Dim f        As Integer
    Dim fila     As String
    'Iniciamos puntero de array
    i = 0
    'Abrimos Fichero de datos
    f = FreeFile 
    Open "Ruta" For Input As f
    'Procesamos    
    Do While Not EOF(f)
        Line Input #f, fila
        'Buscamos coincidencia de carácteres
        if Instr(lcase(fila), lcase("xxxxx")) <> 0 then 
            i = i+1
            ReDim Preserve Y(i)
            y(i) = fila
        end if 
    Loop
    Close f