Caffeine prevents an automatic screensaver or going into standby/sleep/hibernate, useful for presentations or playing video. It works by simulating a keypress once every 59 seconds, so your PC thinks you’re still working at the keyboard. Double-clicking the program icon “empties” the coffee pot and temporarily disables the program, while doing this a second time re-enables it.
Other command-line arguments for more functions are present on the web site.
