At the bottom of the R for macOS Developer’s Page there’s mention of an “other binary” called “RSwitch” that is “a small GUI that allows you to switch between R versions quickly (if you have multiple versions of R framework installed).” Said switching requires you to use the “tar.gz” versions of R from the R for macOS Developer’s Page since the official CRAN binary installers clean up after themselves quite nicely to prevent potentially wacky behavior.

All the RSwitch GUI did was change the Current alias target in /Library/Frameworks/R.framework/Versions to the appropriate version. You can do that from the command line but the switcher GUI was created so that means some folks prefer click-switching and I have found myself using the GUI on occasion (before it stopped working on macOS Vista^wCatalina).

Since I:

• work on Catalina most of the day
• play with oldrel and devel versions of R
• needed to brush up on Swift 5 coding
• wanted RSwitch as a menubar app vs one with a dialog that I could easily lose across 15 desktops
• decided to see if it was possible to make it work sandboxed (TLDR: it isn’t)
• really wanted a different icon for the binary
• couldn’t sleep last night

there was sufficient justification to create a 64-bit version of this app.

You can clone the project from any of the following social coding sites:

• Gitea (self-hosted)
• SourceHut
• GitLab
• BitBucket
• GitHub

and, you can either compile it yourself — which is recommended since it’s 2019 and the days of even remotely trusting binaries off the internet are long gone — or build it. It should work on 10.14+ since I set that as the target, but file an issue where you like if you have, well, issues with the code or binary.

Once you do have it working, there will be a dial-switch menu in the menubar and a menu that should look something like:

The item with the checkbox is the Current alias.

FIN

Kick the tyres, file issues & PRs as you’re wont to do and prepare for the forthcoming clickpocalypse as Apple nears their GA release of Catalina.