title: Knitr: redirect chunk code output to terminal
body: <p>I want to monitor some pretty lengthy parallelized computations embedded in a knitr file.</p>
  
  <p>The computations rely on a package I have written, and the relevant function uses mclapply from the <em>multicore</em> package for parallelization. This function outputs progress bars to monitor the progress of the computations using a slightly modified implementation of <em>txtProgressBar</em> from the <em>utils</em> package. The progress bar is printed to the terminal and updated through a fifo connection every time an iteration of <em>mclapply</em> is complete. </p>
  
  <p>This works fine when sourcing from a file or calling directly the function, but I find no way to get this to work within knitr. I have tried the relevant chunk options, I can get messages and warnings redirected to the terminal, but not the progress bar. Can anyone help? </p>
  
  <p>Sorry for not providing a minimal working example but I don't see how I could make one in this setting. </p>