10 DN=PEEK(186)
11 :
12 PRINT"OPEN CMD CHANNEL"
13 OPEN15,DN,15
14 GOSUB87:PRINTDS$:IFNOT(DS=0ORDS=73)THEN82
15 :
16 PRINT"SCRATCH FILE1"
17 PRINT#15,"S0:FILE1"
18 GOSUB87:PRINTDS$:PRINT:IFNOT(DS=1ORDS=62)THEN82
19 :
20 PRINT"SCRATCH FILE2"
21 PRINT#15,"S0:FILE2"
22 GOSUB87:PRINTDS$:PRINT:IFNOT(DS=1ORDS=62)THEN82
23 :
24 PRINT"OPEN FILE1 FOR WRITE"
25 OPEN2,DN,2,"FILE1,S,W"
26 GOSUB87:PRINTDS$:PRINT:IFDS<>0THENCLOSE2:GOTO82
27 :
28 PRINT"WRITE FILE1"
29 FORT=1TO10:PRINT#2,"FILE1 LINE"+STR$(T):NEXT
30 GOSUB87:PRINTDS$:PRINT:IFDS<>0THENCLOSE2:GOTO82
31 :
32 PRINT"CLOSE FILE1"
33 CLOSE2
34 GOSUB87:PRINTDS$:PRINT:IFDS<>0THEN82
35 :
36 PRINT"OPEN FILE2 FOR WRITE"
37 OPEN2,DN,2,"FILE2,S,W"
38 GOSUB87:PRINTDS$:PRINT:IFDS<>0THENCLOSE2:GOTO82
39 :
40 PRINT"WRITE FILE2"
41 FORT=1TO10:PRINT#2,"FILE2 LINE"+STR$(T):NEXT
42 GOSUB87:PRINTDS$:PRINT:IFDS<>0THENCLOSE2:GOTO82
43 :
44 PRINT"CLOSE FILE2"
45 CLOSE2
46 GOSUB87:PRINTDS$:PRINT:IFDS<>0THEN82
47 :
48 PRINT"REN. FILE2 INTO FILE1"
49 REM ** THIS SHOULD UNDER NORMAL
50 REM    CIRCUMSTANCES BE REJECTED
51 REM    BY THE DOS, AS FILE1
52 REM    ALREADY EXISTS!
53 PRINT#15,"R0:FILE1=FILE2"
54 GOSUB87:PRINTDS$:PRINT:IFNOT(DS=0ORDS=63)THEN82
55 :
56 PRINT"OPEN FILE1 FOR READ"
57 OPEN2,DN,2,"FILE1,S,R"
58 GOSUB87:PRINTDS$:PRINT:IFDS<>0THENCLOSE2:GOTO82
59 :
60 PRINT"FILE1 CONTENTS:"
61 INPUT#2,A$:PRINTA$:Q=ST
62 GOSUB87:IFDS<>0THENPRINTDS$:PRINT:CLOSE2:GOTO82
63 IFQ=0THEN61
64 :
65 PRINT"CLOSE FILE1"
66 CLOSE2
67 GOSUB87:PRINTDS$:PRINT:IFDS<>0THEN82
68 :
69 PRINT"OPEN FILE2 FOR READ"
70 OPEN2,DN,2,"FILE2,S,R"
71 GOSUB87:PRINTDS$:PRINT:IFDS<>0THENCLOSE2:GOTO82
72 :
73 PRINT"FILE2 CONTENTS:"
74 INPUT#2,A$:PRINTA$:Q=ST
75 GOSUB87:IFDS<>0THENPRINTDS$:PRINT:CLOSE2:GOTO82
76 IFQ=0THEN74
77 :
78 PRINT"CLOSE FILE2"
79 CLOSE2
80 GOSUB87:PRINTDS$:PRINT:IFDS<>0THEN82
81 :
82 PRINT"CLOSE CMD CHANNEL"
83 CLOSE15
84 END
85 :
86 :
87 DS$="":FORP=-1TO0:GET#15,A$:DS$=DS$+A$:P=ST=0:NEXT:DS=VAL(DS$):RETURN