Today, most of the applications or programs we run on our computers are Graphical User Interface (GUI, pronounced “gooey”) applications. These are typically a window that pops up with a work space, menus, and icons. We can visually see things, “move” them, and click on things. Even the “Finder” or “Explorer” are GUI applications.
This wasn't always the case. When computers were first developed, all user interactions occurred by typing on the keyboard into a text interface.
Linux maintains this older, text-based interface through the terminal emulator, or terminal. By typing into the terminal, we can interact with the shell. The shell is a program that will take our text input and pass it to the kernel. The kernel is the core operating system that will assess how best to carry out each job given the computer's hardware and the task at hand.
Exercise: launch your terminal
For more details, see requirements.
When you first open your terminal, you should get some introductory information about the computer you are on, sometimes some information about when you last logged in, and the prompt. looks like this
If you see this, great! The prompt is telling us that the shell is ready for input. We can type things in and see how the shell responds.
Exercise: Type in some gibberish into the prompt.
Exercise: Type in these commands into the prompt and see what happens:
$ whoami $ hostname $ pwd $ ls $ date