What is “unarj” Package?

ARJ file archiver
For more details: http://www.arjsoftware.com/files.htm

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 unarj.

  brew install unarj

Now, use unarj!