file, e := os.Open(path)
    if e != nil {...}
    defer file.Close()

    fi, e := file.Stat()
    if e != nil {...}
    data, e := syscall.Mmap(int(file.Fd()), 0, int(fi.Size()), syscall.PROT_READ, syscall.MAP_SHARED)
if e != nil {...}

slices := bytes.Split(data, []byte("||"))
for _, s := range slices {
    str := string(s[:])
    fmt.Println(str)
}

slices := bytes.Split(data, []byte("||"))
s := slices[n - 1]
str := string(s[:])
fmt.Println(str)