' FB 1.05.0 Win64

Sub removeLines(fileName As String, startLine As UInteger, numLines As UInteger)
  If startLine = 0 Then
    Print "Starting line must be more than zero"
    Return
  End If
  If numLines = 0 Then
    Print "No lines to remove"
    Return
  End If
  Dim fileNum As Integer = FreeFile
  Open fileName For Input As #fileNum
  If err > 0 Then
    Print "File could not be opened"
    Return
  End If
  Dim tempFileName As String = "temp_" + fileName
  Dim fileNum2 As Integer = FreeFile
  Open tempFileName For Output As #fileNum2
  Dim count As Integer = 0
  Dim ln As String
  Dim endLine As UInteger = startLine + numLines - 1
  While Not Eof(fileNum)
    Input #fileNum, ln
    count += 1
    If count >= startLine AndAlso count <= endLine Then Continue While
    Print #fileNum2, ln
  Wend

  If count < startLine Then
    Print "No lines were removed as starting line was beyond end of file"
    Print
  ElseIf count < endLine Then
    Print "Only "; count - startLine + 1; " line(s) were removed as not enough lines to remove more"
    Print
  Else
    Print Str(numLines); " line(s) were removed"
    Print
  End If
  Close #fileNum : Close #fileNum2
  Kill(fileName)
  Name (tempFileName, fileName)
End Sub

removeLines("foobar.txt", 2, 2)
removeLines("foobar.txt", 5, 2)
removeLines("foobar.txt", 3, 4)
Print
Print "Press any key to quit"
Sleep