How to resolve Github build R 3.5 cask error?

Question

I recently installed git and incorporated it with R studio so that I can use github's version control system. I am new to git and github, so I am out of my depth when it comes to figuring out how to resolve errors. The issue I have is that my "push" actions keep failing. Attached is a screenshot of the code that runs in github, and the associated error. Each action fails when trying to set up R 3.5 with the error, "Error: Unknown command: cask." I looked at the HomeBrew page on github but haven't seen any issues similar to mine. I see some code lines I could run to try to update cask but I don't know where I am supposed to run them. Homebrew gives the following line to run to update cask: "brew bump-cask-pr --version <new_version> <outdated_cask>". But this doesn't run in r or gitbash so I'm not sure where I am supposed to be inputting it. Any insight is much appreciated!

Screenshot of error

Answer 1

If you get Error: Unknown command: cask, it's because cask is no longer a separate command within Homebrew.

Just run (in your Terminal):

brew install rstudio

or

brew install --cask rstudio

This being said, I don't understand your precise issue. I don't think you need to install gfortran directly (it comes as a dependency with r), and more importantly, gfortran is not a cask...

If you want to use R and need some basic tools, just install R, RStudio and Git (brew install r rstudio git), and you should be fine.

Don't use brew bump-cask-pr. That's for maintenance of cask formulas (to signal Homebrew there is a new version of an app to update their database). Not necessary for a beggining user.