REXX is a high-level language with extensive facilities for manipulating text. CLISTs are not supported under Enterprise Server so we recommend that you convert your CLISTs to REXX programs.
For more information about the REXX language and how it is used, see the IBM OS/390 TSO/E REXX Reference and IBM OS/390 TSO/E REXX User's Guide.
A REXX program is called an exec. Before running an exec, you need to add the exec to your project, or download it from the mainframe, in the usual way. All REXX execs should start with a comment containing the character string REXX so that they can be distinguished from TSO CLISTs. For example:
/************** REXX **************/
REXX execs should have the file extension .rex.
Optionally, you can define an exec as a member of a partitioned data set (PDS). The DD names SYSEXEC and SYSPROC are normally used for PDSs containing REXX execs. More than one PDS can be allocated to each of these DD names. A SYSEXEC PDS can contain only execs.
MSS interprets an exec as it is run. There are no preceding compilation and linking stages.
MSS supports the use of REXX execs only in the JCL (non-TSO) environment. This can be used for execs that do not need interaction with the user and do not need access to TSO services.