The shell programming environment with its shell scripts provides function similar to the TSO/E environment with its command lists (CLISTs) and the REstructured eXtended eXecutor (REXX) execs.

The CLIST language is a high-level interpreter language that lets you work efficiently with TSO/E. A CLIST is a program, or command procedure, that performs a given task or group of tasks. CLISTs can handle any number of tasks, from running multiple TSO/E commands to running programs written in other languages. CLISTs can run only in a TSO/E environment. For a discussion of CLISTs, see z/OS TSO/E CLISTs.

The REXX language is a high-level interpreter language that enables you to write programs in a clear and structured way. You can use the REXX language to write programs called REXX programs, or REXX execs, that perform given tasks or groups of tasks. REXX programs can run in any MVS™ address space. You can run REXX programs that call z/OS UNIX services in TSO/E, batch, in the shell environment, or from a C program. For more information about writing REXX programs, see z/OS TSO/E REXX User's Guide, z/OS TSO/E REXX Reference, and z/OS Using REXX and z/OS UNIX System Services.

In the shells, command processing is similar to command processing for CLISTs. You can write executable shell scripts (a sequence of shell commands stored in a text file) to perform many programming tasks. They can run in any dubbed MVS address space. They can be run interactively, using cron, or using BPXBATCH. With its commands and utilities, the shell provides a rich programming environment.