🐱 MShell

A modern, feature-rich POSIX-compliant shell implementation written in C++23.

✨ Features

• Smart Tab Completion - Trie-based command indexing with prefix matching
• Command History - Navigate with arrow keys (↑/↓)
• I/O Redirection - Full support for >, >>, 2>, 2>>, 1>, 1>>
• Raw Terminal Mode - Real shell-like experience
• Finite State Machine Tokenizer - Robust parsing with quote and escape support
• Built-in Commands - echo, pwd, cd, exit, type, history, mshell
• PATH Discovery - Auto-completion for system commands

🚀 Quick Start

# Clone the repository
git clone https://github.com/yourusername/shell-cpp.git
cd shell-cpp

# Build and run
./build.sh

🔧 Building Locally

Prerequisites:

• C++23 compatible compiler (GCC 13+ or Clang 15+)
• CMake 3.13+
• vcpkg (included as submodule)

Build Steps:

# Initialize vcpkg submodule
git submodule update --init --recursive

# Build with CMake
mkdir build && cd build
cmake .. -DCMAKE_TOOLCHAIN_FILE=../vcpkg/scripts/buildsystems/vcpkg.cmake
make

# Run the shell
./shell

🎯 Usage Examples

$ echo "Hello, World!"          # Built-in commands
$ ls -la                        # External commands  
$ echo "output" > file.txt      # I/O redirection
$ cat file.txt 2> error.log     # Error redirection
$ his<TAB>                      # Tab completion → history
$ <↑>                          # Command history

🔮 Future Plans

• Signal handling (Ctrl+C, Ctrl+Z)
• Syntax highlighting
• Pipe support (|)
• Job control (&, jobs, fg, bg)
• Configuration file support
• Plugin system for custom commands

📁 Project Structure

src/
├── main.cpp          # Terminal management & main loop
├── tokenize.cpp      # FSM-based tokenizer
├── builtins.cpp      # Built-in command implementations
├── search.cpp        # Trie-based command completion
├── history.cpp       # Command history management
└── util.cpp          # System utilities & PATH handling

🛠️ Technical Highlights

• Finite State Machine tokenizer for robust command parsing
• Trie data structure for efficient command completion
• Raw terminal control using termios for real-time input
• Process management with fork/exec for external commands
• File descriptor manipulation for I/O redirection
• Modern C++23 features with memory-safe design patterns

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Contributions are Welcome !