Book Image

Bash Cookbook

By : Ron Brash, Ganesh Sanjiv Naik
Book Image

Bash Cookbook

By: Ron Brash, Ganesh Sanjiv Naik

Overview of this book

In Linux, one of the most commonly used and most powerful tools is the Bash shell. With its collection of engaging recipes, Bash Cookbook takes you through a series of exercises designed to teach you how to effectively use the Bash shell in order to create and execute your own scripts. The book starts by introducing you to the basics of using the Bash shell, also teaching you the fundamentals of generating any input from a command. With the help of a number of exercises, you will get to grips with the automation of daily tasks for sysadmins and power users. Once you have a hands-on understanding of the subject, you will move on to exploring more advanced projects that can solve real-world problems comprehensively on a Linux system. In addition to this, you will discover projects such as creating an application with a menu, beginning scripts on startup, parsing and displaying human-readable information, and executing remote commands with authentication using self-generated Secure Shell (SSH) keys. By the end of this book, you will have gained significant experience of solving real-world problems, from automating routine tasks to managing your systems and creating your own scripts.
Table of Contents (15 chapters)
Title Page
Copyright and Credits
Packt Upsell
Contributors
Preface
Index

Encrypting/decrypting files from a script


In this section, we are going to learn about OpenSSL. In this section, we are going encrypt and decrypt messages and files using OpenSSL.

Getting ready

Besides having a terminal open, you need to have a basic knowledge of encoding and decoding schemes.

How to do it...

  1. We are going to encrypt and decrypt simple messages. We will use the -base64 encoding scheme. First, we will encrypt a message. Run the following command in the terminal:
$ echo "Welcome to Bash Cookbook" | openssl enc -base64
  1. To decrypt the message, run following command in the terminal:
$ echo " V2VsY29tZSB0byBCYXNoIENvb2tib29rCg==" | openssl enc -base64 -d
  1. Now we are going to encrypt and decrypt files. First, we will encrypt a file. Run the following command in the terminal:
$ openssl enc -aes-256-cbc -in /etc/services -out enc_services.dat
  1. Now we are going to decrypt a file. Run the following command in the terminal:
$ openssl enc -aes-256-cbc -d -in enc_services.dat > services.txt

 

 

How...