Copyright (c) 2012-2016 Hyperion Entertainment and contributors.
Many beginners are rather confused by the differences between the terms "AmigaDOS" and "Shell". Some people think they just use the Shell or they are just using AmigaDOS commands in a shell window.
The AmigaDOS software is contained in files stored on the system partition. They are all binaries, either programs directly usable by the user, or libraries and other sets of functions usable by any program or AmigaDOS itself.
You can think of AmigaDOS as a complete system for operating the computer and its peripherals. In order to talk with AmigaDOS the user will use a shell to type commands and get the results from them.
The Shell is a "command line interface" (CLI) that provides a lot of features to interact with the operating system. Simply put, it means that you use an "interface" (in this case a shell window) to send commands to the computer which will use this same interface to display results to your commands.
For historical reasons, you will still find references to the CLI in AmigaOS but this is really a shell that is used everywhere in the system.
Now learn the basics and more complex uses of the AmigaOS shell.
For commands and arguments used in the AmigaOS command line ("CLI"), please see the AmigaDOS pages.