Korn shell

   An upward-compatible extension to the original Unix shell, written by David Korn and released as part of System V.

   The Korn shell is now the default shell on many Unix systems, particularly those based on System V, including UnixWare and many others.

   Because the Korn shell is an extension of the Bourne shell, everything that works in the Bourne shell also works in the Korn shell.

   The Korn shell also adds the following:

   • Interactive editing of the command line with either vi or emacs

   • Better function definitions providing local variables and the ability to create recursive functions

   • Extensive pattern matching for filenames, similar to regular expressions

   • Several features were adapted from the C shell, including:

   • Command history allowing retrieval and reuse of previous commands

   • Job control and the mechanism for moving jobs between the background and the foreground

   • Aliases for abbreviated command names

   The tilde (Korn shell) used as a shorthand for the name of the home directory

   See also Bash shell; Bourne shell; C shell; Unix shell.