xdg-icon-resource

xdg-icon-resource {install | uninstall} [--size <size>] [--context <context>] [--theme <theme>] [--fallback] [--noupdate] <icon-file> [<icon-name>]

install
    Installs the specified icon file into the appropriate icon theme directory. Requires the --size option.

uninstall
    Removes the specified icon file from the icon theme directory. Requires the --size option for removal consistency.

--size <size>
    Specifies the nominal size of the icon in pixels (e.g., 24, 48, 128). This is mandatory for both installation and uninstallation to ensure correct placement/removal.

--context <context>
    Defines the context of the icon, guiding its placement within the icon theme. Common contexts include apps (default), mimetypes, actions, places, and devices.

--theme <theme>
    Specifies the name of the icon theme to install or uninstall the icon for. If omitted, the icon is installed/uninstalled for all currently installed themes that support the specified size and context, typically falling back to 'hicolor'.

--fallback
    Allows the icon to be installed directly into the 'hicolor' icon theme directory if the specified theme is not found or no theme is specified. This ensures the icon is always available.

--noupdate
    Prevents the command from automatically updating the icon theme cache after the operation. This can be useful for batch operations where a single update at the end is desired.

<icon-file>
    The path to the icon file (e.g., a .png or .svg file) to be installed or uninstalled.

[<icon-name>]
    An optional name for the icon. If not provided, the base name of <icon-file> (without extension) is used.

xdg-icon-resource is a crucial utility designed for the installation and uninstallation of icon files, making them discoverable by various desktop environments that adhere to the XDG Base Directory Specification and Icon Theme Specification. It's a key component of the xdg-utils package, a collection of scripts aimed at standardizing desktop integration for applications across different Linux desktop environments like GNOME, KDE, and XFCE.

When an icon is installed, this command typically updates the system's icon cache, ensuring that applications and the desktop environment can immediately find and display the new icon without requiring a system restart. This ensures consistent icon management and appearance for user applications.

• Permissions: Installing icons system-wide (e.g., to /usr/share/icons) typically requires root privileges (e.g., via sudo).
• Cache Updates: While xdg-icon-resource usually handles cache updates, in some complex setups or if --noupdate is used, manual updates with tools like gtk-update-icon-cache might be necessary.
• Icon Naming: Ensure icon names are unique and follow conventions to avoid conflicts or unexpected behavior.

xdg-icon-resource is an integral part of the xdg-utils project, which emerged from the FreeDesktop.org (now freedesktop.org) initiative. Its development is rooted in the need for standardized application integration across diverse Linux desktop environments (such as GNOME, KDE, XFCE). The command adheres to the freedesktop.org Icon Theme Specification, providing a consistent and reliable method for developers to manage application icons, ensuring they are correctly placed and discovered by desktop environments, thereby abstracting away desktop-specific differences.

xdg-utils(1), xdg-desktop-menu(1), xdg-mime(1), gtk-update-icon-cache(1)