You might have access to applications that are written in other programming languages. However, the interfaces to these applications might not be easy to use or remember. Rather than write new applications, you can write CLISTs that provide easy-to-use interfaces between the user and such applications.

A CLIST can send messages to, and receive messages from, the terminal to determine what the user wants to do. Then, based on this information, the CLIST can set up the environment and issue the commands required to invoke the program that performs the requested tasks.