How to duplicate stdout/stderr?

[Tamas_Papp]

Write to file and stdout

This needs a lot more work to define a proper IO interface, but struct Tee{TIO <: Tuple} <: IO streams::TIO end Tee(streams...) = Tee(streams) function _do_tee(tee, f, xs...) for io in tee.streams f(io, xs...) end end Base.write(tee::Tee, x) = _do_tee(tee, write, x) Base.write(tee::Tee, x::Union{SubString{String},String}) = _do_tee(tee, write, x) print(Tee(stdout, stderr), "will appear twice")