Operating system shell

An operating system shell is a shell for an operating system; it is a program that presents an interface to various operating system functions and services. The shell is so called because it is 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 and graphical. Command line shells provide a command line interface (CLI) to the operating system, while graphical shells provide a graphical user interface (GUI).

The relative merits of CLI- and GUI-based shells are often debated. CLI proponents claim that certain operations can be performed much faster under CLI shells than under GUI shells (such as moving files, for example). However, GUI proponents advocate the comparative usability and simplicity of GUI shells. The best choice is often determined by the way in which a computer will be used. On a server mainly used for data transfers and processing with expert administration, a CLI is likely to be the best choice. On the other hand, a GUI would probably be more appropriate for a computer to be used for secretarial work.

List of shells

Graphical (GUI) shells

• Microsoft Windows environments:
  • Windows Explorer
  • Litestep
  • Geoshell
  • BB4Win
  • Emerge Desktop
• Macintosh Finder
• X Window System-based environments (primarily for Unix):
  • KDE
  • GNOME
  • Blackbox
  • CDE
• DOSSHELL

Text (CLI) shells

• Unix shells:
  • Bourne shell (sh)
    • Almquist shell (ash)
    • Bourne-Again shell (bash)
  • C shell (csh)
    • TENEX C shell (tcsh)
  • Korn shell (ksh)
  • scsh (Scheme Shell)
  • Z shell (zsh)
• rc shell (rc) - shell for Plan 9 and Unix
• command.com - shell for DOS
• cmd.exe - shell for OS/2 in text mode and for Windows NT
• 4DOS, 4OS2, 4NT - shells for DOS, OS/2, and Windows NT written and sold by JP Software

See also

• MS-DOS Shell
• Unix shell