title: -bash: R: command not found
body: <p>I often start an instance of R in my terminal just by entering "R".  Just not today.  I can open <code>R.app</code> using <code>open -a R</code> and open Rstudio using <code>open -a Rstudio</code>, and these work fine, but I'm failing at <code>R</code> and <code>R CMD BATCH ...</code> etc.  How can I start to diagnose this?</p>