machinectl(category30-tips-tricks-fragen.html) - phpMan

MACHINECTL(1)                     machinectl                     MACHINECTL(1)
NAME
       machinectl - Control the systemd machine manager
SYNOPSIS
       machinectl [OPTIONS...] {COMMAND} [NAME...]
DESCRIPTION
       machinectl may be used to introspect and control the state of the
       systemd(1) virtual machine and container registration manager systemd-
       machined.service(8).
       machinectl may be used to execute operations on machines and images.
       Machines in this sense are considered running instances of:
       o   Virtual Machines (VMs) that virtualize hardware to run full
           operating system (OS) instances (including their kernels) in a
           virtualized environment on top of the host OS.
       o   Containers that share the hardware and OS kernel with the host OS,
           in order to run OS userspace instances on top the host OS.
       o   The host system itself.
       Machines are identified by names that follow the same rules as UNIX and
       DNS host names. For details, see below.
       Machines are instantiated from disk or file system images that
       frequently -- but not necessarily -- carry the same name as machines
       running from them. Images in this sense may be:
       o   Directory trees containing an OS, including the top-level
           directories /usr, /etc, and so on.
       o   btrfs subvolumes containing OS trees, similar to normal directory
           trees.
       o   Binary "raw" disk images containing MBR or GPT partition tables and
           Linux file system partitions.
       o   The file system tree of the host OS itself.
OPTIONS
       The following options are understood:
       -p, --property=
           When showing machine or image properties, limit the output to
           certain properties as specified by the argument. If not specified,
           all set properties are shown. The argument should be a property
           name, such as "Name". If specified more than once, all properties
           with the specified names are shown.
       -a, --all
           When showing machine or image properties, show all properties
           regardless of whether they are set or not.
           When listing VM or container images, do not suppress images
           beginning in a dot character (".").
           When cleaning VM or container images, remove all images, not just
           hidden ones.
       --value
           When printing properties with show, only print the value, and skip
           the property name and "=".
       -l, --full
           Do not ellipsize process tree entries.
       --kill-who=
           When used with kill, choose which processes to kill. Must be one of
           leader, or all to select whether to kill only the leader process of
           the machine or all processes of the machine. If omitted, defaults
           to all.
       -s, --signal=
           When used with kill, choose which signal to send to selected
           processes. Must be one of the well-known signal specifiers, such as
           SIGTERM, SIGINT or SIGSTOP. If omitted, defaults to SIGTERM.
       --uid=
           When used with the shell command, chooses the user ID to open the
           interactive shell session as. If the argument to the shell command
           also specifies a user name, this option is ignored. If the name is
           not specified in either way, "root" will be used by default. Note
           that this switch is not supported for the login command (see
           below).
       -E NAME=VALUE, --setenv=NAME=VALUE
           When used with the shell command, sets an environment variable to
           pass to the executed shell. Takes an environment variable name and
           value, separated by "=". This switch may be used multiple times to
           set multiple environment variables. Note that this switch is not
           supported for the login command (see below).
       --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.
       --read-only
           When used with bind, creates a read-only bind mount.
           When used with clone, import-raw or import-tar a read-only
           container or VM image is created.
       -n, --lines=
           When used with status, controls the number of journal lines to
           show, counting from the most recent ones. Takes a positive integer
           argument. Defaults to 10.
       -o, --output=
           When used with status, controls the formatting of the journal
           entries that are shown. For the available choices, see
           journalctl(1). Defaults to "short".
       --verify=
           When downloading a container or VM image, specify whether the image
           shall be verified before it is made available. Takes one of "no",
           "checksum" and "signature". If "no", no verification is done. If
           "checksum" is specified, the download is checked for integrity
           after the transfer is complete, but no signatures are verified. If
           "signature" is specified, the checksum is verified and the image's
           signature is checked against a local keyring of trustable vendors.
           It is strongly recommended to set this option to "signature" if the
           server and protocol support this. Defaults to "signature".
       --force
           When downloading a container or VM image, and a local copy by the
           specified local machine name already exists, delete it first and
           replace it by the newly downloaded image.
       --format=
           When used with the export-tar or export-raw commands, specifies the
           compression format to use for the resulting file. Takes one of
           "uncompressed", "xz", "gzip", "bzip2". By default, the format is
           determined automatically from the image file name passed.
       --max-addresses=
           When used with the list-machines command, limits the number of ip
           addresses output for every machine. Defaults to 1. All addresses
           can be requested with "all" as argument to --max-addresses . If the
           argument to --max-addresses is less than the actual number of
           addresses, "..."follows the last address. If multiple addresses are
           to be written for a given machine, every address except the first
           one is on a new line and is followed by "," if another address will
           be output afterwards.
       -q, --quiet
           Suppresses additional informational output while running.
       -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 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.
       -M, --machine=
           Connect to systemd-machined.service(8) running in a local
           container, to perform the specified operation within the container.
       --no-pager
           Do not pipe output into a pager.
       --no-legend
           Do not print the legend, i.e. column headers and the footer with
           hints.
       --no-ask-password
           Do not query the user for authentication for privileged operations.
       -h, --help
           Print a short help text and exit.
       --version
           Print a short version string and exit.
COMMANDS
       The following commands are understood:
   Machine Commands
       list
           List currently running (online) virtual machines and containers. To
           enumerate machine images that can be started, use list-images (see
           below). Note that this command hides the special ".host" machine by
           default. Use the --all switch to show it.
       status NAME...
           Show runtime status information about one or more virtual machines
           and containers, followed by the most recent log data from the
           journal. This function is intended to generate human-readable
           output. If you are looking for computer-parsable output, use show
           instead. Note that the log data shown is reported by the virtual
           machine or container manager, and frequently contains console
           output of the machine, but not necessarily journal contents of the
           machine itself.
       show [NAME...]
           Show properties of one or more registered virtual machines or
           containers or the manager itself. If no argument is specified,
           properties of the manager will be shown. If a NAME is specified,
           properties of this virtual machine or container are shown. By
           default, empty properties are suppressed. Use --all to show those
           too. To select specific properties to show, use --property=. This
           command is intended to be used whenever computer-parsable output is
           required, and does not print the control group tree or journal
           entries. Use status if you are looking for formatted human-readable
           output.
       start NAME...
           Start a container as a system service, using systemd-nspawn(1).
           This starts systemd-nspawn@.service, instantiated for the specified
           machine name, similar to the effect of systemctl start on the
           service name.  systemd-nspawn looks for a container image by the
           specified name in /var/lib/machines/ (and other search paths, see
           below) and runs it. Use list-images (see below) for listing
           available container images to start.
           Note that systemd-machined.service(8) also interfaces with a
           variety of other container and VM managers, systemd-nspawn is just
           one implementation of it. Most of the commands available in
           machinectl may be used on containers or VMs controlled by other
           managers, not just systemd-nspawn. Starting VMs and container
           images on those managers requires manager-specific tools.
           To interactively start a container on the command line with full
           access to the container's console, please invoke systemd-nspawn
           directly. To stop a running container use machinectl poweroff.
       login [NAME]
           Open an interactive terminal login session in a container or on the
           local host. If an argument is supplied, it refers to the container
           machine to connect to. If none is specified, or the container name
           is specified as the empty string, or the special machine name
           ".host" (see below) is specified, the connection is made to the
           local host instead. This will create a TTY connection to a specific
           container or the local host and asks for the execution of a getty
           on it. Note that this is only supported for containers running
           systemd(1) as init system.
           This command will open a full login prompt on the container or the
           local host, which then asks for username and password. Use shell
           (see below) or systemd-run(1) with the --machine= switch to
           directly invoke a single command, either interactively or in the
           background.
       shell [[NAME@]NAME [PATH [ARGUMENTS...]]]
           Open an interactive shell session in a container or on the local
           host. The first argument refers to the container machine to connect
           to. If none is specified, or the machine name is specified as the
           empty string, or the special machine name ".host" (see below) is
           specified, the connection is made to the local host instead. This
           works similar to login but immediately invokes a user process. This
           command runs the specified executable with the specified arguments,
           or the default shell for the user if none is specified, or /bin/sh
           if no default shell is found. By default, --uid=, or by prefixing
           the machine name with a username and an "@" character, a different
           user may be selected. Use --setenv= to set environment variables
           for the executed process.
           Note that machinectl shell does not propagate the exit code/status
           of the invoked shell process. Use systemd-run instead if that
           information is required (see below).
           When using the shell command without arguments, (thus invoking the
           executed shell or command on the local host), it is in many ways
           similar to a su(1) session, but, unlike su, completely isolates the
           new session from the originating session, so that it shares no
           process or session properties, and is in a clean and well-defined
           state. It will be tracked in a new utmp, login, audit, security and
           keyring session, and will not inherit any environment variables or
           resource limits, among other properties.
           Note that systemd-run(1) with its --machine= switch may be used in
           place of the machinectl shell command, and allows non-interactive
           operation, more detailed and low-level configuration of the invoked
           unit, as well as access to runtime and exit code/status information
           of the invoked shell process. In particular, use systemd-run's
           --wait switch to propagate exit status information of the invoked
           process. Use systemd-run's --pty switch for acquiring an
           interactive shell, similar to machinectl shell. In general,
           systemd-run is preferable for scripting purposes. However, note
           that systemd-run might require higher privileges than machinectl
           shell.
       enable NAME..., disable NAME...
           Enable or disable a container as a system service to start at
           system boot, using systemd-nspawn(1). This enables or disables
           systemd-nspawn@.service, instantiated for the specified machine
           name, similar to the effect of systemctl enable or systemctl
           disable on the service name.
       poweroff NAME...
           Power off one or more containers. This will trigger a reboot by
           sending SIGRTMIN+4 to the container's init process, which causes
           systemd-compatible init systems to shut down cleanly. Use stop as
           alias for poweroff. This operation does not work on containers that
           do not run a systemd(1)-compatible init system, such as sysvinit.
           Use terminate (see below) to immediately terminate a container or
           VM, without cleanly shutting it down.
       reboot NAME...
           Reboot one or more containers. This will trigger a reboot by
           sending SIGINT to the container's init process, which is roughly
           equivalent to pressing Ctrl+Alt+Del on a non-containerized system,
           and is compatible with containers running any system manager.
       terminate NAME...
           Immediately terminates a virtual machine or container, without
           cleanly shutting it down. This kills all processes of the virtual
           machine or container and deallocates all resources attached to that
           instance. Use poweroff to issue a clean shutdown request.
       kill NAME...
           Send a signal to one or more processes of the virtual machine or
           container. This means processes as seen by the host, not the
           processes inside the virtual machine or container. Use --kill-who=
           to select which process to kill. Use --signal= to select the signal
           to send.
       bind NAME PATH [PATH]
           Bind mounts a file or directory from the host into the specified
           container. The first path argument is the source file or directory
           on the host, the second path argument is the destination file or
           directory in the container. When the latter is omitted, the
           destination path in the container is the same as the source path on
           the host. When combined with the --read-only switch, a ready-only
           bind mount is created. When combined with the --mkdir switch, the
           destination path is first created before the mount is applied. Note
           that this option is currently only supported for systemd-nspawn(1)
           containers, and only if user namespacing (--private-users) is not
           used. This command supports bind mounting directories, regular
           files, device nodes, AF_UNIX socket nodes, as well as FIFOs.
       copy-to NAME PATH [PATH]
           Copies files or directories from the host system into a running
           container. Takes a container name, followed by the source path on
           the host and the destination path in the container. If the
           destination path is omitted, the same as the source path is used.
           If host and container share the same user and group namespace, file
           ownership by numeric user ID and group ID is preserved for the
           copy, otherwise all files and directories in the copy will be owned
           by the root user and group (UID/GID 0).
       copy-from NAME PATH [PATH]
           Copies files or directories from a container into the host system.
           Takes a container name, followed by the source path in the
           container the destination path on the host. If the destination path
           is omitted, the same as the source path is used.
           If host and container share the same user and group namespace, file
           ownership by numeric user ID and group ID is preserved for the
           copy, otherwise all files and directories in the copy will be owned
           by the root user and group (UID/GID 0).
   Image Commands
       list-images
           Show a list of locally installed container and VM images. This
           enumerates all raw disk images and container directories and
           subvolumes in /var/lib/machines/ (and other search paths, see
           below). Use start (see above) to run a container off one of the
           listed images. Note that, by default, containers whose name begins
           with a dot (".") are not shown. To show these too, specify --all.
           Note that a special image ".host" always implicitly exists and
           refers to the image the host itself is booted from.
       image-status [NAME...]
           Show terse status information about one or more container or VM
           images. This function is intended to generate human-readable
           output. Use show-image (see below) to generate computer-parsable
           output instead.
       show-image [NAME...]
           Show properties of one or more registered virtual machine or
           container images, or the manager itself. If no argument is
           specified, properties of the manager will be shown. If a NAME is
           specified, properties of this virtual machine or container image
           are shown. By default, empty properties are suppressed. Use --all
           to show those too. To select specific properties to show, use
           --property=. This command is intended to be used whenever
           computer-parsable output is required. Use image-status if you are
           looking for formatted human-readable output.
       clone NAME NAME
           Clones a container or VM image. The arguments specify the name of
           the image to clone and the name of the newly cloned image. Note
           that plain directory container images are cloned into btrfs
           subvolume images with this command, if the underlying file system
           supports this. Note that cloning a container or VM image is
           optimized for file systems that support copy-on-write, and might
           not be efficient on others, due to file system limitations.
           Note that this command leaves host name, machine ID and all other
           settings that could identify the instance unmodified. The original
           image and the cloned copy will hence share these credentials, and
           it might be necessary to manually change them in the copy.
           If combined with the --read-only switch a read-only cloned image is
           created.
       rename NAME NAME
           Renames a container or VM image. The arguments specify the name of
           the image to rename and the new name of the image.
       read-only NAME [BOOL]
           Marks or (unmarks) a container or VM image read-only. Takes a VM or
           container image name, followed by a boolean as arguments. If the
           boolean is omitted, positive is implied, i.e. the image is marked
           read-only.
       remove NAME...
           Removes one or more container or VM images. The special image
           ".host", which refers to the host's own directory tree, may not be
           removed.
       set-limit [NAME] BYTES
           Sets the maximum size in bytes that a specific container or VM
           image, or all images, may grow up to on disk (disk quota). Takes
           either one or two parameters. The first, optional parameter refers
           to a container or VM image name. If specified, the size limit of
           the specified image is changed. If omitted, the overall size limit
           of the sum of all images stored locally is changed. The final
           argument specifies the size limit in bytes, possibly suffixed by
           the usual K, M, G, T units. If the size limit shall be disabled,
           specify "-" as size.
           Note that per-container size limits are only supported on btrfs
           file systems. Also note that, if set-limit is invoked without an
           image parameter, and /var/lib/machines is empty, and the directory
           is not located on btrfs, a btrfs loopback file is implicitly
           created as /var/lib/machines.raw with the given size, and mounted
           to /var/lib/machines. The size of the loopback may later be
           readjusted with set-limit, as well. If such a loopback-mounted
           /var/lib/machines directory is used, set-limit without an image
           name alters both the quota setting within the file system as well
           as the loopback file and file system size itself.
       clean
           Remove hidden VM or container images (or all). This command removes
           all hidden machine images from /var/lib/machines, i.e. those whose
           name begins with a dot. Use machinectl list-images --all to see a
           list of all machine images, including the hidden ones.
           When combined with the --all switch removes all images, not just
           hidden ones. This command effectively empties /var/lib/machines.
           Note that commands such as machinectl pull-tar or machinectl
           pull-raw usually create hidden, read-only, unmodified machine
           images from the downloaded image first, before cloning a writable
           working copy of it, in order to avoid duplicate downloads in case
           of images that are reused multiple times. Use machinectl clean to
           remove old, hidden images created this way.
   Image Transfer Commands
       pull-tar URL [NAME]
           Downloads a .tar container image from the specified URL, and makes
           it available under the specified local machine name. The URL must
           be of type "http://" or "https://", and must refer to a .tar,
           .tar.gz, .tar.xz or .tar.bz2 archive file. If the local machine
           name is omitted, it is automatically derived from the last
           component of the URL, with its suffix removed.
           The image is verified before it is made available, unless
           --verify=no is specified. Verification is done either via an inline
           signed file with the name of the image and the suffix .sha256 or
           via separate SHA256SUMS and SHA256SUMS.gpg files. The signature
           files need to be made available on the same web server, under the
           same URL as the .tar file. With --verify=checksum, only the SHA256
           checksum for the file is verified, based on the .sha256 suffixed
           file or theSHA256SUMS file. With --verify=signature, the sha
           checksum file is first verified with the inline signature in the
           .sha256 file or the detached GPG signature file SHA256SUMS.gpg. The
           public key for this verification step needs to be available in
           /usr/lib/systemd/import-pubring.gpg or
           /etc/systemd/import-pubring.gpg.
           The container image will be downloaded and stored in a read-only
           subvolume in /var/lib/machines/ that is named after the specified
           URL and its HTTP etag. A writable snapshot is then taken from this
           subvolume, and named after the specified local name. This behavior
           ensures that creating multiple container instances of the same URL
           is efficient, as multiple downloads are not necessary. In order to
           create only the read-only image, and avoid creating its writable
           snapshot, specify "-" as local machine name.
           Note that the read-only subvolume is prefixed with .tar-, and is
           thus not shown by list-images, unless --all is passed.
           Note that pressing C-c during execution of this command will not
           abort the download. Use cancel-transfer, described below.
       pull-raw URL [NAME]
           Downloads a .raw container or VM disk image from the specified URL,
           and makes it available under the specified local machine name. The
           URL must be of type "http://" or "https://". The container image
           must either be a .qcow2 or raw disk image, optionally compressed as
           .gz, .xz, or .bz2. If the local machine name is omitted, it is
           automatically derived from the last component of the URL, with its
           suffix removed.
           Image verification is identical for raw and tar images (see above).
           If the downloaded image is in .qcow2 format it is converted into a
           raw image file before it is made available.
           Downloaded images of this type will be placed as read-only .raw
           file in /var/lib/machines/. A local, writable (reflinked) copy is
           then made under the specified local machine name. To omit creation
           of the local, writable copy pass "-" as local machine name.
           Similar to the behavior of pull-tar, the read-only image is
           prefixed with .raw-, and thus not shown by list-images, unless
           --all is passed.
           Note that pressing C-c during execution of this command will not
           abort the download. Use cancel-transfer, described below.
       import-tar FILE [NAME], import-raw FILE [NAME]
           Imports a TAR or RAW container or VM image, and places it under the
           specified name in /var/lib/machines/. When import-tar is used, the
           file specified as the first argument should be a tar archive,
           possibly compressed with xz, gzip or bzip2. It will then be
           unpacked into its own subvolume in /var/lib/machines. When
           import-raw is used, the file should be a qcow2 or raw disk image,
           possibly compressed with xz, gzip or bzip2. If the second argument
           (the resulting image name) is not specified, it is automatically
           derived from the file name. If the filename is passed as "-", the
           image is read from standard input, in which case the second
           argument is mandatory.
           Both pull-tar and pull-raw will resize /var/lib/machines.raw and
           the filesystem therein as necessary. Optionally, the --read-only
           switch may be used to create a read-only container or VM image. No
           cryptographic validation is done when importing the images.
           Much like image downloads, ongoing imports may be listed with
           list-transfers and aborted with cancel-transfer.
       export-tar NAME [FILE], export-raw NAME [FILE]
           Exports a TAR or RAW container or VM image and stores it in the
           specified file. The first parameter should be a VM or container
           image name. The second parameter should be a file path the TAR or
           RAW image is written to. If the path ends in ".gz", the file is
           compressed with gzip, if it ends in ".xz", with xz, and if it ends
           in ".bz2", with bzip2. If the path ends in neither, the file is
           left uncompressed. If the second argument is missing, the image is
           written to standard output. The compression may also be explicitly
           selected with the --format= switch. This is in particular useful if
           the second parameter is left unspecified.
           Much like image downloads and imports, ongoing exports may be
           listed with list-transfers and aborted with cancel-transfer.
           Note that, currently, only directory and subvolume images may be
           exported as TAR images, and only raw disk images as RAW images.
       list-transfers
           Shows a list of container or VM image downloads, imports and
           exports that are currently in progress.
       cancel-transfer ID...
           Aborts a download, import or export of the container or VM image
           with the specified ID. To list ongoing transfers and their IDs, use
           list-transfers.
MACHINE AND IMAGE NAMES
       The machinectl tool operates on machines and images whose names must be
       chosen following strict rules. Machine names must be suitable for use
       as host names following a conservative subset of DNS and UNIX/Linux
       semantics. Specifically, they must consist of one or more non-empty
       label strings, separated by dots. No leading or trailing dots are
       allowed. No sequences of multiple dots are allowed. The label strings
       may only consist of alphanumeric characters as well as the dash and
       underscore. The maximum length of a machine name is 64 characters.
       A special machine with the name ".host" refers to the running host
       system itself. This is useful for execution operations or inspecting
       the host system as well. Note that machinectl list will not show this
       special machine unless the --all switch is specified.
       Requirements on image names are less strict, however, they must be
       valid UTF-8, must be suitable as file names (hence not be the single or
       double dot, and not include a slash), and may not contain control
       characters. Since many operations search for an image by the name of a
       requested machine, it is recommended to name images in the same strict
       fashion as machines.
       A special image with the name ".host" refers to the image of the
       running host system. It hence conceptually maps to the special ".host"
       machine name described above. Note that machinectl list-images will not
       show this special image either, unless --all is specified.
FILES AND DIRECTORIES
       Machine images are preferably stored in /var/lib/machines/, but are
       also searched for in /usr/local/lib/machines/ and /usr/lib/machines/.
       For compatibility reasons, the directory /var/lib/container/ is
       searched, too. Note that images stored below /usr are always considered
       read-only. It is possible to symlink machines images from other
       directories into /var/lib/machines/ to make them available for control
       with machinectl.
       Note that some image operations are only supported, efficient or atomic
       on btrfs file systems. Due to this, if the pull-tar, pull-raw,
       import-tar, import-raw and set-limit commands notice that
       /var/lib/machines is empty and not located on btrfs, they will
       implicitly set up a loopback file /var/lib/machines.raw containing a
       btrfs file system that is mounted to /var/lib/machines. The size of
       this loopback file may be controlled dynamically with set-limit.
       Disk images are understood by systemd-nspawn(1) and machinectl in three
       formats:
       o   A simple directory tree, containing the files and directories of
           the container to boot.
       o   Subvolumes (on btrfs file systems), which are similar to the simple
           directories, described above. However, they have additional
           benefits, such as efficient cloning and quota reporting.
       o   "Raw" disk images, i.e. binary images of disks with a GPT or MBR
           partition table. Images of this type are regular files with the
           suffix ".raw".
       See systemd-nspawn(1) for more information on image formats, in
       particular its --directory= and --image= options.
EXAMPLES
       Example 1. Download an Ubuntu image and open a shell in it
           # machinectl pull-tar https://cloud-images.ubuntu.com/trusty/current/trusty-server-cloudimg-amd64-root.tar.gz
           # systemd-nspawn -M trusty-server-cloudimg-amd64-root
       This downloads and verifies the specified .tar image, and then uses
       systemd-nspawn(1) to open a shell in it.
       Example 2. Download a Fedora image, set a root password in it, start it
       as service
           # machinectl pull-raw --verify=no https://dl.fedoraproject.org/pub/fedora/linux/releases/27/CloudImages/x86_64/images/Fedora-Cloud-Base-27-1.6.x86_64.raw.xz
           # systemd-nspawn -M Fedora-Cloud-Base-27-1.6.x86_64
           # passwd
           # exit
           # machinectl start Fedora-Cloud-Base-27-1.6.x86_64
           # machinectl login Fedora-Cloud-Base-27-1.6.x86_64
       This downloads the specified .raw image with verification disabled.
       Then, a shell is opened in it and a root password is set. Afterwards
       the shell is left, and the machine started as system service. With the
       last command a login prompt into the container is requested.
       Example 3. Exports a container image as tar file
           # machinectl export-tar fedora myfedora.tar.xz
       Exports the container "fedora" as an xz-compressed tar file
       myfedora.tar.xz into the current directory.
       Example 4. Create a new shell session
           # machinectl shell --uid=lennart
       This creates a new shell session on the local host for the user ID
       "lennart", in a su(1)-like fashion.
EXIT STATUS
       On success, 0 is returned, a non-zero failure code otherwise.
ENVIRONMENT
       $SYSTEMD_PAGER
           Pager to use when --no-pager is not given; overrides $PAGER. If
           neither $SYSTEMD_PAGER nor $PAGER are set, a set of well-known
           pager implementations are tried in turn, including less(1) and
           more(1), until one is found. If no pager implementation is
           discovered no pager is invoked. Setting this environment variable
           to an empty string or the value "cat" is equivalent to passing
           --no-pager.
       $SYSTEMD_LESS
           Override the options passed to less (by default "FRSXMK").
       $SYSTEMD_LESSCHARSET
           Override the charset passed to less (by default "utf-8", if the
           invoking terminal is determined to be UTF-8 compatible).
       $SYSTEMD_PAGERSECURE
           Takes a boolean argument. When true, the "secure" mode of the pager
           is enabled; if false, disabled. If $SYSTEMD_PAGERSECURE is not set
           at all, secure mode is enabled if the effective UID is not the same
           as the owner of the login session, see geteuid(2) and
           sd_pid_get_owner_uid(3). In secure mode, LESSSECURE=1 will be set
           when invoking the pager, and the pager shall disable commands that
           open or create new files or start new subprocesses. When
           $SYSTEMD_PAGERSECURE is not set at all, pagers which are not known
           to implement secure mode will not be used. (Currently only less(1)
           implements secure mode.)
           Note: when commands are invoked with elevated privileges, for
           example under sudo(8) or pkexec(1), care must be taken to ensure
           that unintended interactive features are not enabled. "Secure" mode
           for the pager may be enabled automatically as describe above.
           Setting SYSTEMD_PAGERSECURE=0 or not removing it from the inherited
           environment allows the user to invoke arbitrary commands. Note that
           if the $SYSTEMD_PAGER or $PAGER variables are to be honoured,
           $SYSTEMD_PAGERSECURE must be set too. It might be reasonable to
           completly disable the pager using --no-pager instead.
SEE ALSO
       systemd(1), systemd-machined.service(8), systemd-nspawn(1),
       systemd.special(7), tar(1), xz(1), gzip(1), bzip2(1)
systemd 239                                                      MACHINECTL(1)