Ruby
Ruby is the language of TaskJuggler, Vagrant and MediaWiki-Vagrant.
There is a tool called ruby-switch that can allow you to check, list, and set the Ruby interpreter system-wide. This includes ruby, gem, irb, erb, testrb, rdoc, ri
ruby-switch --check Currently using: ruby2.0 ------------------------ ruby -> /usr/bin/ruby2.0 gem -> /usr/bin/gem2.0