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This article mainly introduces "introduction to the usage of Linux awk". In daily operation, I believe many people have doubts about the introduction of the usage of Linux awk. The editor consulted all kinds of materials and sorted out simple and easy-to-use operation methods. I hope it will be helpful for you to answer the doubts about "introduction to the usage of Linux awk"! Next, please follow the editor to study!

Introduction

Let's first talk about what awk is used for. Awk is a powerful text analysis tool. Compared to grep search and sed editor, awk is particularly powerful in analyzing data and generating reports. To put it simply, awk is to read the file line by line, slice each line with a space as the default separator, and then analyze the cut part.

We can take a look at the version number of awk first.

Usage

The awk command consists of a combination of patterns and actions.

Awk [options] 'pattern {action}' file

The pattern, pattern, can be understood as the pattern matching of sed, which can be composed of expressions or regular expressions between two forward slashes.

An action, action, consists of one or more statements within curly braces, separated by semicolons.

Generally speaking, pattern is who to look for, and action is what to do.

The content processed by awk can come from standard input (= 2). If it matches, the corresponding action is performed ({print $0}). If there is no match, continue to read the next line.

3. Continue to read the next line

4. Repeat 1-3 until the last line is read

Among them, $0 is actually the built-in variable of awk, which represents the current whole row of records. There are many built-in variables in awk. Here we cite a few of them to illustrate that we can borrow these contents to carry out various segmentation operations.

Next, I will give some examples to illustrate.

If you want to split and wrap lines with colons, you can do this

Here, explain again what that BEGIN does.

BEGIN {}: a statement executed before the first line of text is read, generally used to initialize the operation {}: line by line END {}: executed after processing the last line of text, usually used to process the output result

Next, let's talk about the application of regular expressions.

For example, let's match the entire line of records that begin with the character u.

It can also be matched in a specified area, matching a record with the character u at the beginning of the third area

At this point, the study of "introduction to the usage of Linux awk" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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