Termux is an Android terminal emulator and Linux environment app that provides a full command-line experience on Android devices. It combines a VT100/xterm-compatible terminal emulator (written in Java with JNI for PTY creation) with a bootstrap Linux environment containing common command-line tools (bash, ssh, compilers, etc.). The architecture is modular: a core terminal-emulator library handles escape sequences, Unicode, sixel graphics, and session management; a terminal-view module provides the Android View widget for rendering; a termux-shared library contains reusable utilities for file I/O, IPC, preferences, error handling, and shell execution; and the app module ties everything together with activities, services, and a plugin ecosystem (API, Float, Tasker, Widget, etc.). Key entry points include TermuxActivity (main UI), TermuxService (foreground service managing sessions), RunCommandService (plugin command execution), and TermuxInstaller (bootstrap setup). External dependencies include Android SDK (target 28, compile 36), Gradle, NDK for native code, and libraries like Apache Commons IO, Guava, and Markwon for markdown rendering.