systems.

       --boot-loader-menu=timeout
           When used with the reboot command, indicate to the system's boot loader to show the boot loader menu on the following boot. Takes a time value as parameter — indicating the menu timeout. Pass zero in order to
           disable the menu timeout. Note that not all boot loaders support this functionality.

       --boot-loader-entry=ID
           When used with the reboot command, indicate to the system's boot loader to boot into a specific boot loader entry on the following boot. Takes a boot loader entry identifier as argument, or "help" in order to list
           available entries. Note that not all boot loaders support this functionality.

       --reboot-argument=
           This switch is used with reboot. The value is architecture and firmware specific. As an example, "recovery" might be used to trigger system recovery, and "fota" might be used to trigger a “firmware over the air”
           update.

       --plain
           When used with list-dependencies, list-units or list-machines, the output is printed as a list instead of a tree, and the bullet circles are omitted.

       --timestamp=
           Change the format of printed timestamps. The following values may be used:

           pretty (this is the default)
               "Day YYYY-MM-DD HH:MM:SS TZ"

           unix
               "@seconds-since-the-epoch"

           us, µs
               "Day YYYY-MM-DD HH:MM:SS.UUUUUU TZ"

           utc
               "Day YYYY-MM-DD HH:MM:SS UTC"

           us+utc, µs+utc
               "Day YYYY-MM-DD HH:MM:SS.UUUUUU UTC"

       --mkdir
           When used with bind, creates the destination file or directory before applying the bind mount. Note that even though the name of this option suggests that it is suitable only for directories, this option also
           creates the destination file node to mount over if the object to mount is not a directory, but a regular file, device node, socket or FIFO.

       --marked
           Only allowed with reload-or-restart. Enqueues restart jobs for all units that have the "needs-restart" mark, and reload jobs for units that have the "needs-reload" mark. When a unit marked for reload does not
           support reload, restart will be queued. Those properties can be set using set-property Markers=....

           Unless --no-block is used, systemctl will wait for the queued jobs to finish.

       --read-only
           When used with bind, creates a read-only bind mount.

       --drop-in=
           When used with edit, use the given drop-in file name instead of override.conf.

       -H, --host=
           Execute the operation remotely. Specify a hostname, or a username and hostname separated by "@", to connect to. The hostname may optionally be suffixed by a port ssh is listening on, separated by ":", and then a
           container name, separated by "/", which connects directly to a specific container on the specified host. This will use SSH to talk to the remote machine manager instance. Container names may be enumerated with
           machinectl -H HOST. Put IPv6 addresses in brackets.

       -M, --machine=
           Execute operation on a local container. Specify a container name to connect to, optionally prefixed by a user name to connect as and a separating "@" character. If the special string ".host" is used in place of
           the container name, a connection to the local system is made (which is useful to connect to a specific user's user bus: "--user --machine=lennart@.host"). If the "@" syntax is not used, the connection is made as
           root user. If the "@" syntax is used either the left hand side or the right hand side may be omitted (but not both) in which case the local user name and ".host" are implied.

       --no-pager
           Do not pipe output into a pager.

       --legend=BOOL
           Enable or disable printing of the legend, i.e. column headers and the footer with hints. The