Shulou(Shulou.com)06/01 Report--

Today, I will talk to you about the example analysis of awk multi-line merger, which may not be well understood by many people. in order to make you understand better, the editor has summarized the following content for you. I hope you can get something according to this article.

The awknext statement uses: match line by line in a loop. If next is encountered, the current line will be skipped and the following statement will be ignored. And match the next line.

The code is as follows:

The content of text.txt is:

A

B

C

D

E

[chengmo@centos5 shell] $awk 'NR%2==1 {next} {print NR,$0;}' text.txt

2 b

4 d

When the record line number is divided by 2 or more than 1, the current line is skipped. The following print NR,$0 will not be executed either. At the beginning of the next line, the program starts to judge the NR%2 value. When the record line number is: 2, the following statement block will be executed: 'print NR,$0'

Examples of awk next usage:

The code is as follows:

Request:

File: text.txt format:

Web01 [192.168.2.100]

Httpd ok

Tomcat ok

Sendmail ok

Web02 [192.168.2.101]

Httpd ok

Postfix ok

Web03 [192.168.2.102]

Mysqld ok

Httpd ok

You need to change the output format to:

Web01 [192.168.2.100]: httpd ok

Web01 [192.168.2.100]: tomcat ok

Web01 [192.168.2.100]: sendmail ok

Web02 [192.168.2.101]: httpd ok

Web02 [192.168.2.101]: postfix ok

Web03 [192.168.2.102]: mysqld ok

Web03 [192.168.2.102]: httpd ok

Analysis:

The analysis found that the line containing "web" needs to be skipped, and then the content needs to be merged into one line with the following line.

[chengmo@centos5 shell] $awk'/ ^ web/ {Thirty test.txt;} {print T ":\ t" $0;} 'test.txt

Web01 [192.168.2.100]: httpd ok

Web01 [192.168.2.100]: tomcat ok

Web01 [192.168.2.100]: sendmail ok

Web02 [192.168.2.101]: httpd ok

Web02 [192.168.2.101]: postfix ok

Web03 [192.168.2.102]: mysqld ok

Web03 [192.168.2.102]: httpd ok

Next is very convenient in terms of multi-line merging and selective output. You might as well try it when you use it.

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