title: Can homebrew R and "standard" R for MacOS from CRAN coexist?
body: <p>I am running <code>R 3.6.1</code> on a Mac Mini running Sierra and a MacBook Pro running El Capitan. I normally get all the <code>R</code> packages that I need from CRAN or <code>github</code> and use them without issues, but I am trying to install and use an <code>R</code> package (<code>NicheMapR</code>) that requires a <code>fortran</code> compiler and this is giving me issues. Even after installing <code>gfortran</code>, the <code>R</code> package still does not work (the <code>fortran</code> code seems to be compiled but the package installation fails). The package developer suggested that installing <code>R</code> via <code>homebrew</code> might solve the problem. On the contrary, my hunch is that it would lead to a world of pain, to quote Walter from the Big Lebowski. My questions are:</p>
  
  <ol>
  <li>What is the advantage of a homebrew version of R for MacOSX over the "regular" version installed from CRAN? </li>
  <li><strong>Can the two versions coexist?</strong> </li>
  <li>Is the homebrew version going to affect the regular one?</li>
  <li><p>Finally: is homebrew going to help or will it simply open a whole
  new can of worms?</p>
  
  <p>Many thanks in advance.</p></li>
  </ol>