$ rvm use [ruby-string] Setup current shell to use a specific ruby version. For a list of currently installed ruby string please run $ rvm list To create a gemset if it does not already exist: $ rvm --create 1.9.2@funky For creating a project .rvmrc file - From within the app's root_dir: $ rvm --rvmrc 1.9.2@funky Above commands can be also combined to do it all in one pass: $ rvm --rvmrc --create use 1.9.2@funky Using /home/user/.rvm/gems/ruby-1.9.2-p290 with gemset funky Do not forget to check the generated .rvmrc file - it contains many useful comments. Note you must still 'rvm rvmrc trust' the newly created .rvmrc If you attempt to use a ruby that is not installed and install-on-use is not enabled, rvm will tell you the command necessary to install the requested ruby. $ rvm use 1.9.3 ruby-1.9.3 is not installed. To install do: 'rvm install ruby-1.9.3' Also, an environment variable "rvm_recommended_ruby" will contain the command. Using tab completion will expedite executing it. $ $rvm_recommended_ruby To set a ruby as the user default, use the --default option. $ rvm use 1.9.3 --default To specify MRI patch level version use -l or --level option. Please see documentation for further information: https://rvm.io/rvm/basics Also, you can combine the new flags --ruby-version and --version-conf $ rvm --create --ruby-version use 1.9.2@funky Using /home/user/.rvm/gems/ruby-1.9.2-p290 with gemset funky $ rvm --create --versions-conf use 1.9.2@funky Using /home/user/.rvm/gems/ruby-1.9.2-p290 with gemset funky These files do not need to be trusted, however, if a .rvmrc file exists, it will override the use of .ruby-version or .versions.conf! Please see the documentation for further information: https://rvm.io/workflow/projects#ruby-versions