How to upgrade (not install new) R-studio on Linux Mint 17.2 Rafaela?
These commands are correct?
sudo gedit /etc/apt/sources.list
sudo apt-get updat
On Linux Mint 17.3, I personally just use the link from the RStudio website whenever I want to update:
https://www.rstudio.com/products/rstudio/download/
I use the .deb link for Ubuntu/64 bit (Mint is built over Ubuntu).
The commands you are trying to run suggest you're trying to upgrade R, not RStudio (an IDE for programming in R)...
For upgrading R itself, I follow my own answer here, which is basically to grab a .deb file for R from the RStudio website here.