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Overview

BDH Terminal Engine is a lightweight, high-performance terminal multiplexer inspired by tools like tmux and GNU screen, bundled with a built-in, standalone modal text editor.

Architected from the ground up to interact directly with Linux kernel pseudo-terminals (PTY), it manages virtual screen rendering, integrated text editing, and seamless text-based web browsing — right inside your active terminal pane, with zero GUI dependencies.

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Key Features

	Feature
	True Multi-Tab & Multi-Shell Multiplexing — Spawn and manage multiple concurrent /bin/zsh or /bin/bash PTY sessions inside a single terminal window with instant keyboard and mouse switching.
	Built-in & Standalone Modal Text Editor (bdh-edit) — A fully functional, lightweight VT100 text editor. Launch it standalone via bdh-edit <filename> from any shell, or toggle it instantly inside the multiplexer with Ctrl + E — complete with a blinking block cursor (█) and clean alternate-screen isolation.
	Responsive Multi-Platform Capacity — Linux Desktop/Server Mode supports up to 18 concurrent sessions (MAX_SESSIONS 18); Termux/Mobile Mode is optimized for 8 concurrent sessions (MAX_SESSIONS 8) for a clutter-free mobile layout.
	XTerm SGR Mouse Protocol Support — Click directly on any tab in the top badge or footer overlay to switch active sessions instantly, no keyboard required.
	Built-in Token Scanner (Ctrl + K) — Dynamically scan the entire screen for URLs, IP addresses, UUIDs, and file paths, and copy them straight to your clipboard.
	Pure CLI Web Browser Integration — Browse documentation, GitHub repos, and websites inside your active tab, rendered in sharp, glitch-free ASCII/VT100 text mode (Ctrl + B).
	Non-Blocking Asynchronous I/O & Zero-Gap Footer — Powered by a responsive select() event loop with a 10ms timeout for zero input latency, with a permanent, zero-gap Active Sessions Manager footer.
	16KB Anti-Glitch & Anti-Tearing Buffer — A high-capacity 16,384-byte I/O buffer eliminates screen tearing, flickering, and ghosting during heavy stdout bursts or full-screen browser layouts.
	Lightweight & Zero Bloat — Compiles to tiny binaries (bdh-engine and bdh-edit). No X11, Wayland, GTK, or WebKit dependencies — runs flawlessly on servers, SSH sessions, TTYs, Termux, 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.
Session Manager	src/engine/session.c	Initializing, managing, and cleaning up multi-tab lifecycle arrays (8 to 18 sessions).
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.
Text Editor Engine	src/editor/edit.c, src/edit_main.c	Lightweight CLI text editing, row buffer rendering, file I/O, and standalone binary execution.
Mouse Parser	src/engine/mouse.c	Decoding XTerm SGR mouse events (\033[<btn;col;rowM) for instant UI interaction.
Input & Clipboard	src/engine/input.c, src/engine/clipboard.c	Handling raw keyboard shortcuts, mouse events, tab switching, copy/paste, and browser execution.
Token Scanner	src/engine/scanner.c	Extracting structured tokens (URLs, IPs, paths) from the screen buffer into clipboard storage.
Footer & Tabs UI	src/ui/tabs.c, src/ui/statusbar.c	Rendering the zero-gap BDH Active Sessions Manager footer box and status indicators.
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 cleanly on exit.

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⚙️ Prerequisites & Installation

1. Install System Dependencies

Arch Linux / Manjaro

sudo pacman -S --needed gcc make links

Ubuntu / Debian

sudo apt update && sudo apt install -y build-essential links

Termux (Android)

pkg update && pkg install -y clang make links

2. Build & Install the Project

Clone the repository and compile using the included Makefile:

# Clone the repository
git clone https://github.com/BackendDeveloperHub/bdh-terminal-engine.git
cd bdh-terminal-engine

# Build clean executables and install globally
make clean && make && sudo make install

Note for Termux users: Run make clean && make && make install (without sudo).

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Usage

1. Start the Multiplexer Engine

Launch the terminal engine directly from any shell. You can optionally pass a filename to open it immediately in the built-in editor:

bdh-engine [optional_filename.txt]

2. Launch the Standalone Text Editor

Open or create a file using the standalone CLI text editor directly from your standard terminal:

bdh-edit filename.txt

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Controls & Keybindings

Shortcut / Action	Description
Ctrl + A	Switch to the next active Tab / Session sequentially.
Ctrl + E	Toggle the built-in full-screen modal text editor on/off.
Ctrl + B	Launch the CLI Web Browser (links) inside the currently active tab.
Ctrl + K	Trigger the Token Scanner to extract and copy URLs/IPs from the screen.
Ctrl + S	Save the active file (while in Editor Mode).
Ctrl + X	Exit Editor Mode and return to the multiplexer shell.
Ctrl + Q	Safely terminate the engine and restore canonical terminal settings.
Mouse Left Click	Click on any session tab to switch directly to that session.

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Engineering Notes

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 strictly to desktop environments.

By refactoring to a 100% Pure Linux CLI Multiplexer & Modal Editor, the engine achieved:

• Zero Crash Rate — Removed all display server (DISPLAY=:0) and GTK signal errors.
• Server & Mobile Ready — Perfectly functional over headless SSH connections, minimal Arch Linux installations, and Termux mobile environments.
• High Performance — Reduced binary size and memory footprint by over 99%.

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Roadmap

• Session persistence / detach-reattach support
• Configurable keybindings via ~/.bdhrc
• Split-pane layouts within a single tab
• Syntax highlighting in bdh-edit

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Contributing

Contributions, issues, and feature requests are welcome. Feel free to check the issues page or open a PR against the modular source tree above.

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License

Distributed under the GNU GENERAL PUBLIC LICENSE License. See LICENSE for more information.

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Author & Workflow

Prabakaran P — Backend Developer Hub (BDH Linux) Systems Architecture & Engineering Design · AI-Assisted Low-Level C Implementation · Python / FastAPI

A Note on Modern Engineering: This engine was conceptualized, architected, and debugged using an AI-assisted systems engineering workflow — combining human architectural vision with AI-driven code generation for rapid, low-level C development.