Beautiful pipelines in Elixir

Even though I have used Elixir for several years now it still
amazes me how much you can achieve with a single pipeline in Elixir language. The other day I had to find the total size of the files in a given dir. I thought of just parsing the output of the ls -l command and then adding up all the file sizes to get the total. Here is what I ended up with.

"ls -l /Users/parth/temp/github_events/2015/" |> to_charlist() |> :os.cmd() |> to_string() |> String.split("\n") |> Enum.reject(&String.starts_with?(&1, "total")) |> Enum.map(&String.split(&1, ~r/\s+/)) |> Enum.map(&Enum.at(&1, 4)) |> Enum.reject(&(is_nil &1)) |> Enum.map(&(String.to_integer &1)) |> Enum.sum() |> then(&(&1/:math.pow(10, 9))) |> Float.round(2) |> IO.inspect(label: "Size in GBs => ") 

P.S In practise this code might be shortened by using the standard library functions associated with file handling. But it was fun coming up with this!