Introduction

Goal: This tutorial aims to teach you how to automate daily system tasks using shell scripts. By the end of this tutorial, you will be able to write scripts to automate repetitive tasks, saving you time and reducing the possibility of errors.

Learning Outcomes:
- Understand the basics of Shell Scripting
- Write your own Shell Scripts
- Automate daily tasks using Shell Scripts

Prerequisites:
- Basic knowledge of Linux command line
- Access to a Linux-based system (e.g., Ubuntu)

Step-by-Step Guide

Understanding Shell Scripting

Shell scripts are a series of commands that are executed in order from top to bottom. They are incredibly useful for automating tasks on a Linux system.

Writing Your First Shell Script

Let's begin by writing a simple shell script. Use a text editor such as nano or vi to create a new file. For example:

$ nano myscript.sh

In this file, write the following:

#!/bin/bash
# This is a comment
echo "Hello, world!"

The first line tells the system that this is a Bash script. The second line is a comment, and the third line prints "Hello, world!" to the console.

Save and close the file. To make the script executable, use the chmod command:

$ chmod +x myscript.sh

Now, you can run the script:

$ ./myscript.sh

You should see "Hello, world!" printed to the console.

Code Examples

Let's look at some practical examples of shell scripts.

Example 1: Automating System Updates

This script will automatically update your system. It's useful for system administrators who need to keep multiple machines updated.

#!/bin/bash
# This script updates the system
echo "Starting system update"
sudo apt-get update        # Fetches the list of available updates
sudo apt-get upgrade -y    # Installs updates
echo "System update complete"

Example 2: Automating Backups

This script will create a backup of a directory.

#!/bin/bash
# This script creates a backup of my_project
echo "Starting backup"
tar -czf my_project.tar.gz /path/to/my_project   # Creates a tarball of my_project
echo "Backup created"

Summary

In this tutorial, we learned about shell scripting and how to automate tasks using shell scripts. You now know how to create, modify, and run your own scripts, and have seen practical examples of system updates and backups.

Practice Exercises

1. Write a script that prints the current date and time.
2. Write a script that checks if a file exists. If it does, print "File exists". If not, print "File does not exist".
3. Write a script that monitors the size of a directory and sends an email if it exceeds a certain size.

Next Steps

Continue practicing writing your own scripts. Look for daily tasks that you can automate. The more you practice, the more proficient you'll become.

Additional Resources

• Advanced Bash-Scripting Guide
• ShellCheck - a useful tool for checking your shell scripts for errors.