R/ RStudio - install devtools fails?

The error messages may be a bit confusing, because RStudio is asking you to install libcurl and openssl libraries for your Linux OS; for those you actually need Ubuntu packages instead of R packages.

Open a command line terminal, and type

sudo apt-get install libcurl4-openssl-dev libssl-dev 

Once the installation of your Ubuntu packages is completed, try again and you'll be able to install the devtools R package

We can use

sudo apt-get install libssl-dev