100 I$ = "INPUT.TXT"
110 O$ = "OUTPUT.TXT"
120 D$ = CHR$(4)
130 M$ = CHR$(13)
140 PRINT D$"VERIFY"I$
150 PRINT D$"OPEN"O$M$D$"CLOSE"O$M$D$"DELETE"O$
160 PRINT D$"OPEN"O$M$D$"OPEN"I$;

170 PRINT M$D$"READ"I$
180 ONERR GOTO 250
190 GET C$
200 POKE 216,0
210 PRINT M$D$"WRITE"O$",B"B
220 IF C$ <> M$ THEN PRINT C$;
230 B = B + 1
240 GOTO 170

250 POKE 216,0
260 IF PEEK(222) <> 5 THEN RESUME
270 PRINT M$D$"CLOSE"I$M$D$"CLOSE"O$