fcitx

fcitx [OPTIONS]

-d, --daemon
    Runs Fcitx in the background as a daemon process.

-r, --replace
    Replaces an already running Fcitx instance with a new one.

-s, --no-systray
    Prevents Fcitx from displaying a system tray icon.

-v, --version
    Displays the Fcitx version information and then exits.

-h, --help
    Shows a help message with available command-line options and exits.

Fcitx (Flexible Context Input X) is a widely used input method framework (IMF) for Unix-like operating systems, primarily Linux. It provides a robust and extensible platform for handling keyboard input, especially for languages that require complex input methods like Chinese, Japanese, and Korean. Instead of direct key-to-character mapping, Fcitx allows users to type sequences of keys which are then processed, converted, and displayed, often leveraging dictionaries and predictive text.

It supports a vast array of input methods (e.g., Pinyin, Wubi, Cangjie, Anthy, Mozc) through its modular architecture and plugin system. Fcitx integrates smoothly with desktop environments like GNOME, KDE, XFCE, and LXDE, typically offering a system tray icon for easy switching between input methods and configuration. Designed to be lightweight, fast, and highly customizable, Fcitx caters to diverse user needs and development requirements. Its plugin-based design facilitates the addition of new features, input methods, and themes, making it a versatile choice for internationalized input.

Proper configuration of environment variables (e.g., XMODIFIERS, GTK_IM_MODULE, QT_IM_MODULE) is crucial for Fcitx to function correctly with graphical applications, especially in X11 environments. Incomplete setup can lead to input issues or Fcitx not being recognized by applications.
While generally stable, compatibility with certain niche applications or specific Wayland setups might require additional configuration or could occasionally present minor quirks.

For Fcitx to integrate seamlessly with various graphical applications, crucial environment variables must be correctly set. These typically include XMODIFIERS=@im=fcitx for X Window System applications, and GTK_IM_MODULE=fcitx along with QT_IM_MODULE=fcitx for GTK+ and Qt applications, respectively. These variables inform the application toolkits about the active input method engine.

Fcitx features a highly modular and plugin-based architecture. This design enables developers to create and integrate new input methods, engines, themes, and various functionalities as independent plugins. This approach makes the framework exceptionally flexible and extensible, allowing for extensive customization without altering the core Fcitx system itself.

Fcitx originated as a simplified Chinese input method for the X Window System. Over time, it expanded into a full-fledged, multi-language input method framework. A significant development was Fcitx4, a major rewrite that introduced a modern, modular, and extensible architecture. Ongoing development focuses on enhancing performance, improving Wayland compatibility, and adding new features, solidifying its position as a leading input solution on Linux.

ibus(1), fcitx-configtool(1), fcitx-remote(1), locale(1)