Caffeine is a tool used to temporarily prevent the activation of the screensaver / lock screen / sleep mode when using full-screen windows. The application is useful when using video players that don't do this automatically, when listening to music while not using the computer, etc.
With the 2.7.x release, Caffeine stopped using an Ubuntu AppIndicator, a feature that many considered essential, resulting in various forks being developed.
Well, there's no need for that any more because the latest Caffeine 2.8, released today, brings back the Ubuntu AppIndicator, which allows to inhibit the desktop idleness manually. You can continue to use Caffeine without an indicator: simply launch "Caffeine" from the menu / Dash. If you want to use the indicator, launch "Caffeine Indicator" instead:
Caffeine 2.8 also brings some fixes which should get the app to work with most desktop environments again (2.7 only worked in a few, according to the Caffeine developers) as well as a new feature: a new command called "caffeinate" which adds the ability to inhibit desktop idleness for the duration of a particular command - to use it, simply type:
and Caffeine won't allow the desktop to become idle for the duration of "COMMAND".
Install Caffeine 2.8
The official Caffeine PPA was updated with the latest Caffeine 2.8 only for Ubuntu 14.04 / Linux Mint 17 and 17.1 and derivatives. To add the PPA and install Caffeine 2.8, use the following commands:
sudo add-apt-repository ppa:caffeine-developers/ppa sudo apt-get update sudo apt-get install caffeine
Ubuntu 14.10 and 15.04: you can grab the Caffeine 2.8 deb from HERE. Note: make sure that libappindicator3-1 and gir1.2-appindicator3-0.1 are installed ("sudo apt-get install libappindicator3-1 gir1.2-appindicator3-0.1") because the package is currently missing these dependencies and the Caffeine indicator will fail to start without them (I reported the bug HERE).
Ubuntu 12.04: Unfortunately, Caffeine 2.8 doesn't work in Ubuntu 12.04. However, you can use the PPA above to install an older version (2.4.1).
If you're not using Ubuntu / Linux Mint and derivatives, you can download the Caffeine source code via Launchpad (BZR).
Important note: Caffeine is set to start automatically on login, but only the command line version so if you want to start the indicator on login, you'll have to add "caffeine-indicator" to your startup applications.
Report any bugs you may find @ Launchpad.