P.S.
SET variables can be assigned their values before // EXEC PROC=, and their values used inside those PROCs, unless the PROC is using its own parameters with the same names.
/* rexx */
parse arg prm /* i.e. 'DSN1;-TERM UTILITY (AI.AIZ040)' */
do n=1 to 99 while prm<>''
parse var prm line.n';'prm
end
line.0=n-1
"execio" line.0 "diskw parm (stem line. finis)"