What is “sleepwatcher” Package?

Monitors sleep, wakeup, and idleness of a Mac
For more details: http://www.bernhard-baehr.de/

Installation

• Open Terminal by pressing command+space then type terminal and hit Enter key.
• Install homebrew first.

  ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)" < /dev/null 2> /dev/null

• Install sleepwatcher.

  brew install sleepwatcher

Now, use sleepwatcher!