How to duplicate stdout/stderr?

[Samuel_Ainsworth]

I’m looking for a way to duplicate stdout/stderr. I’m aware of I/O and Network · The Julia Language which is great, but unfortunately it captures stdout instead of duplicating it.

In python I use:

logfile = tempfile.NamedTemporaryFile()
tee = subprocess.Popen(["tee", logfile.name], stdin=subprocess.PIPE)
# Cause tee's stdin to get a copy of our stdin/stdout (as well as that of any
# child processes we spawn).
os.dup2(tee.stdin.fileno(), sys.stdout.fileno())
os.dup2(tee.stdin.fileno(), sys.stderr.fileno())

and that worked wonders. Is there any way to accomplish this in Julia?

[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")