How to Update Ruby Versions on Linux with rbenv

Update ruby-build as an rbenv plugin

cd ~/.rbenv/plugins/ruby-build

git pull

Find Available versions

rbenv install --list

Install version

rbenv install 2.1.5

Set the ruby version to use globally

rbenv global 2.1.5

Check ruby version

ruby -v

Note: You need to Reinstall bundler for each version of Ruby you use

Errors:

./libffi-3.2.1/.libs/libffi.a: could not read symbols: Bad value

Solution: Install libffi-dev

sudo apt-get install libffi-dev

Sources: makandracards digitalocean