RUNBACK opens a NIL: file handle for both input and output. It may have a
problem if MYCOMMAND tries to open a console * window, I'm not sure about
that. I think Commodore has fixed the RUN command with V1.3 AmigaDOS so
you can use RUN <Nil: >Nil: and close the console window; don't know if
that will work if MYCOMMAND tries to open * though. You may also want to
try the ARP ARUN command with the NOIO switch- …cheath (now using
76004,1766 more often than 74216,2117)