https://stat.ethz.ch/R-manual/R-devel/library/base/html/Startup.html



R_PROFILE_USER

R_ENVIRON - name of the site file
R_ENVIRON_USER - name of the user


R_HOME - set to the user private directory

 --no-init-file was given, R searches for a user profile

	
You can use the .Rprofile.site file to run R commands for all users when their R session starts. 
