    # File lib/chef/knife/role_bulk_delete.rb, line 32
          def run
            if @name_args.length < 1
              ui.error("You must supply a regular expression to match the results against")
              exit 1
            end

            all_roles = Chef::Role.list(true)

            matcher = /#{@name_args[0]}/
            roles_to_delete = {}
            all_roles.each do |name, role|
              next unless name =~ matcher
              roles_to_delete[role.name] = role
            end

            if roles_to_delete.empty?
              ui.info "No roles match the expression /#{@name_args[0]}/"
              exit 0
            end

            ui.msg("The following roles will be deleted:")
            ui.msg("")
            ui.msg(ui.list(roles_to_delete.keys.sort, :columns_down))
            ui.msg("")
            ui.confirm("Are you sure you want to delete these roles")

            roles_to_delete.sort.each do |name, role|
              role.destroy
              ui.msg("Deleted role #{name}")
            end
          end