fileName$ = "aFile.txt"
startLine = 100
lineCount = 10

open filename$          for input  as #in
open filename$ ; "_tmp" for output as #out

while not(eof(#in))
   lineNum = lineNum + 1
   line input #in, a$
   if lineNum < startLine or lineNum >= startLine + lineCount then print #out, a$
wend
close #in
close #out