Welcome to the Shell Scripting Tutorial! This guide will help you understand the basics of shell scripting and how to write your own scripts to automate tasks on your computer.

Introduction

Shell scripting is a powerful tool for automating repetitive tasks on a Unix-like operating system. It allows you to write scripts that can perform complex operations using simple commands.

Getting Started

Before you start writing shell scripts, you need to have a Unix-like environment. You can use a virtual machine or install a Unix-like operating system on your computer.

Install a Unix-like Environment

  1. Download a Unix-like distribution from the official website.
  2. Install the distribution on your computer.
  3. Set up a user account and password.

Open a Terminal

Once you have a Unix-like environment, open a terminal. This is where you will write and execute your shell scripts.

Basic Syntax

A shell script is a text file that contains a series of commands. The shell reads these commands and executes them one by one.

#!/bin/bash
echo "Hello, World!"

In this example, the #!/bin/bash line is called a shebang. It tells the shell which interpreter to use to execute the script. The echo command is used to display text on the screen.

Commands

Shell scripts can contain a variety of commands. Here are some common ones:

  • echo: Display text on the screen.
  • ls: List files and directories.
  • cp: Copy files and directories.
  • mv: Move files and directories.
  • rm: Remove files and directories.

Variables

Shell scripts can use variables to store data. Variables are defined using the $ symbol followed by the variable name.

#!/bin/bash
name="John Doe"
echo "Hello, $name!"

In this example, the name variable is set to "John Doe". The echo command displays the text "Hello, John Doe!" on the screen.

Control Structures

Shell scripts can use control structures to control the flow of execution. Here are some common control structures:

  • if/else: Execute a block of code if a condition is true.
  • for: Execute a block of code for a specific number of times.
  • while: Execute a block of code while a condition is true.
#!/bin/bash
if [ $age -gt 18 ]; then
  echo "You are an adult."
else
  echo "You are not an adult."
fi

In this example, the if/else control structure is used to check if the age variable is greater than 18. If it is, the script displays "You are an adult." on the screen.

Functions

Shell scripts can use functions to group related commands together. Functions can be called from anywhere in the script.

#!/bin/bash
say_hello() {
  echo "Hello, World!"
}
say_hello

In this example, the say_hello function is defined and called. It displays "Hello, World!" on the screen.

Best Practices

  • Use meaningful variable names.
  • Comment your code to explain what it does.
  • Use functions to group related commands.
  • Test your scripts regularly.

Learn More

For more information on shell scripting, check out our Advanced Shell Scripting Tutorial.

Shell Scripting