Graphical shell in the context of Abstraction layer

In computing, a desktop environment (DE) is an implementation of the desktop metaphor made of a bundle of programs running on top of a computer operating system that share a common graphical user interface (GUI), sometimes described as a graphical shell. The desktop environment was seen mostly on personal computers until the rise of mobile computing. Desktop GUIs help the user to easily access and edit files, while they usually do not provide access to all of the features found in the underlying operating system. Instead, the traditional command-line interface (CLI) is still used when full control over the operating system is required.

A desktop environment typically consists of icons, windows, toolbars, folders, wallpapers and desktop widgets (see Elements of graphical user interfaces and WIMP). A GUI might also provide drag and drop functionality and other features that make the desktop metaphor more complete. A desktop environment aims to be an intuitive way for the user to interact with the computer using concepts which are similar to those used when interacting with the physical world, such as buttons and windows.

Microsoft Windows was announced by Bill Gates on November 10, 1983, 2 years before it was first released. Microsoft introduced Windows as a graphical user interface for MS-DOS, which had been introduced two years earlier, on August 12, 1981. The product line evolved in the 1990s from an operating environment into a fully complete, modern operating system over two lines of development, each with their own separate codebase.

The first versions of Windows (1.0 through to 3.11) were graphical shells that ran from MS-DOS. Windows 95, though still being based on MS-DOS, was its own operating system. Windows 95 also had a significant amount of 16-bit code ported from Windows 3.1. Windows 95 introduced multiple features that have been part of the product ever since, including the Start menu, the taskbar, and Windows Explorer (renamed File Explorer in Windows 8). In 1997, Microsoft released Internet Explorer 4 which included the (at the time controversial) Windows Desktop Update. It aimed to integrate Internet Explorer and the web into the user interface and also brought new features into Windows, such as the ability to display JPEG images as the desktop wallpaper and single window navigation in Windows Explorer. In 1998, Microsoft released Windows 98, which also included the Windows Desktop Update and Internet Explorer 4 by default. The inclusion of Internet Explorer 4 and the Desktop Update led to an antitrust case in the United States. Windows 98 included USB support out of the box, and also plug and play, which allows devices to work when plugged in without requiring a system reboot or manual configuration. Windows Me, the last DOS-based version of Windows, was aimed at consumers and released in 2000. It introduced System Restore, Help and Support Center, updated versions of the Disk Defragmenter and other system tools.

A "Unix shell" is a shell that provides a command-line user interface for a Unix-like operating system. A Unix shell provides a command language that can be used either interactively or for writing a shell script. A user typically works within a Unix shell via a terminal emulator; however, direct access via serial hardware connections or a Secure Shell are common for server systems. Although use of a Unix shell is popular with some users, others prefer to use a graphical shell in a windowing system, such as those provided in desktop Linux distributions or macOS, instead of a command-line interface (CLI).

A user may have access to multiple Unix shells with one configured to run by default when the user logs in interactively. The default selection is typically stored in a user's profile (for example, in the local passwd file or in a distributed configuration system such as NIS or LDAP). A user may use other shells nested inside the default shell.