Deleting every 2nd and 3rd line in a from a Text file

I am currently开发者_如何转开发 looking for a way of deleting every (n)th and (n)th line in a txt file. For example every 2nd and 5th line. Is there a way of doing this with a script or with C#?

This code is in VB.NET but I believe this will do what you want?

    Dim sr As streamreader = Nothing
    Dim sw As StreamWriter = Nothing
    Dim LineString As String = ""
    Dim LineNum As Integer = 0
    Try
        sr = New StreamReader("C:\scratch\input.txt")
        sw = New StreamWriter("c:\scratch\output.txt")
        Do Until sr.EndOfStream
            LineString = sr.ReadLine
            LineNum += 1

            If LineNum Mod 2 = 0 Then
                'don't output 2nd line
            ElseIf LineNum Mod 5 = 0 Then
                'don't output 5th line
            Else
                'write it 
                sw.WriteLine(LineString)
            End If
        Loop
    Catch ex As Exception
        MsgBox("Error - " & ex.Message)
    Finally
        If Not IsNothing(sr) Then sr.Close()
        If Not IsNothing(sw) Then sw.Close()
    End Try