Create the ~/.gemrc file with the following content:
gem: --no-rdoc --no-ri --user-install
Add these lines to your .bash_profile:
for entry in ~/.gem/ruby/*; do PATH=$entry/bin:$PATH; done
export PATH
export BUNDLE_PATH=~/.gem/bundle
Now you can install gems without needing your root password:
gem install rspec
which rspec
# /home/me/.gem/ruby/2.7.0/bin/rspec
Bundler with a Gemfile:
source 'https://rubygems.org'
gem 'rspec'
You can prefix your commands with bundle exec:
bundle install
bundle exec which rspec
# /home/me/.gem/bundle/ruby/2.7.0/bin/rspec
Don’t forget to clean up your old ruby gems directories:
ls -la /home/me/.gem/ruby
ls -la /home/me/.gem/bundle/ruby
Keep only the version matching your latest ruby!