Shell

In computing, a shell is a user interface for access to an operating system's services. In general, operating system shells use either a command-line interface (CLI) or graphical user interface (GUI), depending on a computer's role and particular operation. Shell

Shell is a user program or it's environment provided for user interaction. Shell is an command language interpreter that executes commands read from the standard input device (keyboard) or from a file. What is Linux Shell ?

Examples of shells:

• Bash
• Power Shell (Windows)

In many of the exercises and videos in our articles we use a shell, more specifically bash. Bash is often run inside a terminal window when shown in videos of this course.

You can use the shell either interactive or non interactive. When using the shell interactively you're invoking commands and programs (shell tools) to perform what you want. Examples of commands are ls to list the content of a directory and mkdir to create a directory. The most common way to use a shell non-interactive is a script.

We provide a reference card for the shell tools covered in this book: Reference card for shell tools.