💀 Skull Shell

Skull Shell is a feature-rich custom shell written in C, designed for developers and power users who want more control over their command-line experience. Built with modularity and extensibility in mind, Skull Shell provides essential shell functionality with room for advanced features.

---

🚀 Features

Core Functionality

• 🔧 Built-in Commands: cd, exit, echo, clear, pwd, help, and more
• 🖥️ Full External Command Support: Execute ANY system command - ls, cat, grep, ps, git, vim, gcc, make, curl, ssh, and thousands more!
• 🔄 Seamless Command Integration: Automatically falls back to system commands when built-ins aren't found
• 💾 Dynamic Memory Management: Efficient memory allocation and cleanup
• 🎨 Colored Output: Visual feedback with color-coded messages
• 👤 User Context: Displays username and current directory in prompt

Built-in Commands

• cd - Change directory
• pwd - Print working directory
• echo - Display text
• clear - Clear terminal screen
• exit - Exit the shell
• -h - Show help information

External Commands (All System Commands Supported!)

File Operations: ls, cat, touch, cp, mv, rm, mkdir, rmdir, head, tail, chmod, chown, find, locate

Text Processing: grep, sed, awk, sort, uniq, less, more, man

System Monitoring: ps, top, htop, free, df, du, uptime, whoami, uname, id

Network Tools: ping, curl, wget, ssh, scp, ftp, netstat, hostname

Development Tools: gcc, make, git, vim, nano, python, node, npm

Process Management: kill, killall, jobs, bg, fg, nohup, nice

...and literally ANY other command available on your system!

Planned Features

• 🔤 Command Suggestions - Autocomplete and suggest alternatives for mistyped commands
• 🎧 Music Playback - Play local audio files (.mp3, .wav, etc.)
• 🤖 AI Integration - AI-assisted commands using the -ai flag
• 🐞 Script Debugging - Shell script debugging with trace outputs
• 📁 Enhanced File Handling - Simplified file management operations

---

🏗️ Project Structure

shell/
├── images/           # images and ascii art
│   ├── skull.png     # demo image of skull
├── include/           # Header files
│   ├── commands.h     # Command declarations
│   ├── executer.h     # Command execution
│   ├── main.h         # Main includes and definitions
|   ├── memory.h       # commands history
│   ├── parser.h       # Input parsing
│   └── utils.h        # Utility functions
├── src/               # Source files
│   ├── commands.c     # Built-in command implementations
│   ├── executer.c     # Command execution logic
│   ├── main.c         # Main shell loop
|   ├── memory.h       # store and show history
│   ├── parser.c       # Input parsing and tokenization
│   └── utils.c        # Utility functions
├── makefile           # Build configuration
└── readme.md          # This file

---

🔧 Installation & Setup

Prerequisites

• GCC compiler
• Make utility
• Linux/Unix environment

Quick Start

1. Clone or download the project

2. Navigate to the shell directory

   cd SKULL-SHELL

3. Compile the project

   make

4. Run Skull Shell

   ./skull

---

💻 Usage

Once started, Skull Shell provides an interactive prompt showing your username and current directory:

> username /current/directory

Example Commands

# Built-in commands
> pwd                    # Show current directory
> cd /home/user         # Change directory
> echo Hello World      # Print text
> clear                 # Clear screen

# External commands (just like any other shell!)
> ls -la                # List files with details
> cat myfile.txt        # Display file contents
> grep "pattern" *.txt  # Search in files
> ps aux                # Show running processes
> git status            # Git commands work too
> python script.py      # Run Python scripts
> gcc -o program main.c # Compile C programs
> make                  # Build projects
> curl api.example.com  # Make HTTP requests
> ssh user@server       # Connect to remote servers
> exit                  # Exit shell

---

🔍 Technical Details

Architecture

• Modular Design: Separated into distinct modules for parsing, execution, and utilities
• Memory Safe: Dynamic memory allocation with proper cleanup
• Process Management: Fork-exec model for external command execution
• Error Handling: Comprehensive error checking and user feedback

Key Components

• Parser: Tokenizes user input and handles command-line arguments
• Executor: Manages built-in vs external command execution
• Command Handler: Implements core shell commands
• Utils: Provides common utility functions

Memory Management

• Dynamic buffer allocation for input handling
• Automatic memory cleanup after each command
• Reallocation for growing input buffers

---

🛠️ Development

Building

make          # Standard build
make clean    # Clean object files

Code Style

• Clean, readable C code
• Modular architecture with clear separation of concerns
• Comprehensive error handling
• Memory-safe programming practices

---

🤝 Contributing

Contributions are welcome! Areas for improvement:

• Additional built-in commands
• Command history and navigation
• Tab completion
• Configuration file support
• Advanced scripting features

---

📝 License

This project is licensed under the GNU General Public License v3.0.

You are free to use, modify, and distribute this software under the terms of the GPLv3.
See the LICENSE file for full details.

---

Built with ❤️ in C

Skull Shell - Where power meets simplicity