A prototype for an advanced command language

Abstract

The traditional view of command languages seems to be that, although they are the user's principal interface to an interactive computing environment, they serve merely as a medium for the invocation of other programs and, as such, do not deserve the same level of attention given to programming languages. It seems an axiom that command languages are destined to be opaque, irregular and awkward to use. It is our feeling, however, that because of their central involvement in the use of a computer system, command languages should be powerful, concise and regular; in short, aids to the user in his interaction with the system rather than obstacles to be overcome.In this paper we discuss a prototype for an advanced command language designed to facilitate the use of the computer as a tool by incorporating features that we have found useful in day-to-day experience: uniform invocation of system commands, user programs and command files; easy interconnection of programs, encouraging reusable, functional modules; variables and control structures; and dynamic command line facilities.Many of the concepts found herein are adapted from existing systems, notably the Multics [1] and UNIX [2] operating systems, while the underlying philosophy of computers and programs as tools is inspired by the book Software Tools, by Brian W. Kernighan and P. J. Plauger [3].