Collecting all output from shell commands

General Usage
6

With this suggestion

function execute(cmd::Cmd)
  out = Pipe()
  err = Pipe()

  process = run(pipeline(ignorestatus(cmd), stdout=out, stderr=err))
  close(out.in)
  close(err.in)
  stdout = @async String(read(out))
  stderr = @async String(read(err))
  (
    stdout = String(read(out)), 
    stderr = String(read(err)),  
    code = process.exitcode
  )
end

julia> a, = execute(`cmd /c dir C:`); println(a)
julia> a, = execute(`cmd /c dir C:`); println(a)
julia> a, = execute(`cmd /c dir C:`); println(a)
(repeatdly enter the above by executing each line and then hitting the up arrow and executing again)

What you will see is that sometimes it prints the information , but also occasionally prints nothing. Is there a way to avoid this situation.