Book Image

Linux Shell Scripting Cookbook, Second Edition - Second Edition

Book Image

Linux Shell Scripting Cookbook, Second Edition - Second Edition

Overview of this book

The shell remains one of the most powerful tools on a computer system — yet a large number of users are unaware of how much one can accomplish with it. Using a combination of simple commands, we will see how to solve complex problems in day to day computer usage.Linux Shell Scripting Cookbook, Second Edition will take you through useful real-world recipes designed to make your daily life easy when working with the shell. The book shows the reader how to effectively use the shell to accomplish complex tasks with ease.The book discusses basics of using the shell, general commands and proceeds to show the reader how to use them to perform complex tasks with ease.Starting with the basics of the shell, we will learn simple commands with their usages allowing us to perform operations on files of different kind. The book then proceeds to explain text processing, web interaction and concludes with backups, monitoring and other sysadmin tasks.Linux Shell Scripting Cookbook, Second Edition serves as an excellent guide to solving day to day problems using the shell and few powerful commands together to create solutions.
Table of Contents (16 chapters)
Linux Shell Scripting Cookbook
About the Authors
About the Reviewers

Sorting unique and duplicates

Sorting is a common task that we can encounter with text files. The sort command helps us to perform sort operations over text files and stdin. Most often, it can also be coupled with many other commands to produce the required output. uniq is another command that is often used along with a sort command. It helps to extract unique (or duplicate) lines from a text or stdin. This recipe illustrates most of the use cases with sort and uniq commands.

Getting ready

The sort command accepts input as filenames, as well as from stdin (standard input) and outputs the result by writing into stdout. The same applies to the uniq command.

How to do it...

  1. We can easily sort a given set of files (for example, file1.txt and file2.txt) as follows:

    $ sort file1.txt file2.txt > sorted.txt


    $ sort file1.txt file2.txt -o sorted.txt
  2. For a numerical sort, we can use:

    $ sort -n file.txt
  3. To sort in the reverse order, we can use:

    $ sort -r file.txt
  4. For sorting by months (in the order...