this was used to generate a list of difference between one algol file
with sequential numbering on left, &
another file with no numbering on left

10 input fame$
20 open fame$ as 1
22 open "out" for output as 2
25 linput #1,a$:linput #1, a$:linput #1,a$
30 while not eof(1)
40 linput #1, c$
45 a = val(c$): a$ = c$
50 if a <> b + 100 then 200
60 b = a
70 b$ = a$
80 wend
90 end
200 print #2, "line missing at ";a,b;" line was"
210 ? #2,  b$
220 ? #2, "and"
230 ? #2, a$
240 goto 60