c-hjkl-py

Lightweight Python tool to remap Ctrl + H/J/K/L to arrow keys and CapsLock to ESC — optimized for Dvorak users.

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✨ What It Does

• Maps Ctrl + H to ←, Ctrl + J to ↓, Ctrl + K to ↑, Ctrl + L to →
• Remaps CapsLock to ESC
• Works by intercepting input events and forwarding them through a virtual keyboard
• Designed for Dvorak layout, but easily adaptable

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🤔 Why This Exists

I was using stewartpark/c-hjkl, but after reinstalling Arch Linux, it stopped working for my laptop’s built-in keyboard.

Since I’m not super familiar with Rust and wanted to debug it quickly, I reimplemented the core logic in Python.

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⚙️ How It Works

1. Detects connected keyboards on your system.
2. Listens to their input events using evdev.
3. Creates a virtual device using the uinput module.
4. Translates your key combos and emits remapped events.

Your system receives input from the virtual keyboard instead of the physical one.

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🔧 Can I Customize Keys?

Yes.

To change the key used for triggering remaps (e.g., Ctrl to something else), edit:

# In src/keyboard_handler.py
KEY_LEFTCTRL = 29  # Change this to your desired key

You can also modify other mappings by tweaking the keycode logic in the same file.

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🛡️ Security Notice

⚠️ IMPORTANT: Run and install this tool as the root user only.

Since it runs with elevated privileges and hooks low-level input devices, make sure that:

• Your normal user cannot modify the project files.
• You clone it into a protected directory (e.g., /opt/).

This prevents privilege escalation in case your user account gets compromised.

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🚀 Installation

sudo su
cd /opt
git clone https://github.com/AlpSha/c-hjkl-py.git
cd c-hjkl-py
./install.sh

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🧱 Dependencies

• Python 3
• evdev Python package
• uinput kernel module (make sure it’s loaded)

Install evdev via pip if needed:

pip install evdev

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🧪 Tested On

• Arch Linux (x86_64)
• Dvorak layout

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🧩 TODO / Future Plans

• Layout support toggle
• GUI tray icon
• Hotkey customization via config file

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📜 License

MIT

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Made with caffeine and key rage by Alp.