⚡ BDH Terminal Engine (bdh-terminal-engine)

A 100% Pure Linux CLI Terminal Multiplexer & Virtual Screen Engine written in Low-Level C.
Built for Backend Developers, Systems Engineers, and CLI Enthusiasts.

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📌 Overview

BDH Terminal Engine is a lightweight, high-performance terminal multiplexer inspired by tools like tmux and GNU Screen. Built from the ground up in C, it interacts directly with Linux kernel pseudo-terminals (PTY), manages virtual screen rendering, and integrates seamless text-based web browsing right inside your active terminal pane—with zero GUI dependencies.

🔥 Key Features

• 🖥️ True Multi-Tab / Session Multiplexing
  Spawn and manage multiple concurrent /bin/bash PTY sessions ([ TAB 1/2 ], [ TAB 2/2 ]) inside a single terminal window with instant keyboard switching.
• 🌐 100% Pure CLI Web Browser Integration
  Browse documentation, GitHub repositories, and websites directly inside your active Bash tab using links—rendered in sharp, glitch-free ASCII/VT100 text mode (Ctrl + B).
• ⚡ Non-Blocking Asynchronous I/O
  Powered by a responsive select() event loop with a 10ms timeout, ensuring zero input latency while handling simultaneous shell output streams.
• 🛡️ 16KB Anti-Glitch & Anti-Tearing Buffer
  Engineered with a high-capacity 16,384-byte I/O buffer to eliminate screen tearing, flickering, and ghosting during heavy stdout bursts or full-screen browser layouts.
• 📦 Lightweight & Zero Bloat
  Compiles to a tiny binary (~40 KB). No X11, Wayland, GTK, or WebKit dependencies required—runs flawlessly on servers, SSH sessions, TTYs, and Linux desktops.

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🏗️ Modular Architecture

The engine is structured into clean, decoupled C modules for maintainability and extensibility:

Module	Source File	Core Responsibility
PTY Engine	src/engine/pty.c	Forking processes and creating pseudo-terminals (pty_spawn) via Linux system calls.
Virtual Screen	src/engine/screen.c, src/ui/panes.c	Detecting real terminal dimensions (ioctl) and maintaining off-screen window buffers.
ANSI / VT100 Parser	src/engine/parser.c	Parsing terminal escape sequences, CSI codes, cursor positioning, and line clearing.
Input & Clipboard	src/engine/input.c, src/engine/clipboard.c	Handling raw keyboard events, tab switching, copy/paste, and browser execution.
Renderer	src/engine/renderer.c	Efficiently flushing the virtual screen state to the physical terminal without flickering.
Terminal Control	src/engine/terminal.c	Managing Linux terminal Raw Mode and restoring canonical settings on exit.

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🛠️ Prerequisites & Installation

1. Install System Dependencies (Arch Linux)

The engine only requires the standard C build tools and the links CLI browser for web support:

sudo pacman -S --needed gcc make links

For Ubuntu/Debian: sudo apt install build-essential links) 2. Build the Project Clone the repository and compile using the included Makefile:

# Clone repository
git clone [https://github.com/BackendDeveloperHub/bdh-terminal-engine.git](https://github.com/BackendDeveloperHub/bdh-terminal-engine.git)
cd bdh-terminal-engine

# Build clean executable
make clean
make

🚀 Usage Start the terminal engine directly from your shell:

./bdh-engine

Default Keyboard Controls / Action Triggers ​Switch Active Tab / Bash Pane: Triggers window switch between Primary and Secondary Bash sessions. ​Open CLI Web Browser (Ctrl + B): Launches links https://github.com/BackendDeveloperHub inside the currently active tab. ​Exit Browser: Press q and confirm with y to return immediately to your shell prompt. ​Exit Engine: Type exit inside all active shell sessions or trigger clean engine termination. ​💡 Engineering Design Decision: Why Pure CLI? ​Early iterations of bdh-terminal-engine experimented with embedded graphical WebKitGTK windows. However, GUI loops (gtk_main_quit) clashed with the low-level PTY select() loop, adding megabytes of bloat and restricting usage to desktop environments. ​By refactoring to a 100% Pure Linux CLI Multiplexer: ​Zero Crash Rate: Removed all display server (DISPLAY=:0) and GTK signal errors. ​Server Ready: Perfectly functional over headless SSH connections and minimal Linux installations. ​High Performance: Reduced binary size and memory footprint by over 99%. ​👨‍💻 Author ​Prabakaran (Backend Developer Hub - BDH Linux) Systems Engineering | Python / FastAPI | Low-Level C | Arch Linux