TRACE ON causes the interpreter to print executed line numbers when it encounters them.
TRACE X sets a limit on the size of line numbers which will be printed out. Only those line numbers less than X will appear. If you are careful and place all your subroutines at the end of the main program, you can display the main structure of the program without cluttering up the trace with the subroutines.
TRACE OFF turns trace off. TRACE is also turned off if an error is reported or you press Escape.
Line numbers are printed as the line is entered. For example,
10 FOR Z=0 TO 2:Q=Q*Z:NEXT 20 END
would trace as
[10] [20] >_
whereas
10 FOR Z=0 TO 2 20 Q=Q*Z:NEXT 30 END
would trace as
[10] [20] [20] [20] [30] >_
and
10 FOR Z=0 TO 3 20 Q=Q*Z 30 NEXT 40 END
would trace as
[10] [20] [30] [20] [30] [20] [30] [40] >_
Syntax
TRACE ON|OFF|<l-num>