Modules: Providing a Flexible User Environment

Typically users initialize their environment when they log in by setting environment information for every application they will reference during the session. The Modules package is a database and set of scripts that simplify shell initialization and lets users easily modify their environment during the session. The Modules package lessens the burden of UNIX environment maintenance while providing a mechanism for the dynamic manipulation of application environment changes as single entities. Users not familiar with the UNIX environment benefit most from the single command interface. The Module package assists system administrators with the documentation and dissemination of information about new and changing applications. This paper describes the motivations and concepts behind the Modules package design and implementation. It discusses the problems with modifying the traditional user environment and how the Modules package provides a solution to these problems. Both the user’s and the system administrator’s viewpoint are described. This paper also presents the reader with a partial implementation of the Modules package. Sample C Shell and Bourne Shell scripts with explanations are used to describe the implementation. Finally, an example login session contrasts the traditional user’s environment with one that uses the Modules package.