REXX is a programming language that is extremely versatile. Aspects such as common programming structure, readability, and free format make it a good language for beginners and general users. Yet because the REXX language can be intermixed with commands to different host environments, provides powerful functions and has extensive mathematical capabilities, it is also suitable for more experienced computer professionals.

The TSO/E implementation of the REXX language allows REXX execs to run in any MVS™ address space. You can write a REXX exec that includes TSO/E services and run it in a TSO/E address space, or you can write an application in REXX to run outside of a TSO/E address space. For more information, see Using REXX in TSO/E and Other MVS Address Spaces.

There is also a set of z/OS UNIX extensions to the TSO/E Restructured Extended Executor (REXX) language which enable REXX programs to access z/OS UNIX callable services. The z/OS UNIX extensions, called syscall commands, have names that correspond to the names of the callable services that they invoke—for example, access, chmod, and chown. For more information about the z/OS UNIX extensions, see z/OS Using REXX and z/OS UNIX System Services.