def valid_command_names_from(*args)
      arg_string = args.delete_if { |value| value =~ /^-/ }.join ' '
      commands.keys.find_all { |name| name if /^#{name}\b/.match arg_string }
    end
def valid_command_names_from(*args)
      arg_string = args.delete_if { |value| value =~ /^-/ }.join ' '
      commands.keys.find_all { |name| name if /^#{name}\b/.match arg_string }
    end
Returns array of valid command names found within _args_.