title: How to use coproc on Mac OS X 11?
body: <p>I'm trying to cross io between two processes and coproc does not seem to be installed in OS X 10.11.x.</p>
  
  <p>I get:
  bash: coproc: command not found</p>
  
  <p>My bash version is: GNU bash, version 4.3.42(1)-release (x86_64-apple-darwin15.3.0)</p>
  
  <p>How can I install coproc?</p>