     {snapshots, options} =
       case OptionParser.parse(args, strict: switches, aliases: aliases) do
         {opts, [], []} ->
-          {["-"], opts}
+          {locate_snapshots(), opts}
         {opts, snapshots, []} ->
           {snapshots, opts}
         {_, _, [{opt, val}|_]} ->

      |> normalize_options()

    case snapshots do
      [snapshot] -> pretty_print(snapshot)
      [first|rest] ->
        last = List.last(rest)
        compare(first, last, Map.get(options, :format, :ratio))
    end
  end

  defp normalize_options({snapshots, options}) do

  end

  defp pretty_print(path) do
    IO.puts "#{path}\n"
    path |> File.read! |> Snapshot.parse |> Snapshot.pretty_print
  end

  defp compare(path1, path2, format) do
    IO.puts "#{path1} vs\n#{path2}\n"

    snapshot1 = File.read!(path1) |> Snapshot.parse()
    snapshot2 = File.read!(path2) |> Snapshot.parse()
    {diffs, leftover} = Snapshot.compare(snapshot1, snapshot2, format)
