Shell Script Programming

Explanation

Here is a concise breakdown of the Bash calculator script:

1. Purpose

This program is a simple command-line calculator. It takes two numbers and an operator from the user, then uses a case statement (Bash's version of a switch-case) to perform and display the correct arithmetic calculation.

2. Key Concepts

• User Input (read -p): Prompts the user for data and stores it in variables.
• Control Flow (case ... esac): Evaluates a variable against multiple patterns (operators) to execute specific code blocks.
• Arithmetic Expansion ($((...))): Performs mathematical calculations in Bash.
• Conditional Check (if/else): Prevents errors by checking for division by zero.
• Escaping Wildcards (\*): Uses a backslash so Bash treats * as a literal multiplication symbol rather than a pattern wildcard.

3. Code Walkthrough

1. Getting Input:
   • Prompts the user to enter num1 and