Appendix H. Updating an R installation

As consumers, we take for granted that we can update a piece of software via a “Check for updates...” option. In chapter 1, I noted that the update.packages() function can be used to download and install the most recent version of a contributed package. Unfortunately, there’s no corresponding function for updating the R installation itself. If you want to update an R installation from version 4.1.0 to 5.1.1, you must get creative. (As I write this, the current version is actually 2.13.0, but I want this book to appear hip and current for years to come).

Downloading and installing the latest version of R from CRAN (http://cran.r-project.org/bin/) is relatively straightforward. The complicating factor is that customizations (including previously installed contributed packages) will not be included in the new installation. In my current set-up, I have 248 contributed packages installed. I really don’t want to have to write their names down and reinstall them by hand the next time I upgrade my R installation.

There has been much discussion on the web concerning the most elegant and efficient way to update an R installation. The method described below is neither elegant nor efficient, but I find that it works well on a variety of platforms (Windows, Mac, and Linux).