What is the use of awk and posix character sets in Linux

What is the use of understanding the awk and posix character sets in Linux? This problem may be often seen in our daily study or work. I hope you can gain a lot from this question. The following is the reference content that the editor brings to you, let's take a look at it!

Awk is a great language, it is suitable for text processing and report generation, its syntax is more common, drawing on some of the essence of some languages, such as C language. It plays a very important role in the daily processing of linux system. It allows you to create short programs that read input files, sort data, process data, perform calculations on input, generate reports, and countless other functions.

Awk posix character set

[: alnum:] literal and numeric characters

[: alpha:] literal character

[: digit:] numeric character

[: graph:] non-empty characters (non-spaces, control characters)

[: lower:] lowercase character

[: cntrl:] control character

[: print:] non-empty characters (including spaces)

[: punct:] punctuation mark

[: space:] all white space characters (new lines, spaces, tabs)

[: upper:] uppercase character

[: xdigit:] hexadecimal numbers (0-9 mai mai f mai F)

Test text:

[root@vm-228-187test] # cat aaa.txt AddddEaaaaa123aaa1233

Awk conditional judgment mode {Action}, conditional operator, ~ matching regular

Uppercase letters exist

[root@vm-228-187test] # cat aaa.txt | awk'$1 ~ / [[: upper:]] / {print $1} 'AddddE

There are numeric characters

[root@vm-228-187test] # cat aaa.txt | awk'$1 ~ / [: digit:] / {print $1} '123aaa1233 Thank you for reading! After reading the above, do you have a general understanding of the use of the awk and posix character sets in Linux? I hope the content of the article will be helpful to all of you. If you want to know more about the relevant articles, you are welcome to follow the industry information channel.