Edit Change And Output A Text File

I use excel to read in an ASCII data file in which every line beginning with H is a header line and lines beginning with S are data line.

I want excel to filter out the header lines and output the file with the data lines only then outputs these in a new file.

I also want it to read the values from column 72 to 75 and subtract 6 from them then output them again to the same new file.

Sub read()
Open "d:/intouch/0502SPSS.LOG" For Input As #1
Dim i As Integer
Dim lines(9999) As String
i = 0
Do While Not EOF(1)
Line Input #1, z
i = i + 1
If Mid(z, 1, 1) = "H" Then
i = i - 1

ElseIf Mid(z, 1, 1) = "S" Then.................................

the problem is that the new file is generated but it is always empty