I wrote a little utility called REXX. It would take a REXX statement and execute it, or if there were no arguments it would simulate a shell environment. I used it alot. I just checked. I still have it. Here's the opening comments:
\n/* Interactive REXX */                                          \n                                                                \n/* written  ??/??/?? by Carl Forde                            */\n/* modified 89/09/07 by Carl Forde - no errortext for NOVALUE */\n/*                                 - display command instead  */\n/* modified 90/02/01 by Carl Forde - remove signal on ERROR   */\n

By changing the filetype it would run as an XEDIT macro. Very handy for debugging XEDIT applications.
wow. makes me all nostalgic.