Jupyter notebook capture stdout and stderr like python capture magic?

[stevengj]

@jamblejoe

I do not want to redirect ALL output, just the output of some code running in specific cells in a jupyter notebook.

let old_stdout = stdout
    rd, = redirect_stdout()
    try
        println("This output is redirected.\n")
    finally
        redirect_stdout(old_stdout) # restore original stdout
    end
    output = String(readavailable(rd))
    println("captured the output: ", output)
end