software engineering Ruby error: find_spec_for_exe': can't find gem bundler (>= 0.a) I decided I was going to try to develop on my Ubuntu machine today and I ran into the following error: .rbenv/versions/2.5.0/lib/ruby/2.5.0/rubygems.rb:289:in `find_spec_for_exe': can't find gem bundler (>= 0.