🐚 Mini Command-Line Shell (ARM Assembly)

A lightweight, interactive command-line interface (CLI) built entirely from scratch using ARM32 Assembly on Linux.

📖 Overview

This project demonstrates low-level systems programming by implementing a functional shell without relying on standard C libraries (libc). It interacts directly with the Linux kernel using system calls (EABI) to handle input/output, string parsing, and memory management.

It was developed as part of the CO1020: Computer Systems Programming course at the University of Peradeniya (Group 63).

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🎥 Project Demo

See the shell in action!

▶️ Click here to watch the Demo Video

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✨ Features

The shell provides an interactive prompt shell> and supports the following commands:

🛠 Built-in Commands

Command	Description
hello	Prints "Hello World!" to the standard output.
help	Displays the list of available commands.
clear	Clears the terminal screen using ANSI escape codes.
exit	Terminates the shell session gracefully.

🧮 Custom Arithmetic Commands

Command	Usage	Description
hex	hex <number>	Converts a decimal number to Hexadecimal (e.g., hex 255 -> 0xFF).
add	add <num1> <num2>	Adds two decimal integers and displays the result.

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🚀 How to Build & Run

You can run this on a native ARM Linux environment (like a Raspberry Pi) or using QEMU on x86 machines.

1. Prerequisites

• GNU Assembler (as)
• GNU Linker (ld)
• (Optional) qemu-arm if running on a non-ARM PC.

2. Assembly & Linking

Run the following commands in your terminal to compile the source code:

# Assemble the source file
as -o shell.o shell.s

# Link object file to create executable
ld -o shell shell.o