If you deal with customers and need to collect information about their environment, you need to enter "man sysdiagnose" into a Terminal.

This project is a simple command line interface designed to easily operate ffmpeg the “hyper fast video and audio encoder” to facilitate the encoding of videos in Apple iPod and Sony PSP compatible formats on a Linux system.

You have Linux installed and running. The GUI is working fine, but you are getting tired of changing your desktop themes. You keep seeing this "terminal" thing. Don't worry, we'll show you what to do.