Rbenv update Rubygems

update.sh

#!/usr/bin/env sh

# Multiple vulnerabilities have been disclosed in RubyGems:
# https://www.ruby-lang.org/en/news/2018/02/17/multiple-vulnerabilities-in-rubygems/
#
# If you're an Rbenv user, here's any easy one-liner to upgrade to a 
# safe version of Rubygems (2.7.6 or later) for each installed Ruby version:

for i in $( rbenv versions --bare ); do RBENV_VERSION=$i gem update --system && echo "\n$(ruby -v) using rubygems $(gem --version)\n"; done