/usr/lib/ruby/2.0.0/rubygems/commands/ is in libruby2.0 2.0.0.484-1ubuntu2.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/2.0.0/rubygems/commands/build_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/cert_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/check_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/cleanup_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/contents_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/dependency_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/environment_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/fetch_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/generate_index_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/help_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/install_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/list_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/lock_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/mirror_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/outdated_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/owner_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/pristine_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/push_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/query_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/rdoc_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/search_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/server_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/setup_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/sources_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/specification_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/stale_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/uninstall_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/unpack_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/update_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/which_command.rb
/usr/lib/ruby/2.0.0/rubygems/commands/yank_command.rb