The question is based on this answer.
How can you set the -R in your LESS environment variable?
Taken from the manpage:
Options are also taken from the environment variable "LESS". For example, to avoid typing "less -options ..." each time less is invoked, you might tell csh: setenv LESS "-options" or if you use sh: LESS="-options"; export LESS
If you are using Bash which is the default on a variety of distributions we can therefore do:
If you want to make this permanent across shell/login sessions then you need to add the command(s) above to the appropriate file, with Bash as the example again you'd open up $HOME/.bashrc with a text editor and drop in the export command. This means each time Bash invokes it will run the export command, setting your Less preferences.
Hope that helps :-)