NovaShell

A Unix-like shell built from scratch in C to explore operating system fundamentals, process management, command execution, and shell internals.

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📖 Overview

NovaShell is a custom command-line shell developed from scratch in C as part of a deep dive into systems programming and operating system concepts.

The project aims to recreate the core functionality of modern Unix shells while providing hands-on experience with:

• Process creation and management
• System calls
• File descriptors
• Pipes and redirection
• Signal handling
• Command parsing
• Job control
• Shell architecture

Rather than treating the terminal as a black box, NovaShell explores how shells actually work internally.

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✨ Features

Current Features

• Interactive shell prompt
• Command parsing
• External command execution
• Built-in commands
• Error handling

Planned Features

• Input/Output Redirection (>, <, >>)
• Pipes (|)
• Environment Variables
• Command History
• Tab Completion
• Job Control
• Background Processes (&)
• Signal Handling
• Custom Configuration File
• Shell Scripting Support

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🏗️ Architecture

User Input
     │
     ▼
 Command Parser
     │
     ▼
 Tokenizer
     │
     ▼
 Command Dispatcher
     │
 ┌───┴──────────┐
 ▼              ▼
Built-ins    External Commands
                 │
                 ▼
             fork()
                 │
                 ▼
             execvp()

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📂 Project Structure

NovaShell/
│
├── src/
│   ├── main.c
│   ├── parser.c
│   ├── executor.c
│   ├── builtins.c
│   └── utils.c
│
├── include/
│   ├── parser.h
│   ├── executor.h
│   └── builtins.h
│
├── docs/
│
├── tests/
│
├── Makefile
├── README.md
└── LICENSE

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⚙️ Technologies Used

• C
• GCC
• POSIX APIs
• Linux System Calls
• Make

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🧠 Concepts Explored

NovaShell demonstrates understanding of:

• Operating Systems
• Systems Programming
• Process Management
• Fork-Exec Model
• Inter-Process Communication
• File Descriptors
• Unix Architecture
• Shell Design
• Memory Management

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🚀 Getting Started

Prerequisites

gcc --version
make --version

Clone Repository

git clone https://github.com/YOUR_USERNAME/NovaShell.git
cd NovaShell

Build

make

Run

./novashell

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💻 Example Usage

NovaShell> pwd
/home/user

NovaShell> ls
src include README.md

NovaShell> echo Hello World
Hello World

NovaShell> mkdir test

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📈 Development Roadmap

Phase 1 — Basic Shell

• REPL Loop
• Command Parsing
• Process Execution

Phase 2 — Shell Features

• Pipes
• Redirection
• Environment Variables

Phase 3 — Advanced Features

• Job Control
• Signal Handling
• Command History

Phase 4 — Power Features

• Shell Scripting
• Auto Completion
• Plugin System

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🎯 Learning Goals

This project was created to gain practical experience with:

• Linux Internals
• POSIX Programming
• Process Scheduling
• Shell Architecture
• Systems-Level Software Development

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📚 References

• The Linux Programming Interface
• Advanced Programming in the UNIX Environment
• POSIX Documentation
• Build Your Own Shell (CodeCrafters)
• Linux Man Pages

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🤝 Contributing

Contributions, suggestions, and discussions are welcome.

Feel free to open an issue or submit a pull request.

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📄 License

Licensed under the MIT License.

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