In computing, a shell is a command line interpreter which is a piece of software that provides a direct interface for end-users to their operating system. This interface allows users to enter text commands to be executed in a terminal rather than a Graphical User Interface (GUI) with buttons and windows to click on.
Typically, the term refers to an operating system shell which provides access to the services of a kernel. However, the term is also applied very loosely to applications and may include any software that is "built around" a particular component, such as web browsers and email clients that are shells for HTML rendering engines. The name 'shell' originates from shells being an outer layer of interface between the user and the innards of the operating system (the kernel).
Operating system shells generally fall into one of two categories:
- Command line: Command line shells provide a command line interface (CLI) to the operating system where commands can be written and executed directly by a user.
- Graphical: Graphical shells provide a graphical user interface (GUI) which consists of windows, buttons and menus that can be selected by a user.
Using the shell
To use the shell you need to activate a Shell User in your panel. View the Enabling Shell Access article for detailed instructions.
Windows users can use a popular program named PuTTY to interact with their shell. View the PuTTY article for detailed instructions on how to download and configure PuTTY.
You must use some type of terminal to interact with the shell. View the following links for a quick overview of terminals used for Windows, MAC and Linux: