REstructured eXtended eXecutor language (REXX) is a high-level interpretive language that enables you to write programs in a clear and structured way. You can write programs in the REXX language, called execs, to perform given tasks or groups of tasks. You can execute REXX execs in TSO/E, ISPF, and in any non-TSO/E address space. REXX execs cannot be invoked authorized in the foreground or the background.

In addition to REXX exits, TSO/E supplies replaceable routines you can use to customize REXX processing and specifically, system services. The following topics give you an overview of the language processor environments and the replaceable routines. For complete information about the language processor environments and the replaceable routines, see .