What the different shells are for

Three different command oriented shells are available for the SCO OpenServer system. You can choose to work with any one of them. The shells are as follows:

The shells

Name	Filename	Features
Bourne Shell	/bin/sh	First shell to be developed. Wildcards, basic command language. Available on the SCO OpenServer system.
C Shell	/bin/csh	Different language syntax from Bourne and Korn shell family (similar to the C programming language). Command history recall (permits reuse of recently issued commands without retyping them). Aliases (the ability to define alternative names for commands). Limited ability to redirect input and output.
Korn Shell	/bin/ksh	Compatible superset of Bourne shell facilities. Command history editing (edit and reissue previously typed commands interactively). Aliases (the ability to define alternative names for commands). Job control (the ability to run processes in the background and manipulate background processes). Extended language syntax (permits more complex scripts to be written). Recommended as the shell of first choice.

The SCO shell is a different type of shell: a menu-driven interface that cannot execute scripts directly. It is discussed in ``Using SCO Shell''.

In this chapter and the next we will be concentrating on the Korn shell: specifically, on those features of the Korn shell that are also available to the Bourne shell. Where additional Korn shell facilities are introduced, they are explicitly identified as such because they are not available under the Bourne shell.

Note that we do not recommend the C shell to new users. C shell syntax is nonstandard, and there are a number of features present in the Bourne and Korn shells that are not present in the C shell.