Learn Linux Shell Scripting - Fundamentals of Bash 4.4

What is Bash?

The most commonly used shell in Linux systems is the Bourne-again shell, or Bash. The Bash shell is based on the Bourne shell, known as sh. But what is a shell?

A shell is, in essence, a user interface. Most often, it is used to refer to a text-based interface, also called a command-line interface (CLI). However, it is called a shell because it can be seen as a shell around the kernel; this means that it applies not just to CLIs, but just as well to graphical user interfaces (GUIs). When we refer to a shell in this book, we are talking about a CLI, and unless stating differently, we're talking about the Bash shell.

The purpose of a shell, both CLI and GUI, is to allow the user to interact with the system. After all, a system ...