--options accepted are

--help Print usage and exit

--version
       Print version and exit

--verbose
       Print information on progress

--default-packages=list
       Where 'list' is a comma-separated set of package names, or 'NULL'

and also options to R (in addition to --slave --no-restore), such as

--save Do save workspace at the end of the session

--no-environ
       Don't read the site and user environment files

--no-site-file
       Don't read the site-wide Rprofile

--no-init-file
       Don't read the user R profile

--restore
       Do restore previously saved objects at startup

--vanilla
       Combine --no-save, --no-restore, --no-site-file --no-init-file and --no-environ