Shell Scripting Basics

1. Introduction

Shell scripting is a powerful way to automate tasks on Unix/Linux systems. It allows users to write scripts that can execute multiple commands, manage file systems, and perform a variety of tasks.

2. What is Shell Scripting?

Shell scripting is a program written for the shell, or command line interpreter, of an operating system. It allows users to combine multiple commands into a single script to automate tasks.

3. Basic Syntax

Shell scripts usually have the following structure:

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

The first line (shebang) indicates which interpreter to use.

4. Variables

Variables store data that can be used later in the script. Here's how to define and use them:

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

5. Control Structures

Control structures allow you to control the flow of your script. Here are some examples:

If-Else Statement

#!/bin/bash
if [ "$name" == "Alice" ]; then
    echo "Welcome back, Alice!"
else
    echo "Who are you?"
fi

Loops

#!/bin/bash
for i in {1..5}; do
    echo "Number $i"
done

6. Functions

Functions are reusable blocks of code. Here's how to define and call a function:

#!/bin/bash
function greet {
    echo "Hello, $1!"
}

greet "Alice"

7. Best Practices

• Use comments to explain your code.
• Keep scripts modular by using functions.
• Test scripts in a safe environment before deploying.
• Use meaningful variable names for clarity.

8. FAQ