Passing this option hence turns off the
           usual output from both the system manager and the kernel.

       debug
           Turn on debugging output. This is equivalent to
           systemd.log_level=debug. Note that this option is also read by the
           kernel itself and enables kernel debug output. Passing this option
           hence turns on the debug output from both the system manager and the
           kernel.

       emergency, rd.emergency, -b
           Boot into emergency mode. This is equivalent to
           systemd.unit=emergency.target or rd.systemd.unit=emergency.target,
           respectively, and provided for compatibility reasons and to be
           easier to type.

       rescue, rd.rescue, single, s, S, 1
           Boot into rescue mode. This is equivalent to
           systemd.unit=rescue.target or rd.systemd.unit=rescue.target,
           respectively, and provided for compatibility reasons and to be
           easier to type.

       2, 3, 4, 5
           Boot into the specified legacy SysV runlevel. These are equivalent
           to systemd.unit=runlevel2.target, systemd.unit=runlevel3.target,
           systemd.unit=runlevel4.target, and systemd.unit=runlevel5.target,
           respectively, and provided for compatibility reasons and to be
           easier to type.

       locale.LANG=, locale.LANGUAGE=, locale.LC_CTYPE=, locale.LC_NUMERIC=,
       locale.LC_TIME=, locale.LC_COLLATE=, locale.LC_MONETARY=,
       locale.LC_MESSAGES=, locale.LC_PAPER=, locale.LC_NAME=,
       locale.LC_ADDRESS=, locale.LC_TELEPHONE=, locale.LC_MEASUREMENT=,
       locale.LC_IDENTIFICATION=
           Set the system locale to use. This overrides the settings in
           /etc/locale.conf. For more information, see locale.conf(5) and
           locale(7).

       For other kernel command line parameters understood by components of the
       core OS, please refer to kernel‐command‐line(7).

OPTIONS
       systemd is only very rarely invoked directly, since it is started early
       and is already running by the time users may interact with it. Normally,
       tools like systemctl(1) are used to give commands to the manager. Since
       systemd is usually not invoked directly, the options listed below are
       mostly useful for debugging and special purposes.

   Introspection and debugging options
       Those options are used for testing and introspection, and systemd may be
       invoked with them at any time:

       --dump-configuration-items
           Dump understood unit configuration items. This outputs a terse but
           complete list of configuration items understood in unit definition
           files.

       --dump-bus-properties
           Dump exposed bus properties. This outputs a terse but complete list
           of properties exposed on D-Bus.

       --test
           Determine the initial start-up transaction (i.e. the list of jobs
           enqueued at start-up), dump it and exit — without actually executing
           any of the determined jobs. This option is useful for debugging
           only. Note that during regular service manager start-up additional
           units not shown by this operation may be started, because hardware,
           socket, bus or other kinds of activation might add additional jobs
           as the transaction is executed. Use --system to request the initial
           transaction of the system service manager (this is also the implied
           default), combine with --user to request the initial transaction of
           the per-user service manager instead.

       --system, --user
           When used in conjunction with --test, selects whether to calculate
           the initial transaction for the system instance or for a per-user
           instance. These options have no effect when invoked without --test,
           as during regular (i.e. non---test) invocations the service manager
           will automatically detect whether