caffeine-indicator

Prevent screensaver activation or system sleep

TLDR

Manually inhibit desktop idleness with a toggle

$ caffeine-indicator

PARAMETERS

--help
    Show help information and exit

--version
    Display version information

--quit
    Quit the running indicator instance (some versions)

caffeine-indicator is a simple, lightweight system tray applet for Linux desktops supporting AppIndicators, such as GNOME Classic, Unity, XFCE, and MATE. It allows users to temporarily prevent the screensaver from starting, the display from blanking, and the system from suspending to RAM.

The applet appears as a coffee cup icon in the notification area (systray). A single click toggles 'caffeine mode' on or off. When active, the icon shows steam rising from the cup, indicating inhibition is engaged. Right-clicking often provides options like setting a timed duration (e.g., 5 minutes to 3 hours), indefinite mode, or quitting the app.

It achieves this by using D-Bus interfaces to request session inhibition from the desktop environment's power manager (e.g., GNOME Settings Daemon, Xfce Power Manager). This simulates ongoing user activity without actual input.

Ideal for watching videos, reading long documents, or running presentations without interruptions. The app is unobtrusive, low on resources, and starts minimized. On modern desktops, it integrates seamlessly but requires panel support for indicators.

Commonly installed via distro packages; source available on Launchpad for building.

CAVEATS

Requires AppIndicator or Ayatana Indicators extension on modern desktops like GNOME Shell (limited Wayland support). Does not persist across reboots; use autostart. Ineffective if power manager is disabled globally.

INSTALLATION

Ubuntu/Debian: sudo apt install caffeine
Fedora: sudo dnf install caffeine
Arch: AUR package caffeine-indicator-git.

AUTOSTART

Add to desktop session startup: run caffeine-indicator on login via Settings > Startup Applications.

CLI ALTERNATIVE

Use companion caffeine command: caffeine toggle for scriptable control without tray.

HISTORY

Developed by Piotr Maliński starting 2011 as a GNOME applet. Popularized in Ubuntu 12.04+ via official caffeine package. Maintained on Launchpad; Python-based with GTK. Evolved with desktop changes, including Ayatana fork for newer environments.