Easier way to feed stdin to external program and fetch stdout?

[simeonschaub]

You can use open on a command and pass your own IO object for open to use as stdout. sprint() do io then collects everything written into io as a string.

julia> sprint() do out_stream
           open(`cat`, "w", out_stream) do in_stream
               println(in_stream, "Hello world!")
           end
       end
"Hello world!\n"