Question

I have a Macintosh and I am trying to automatically load packages, homemade functions, and use modified setting every time I start R. I believe this can be done with a file called Rprofile.site, and by creating the functions .First and .Last in that file.

One problem is, I have no idea what my R_HOME directory is, what it is used for, or if it even exists. I found two functions that I thought both gave me its location but I am getting different results.

Here’s the first

> Sys.getenv("R_home")
R_home 
    ""

And the second

> R.home()
[1] "/Library/Frameworks/R.framework/Resources"

As far as I can tell that second directory doesn’t even exist on my machine. I am currently running R from my applications directory.

Answer 1

Over the years I have come to rely on the help(Startup) documentation as the best place to read up on this. There are numerous per-user and per-site configuration file as is customary for rich applications. It may seem like overkill at first but it is a really good system. And once you grok Renviron versus Renviron.site and dito for Rprofile, you appreciate the consistent behaviour across platforms.