs02/M02/70/F6/wKiom1XB0lew6SsKAAFB_3U5DN0865.jpg "/>

Here's a summary of the SED format:

[Match line] {

Command 1

Command 2

Command 3

}

Example: Delete a space in a file

First step: Create a space environment

[Email protected] ~]# Cat/etc/group >> sed_d2_example

[Email protected] ~]# sed g/sed_d2_example i

Step two: Write the file vim sed.sh as shown below

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Step three: [[email protected] ~]# sed-f./sed.sh./sed_d2_example i# Remove spaces

Example: inserting a blank line on a matching line

[[Email protected] ~]# sed "/sshd/{x;p;x;}"/etc/group

Example: inserting a blank line under a matching line

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5-2-rhel6.3-sed Stream Editing Tool (Red Hat Enterprise Linux Server6.3) @ Tree Bag Wandering