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
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

Generating blank files in bulk


Sometimes we may need to generate test cases to test programs that operate on thousands of files. Let's discuss how to generate such files in this recipe.

Getting ready

touch is a command that can create blank files or modify the timestamp of files if they already exist. Let's take a look at how to use them.

How to do it...

  1. A blank file with the name filename will be created using the following command:

    $ touch filename
    
  2. Generate bulk files with a different name pattern as follows:

    for name in {1..100}.txt
    do
      touch $name
    done

    In the preceding code {1..100} will be expanded as a string "1, 2, 3, 4, 5, 6, 7...100". Instead of {1..100}.txt, we can use various shorthand patterns such as test{1..200}.c, test{a..z}.txt, and so on.

    If a file already exists, the touch command changes all timestamps associated with the file to the current time. However, if we want to specify that only certain stamps are to be modified, we use the following options:

    • touch -a modifies only the...