busctl - Introspect the bus


   busctl [OPTIONS...] [COMMAND] [NAME...]


   busctl may be used to introspect and monitor the D-Bus bus.


   The following options are understood:

       Connect to the bus specified by ADDRESS instead of using suitable
       defaults for either the system or user bus (see --system and --user

       When showing the list of peers, show a column containing the names
       of containers they belong to. See systemd-machined.service(8).

       When showing the list of peers, show only "unique" names (of the
       form ":number.number").

       The opposite of --unique --- only "well-known" names will be shown.

       When showing the list of peers, show only peers which have actually
       not been activated yet, but may be started automatically if

       When showing messages being exchanged, show only the subset
       matching MATCH. See sd_bus_add_match(3).

       When used with the capture command, specifies the maximum bus
       message size to capture ("snaplen"). Defaults to 4096 bytes.

       When used with the tree command, shows a flat list of object paths
       instead of a tree.

       When used with the call command, suppresses display of the response
       message payload. Note that even if this option is specified, errors
       returned will still be printed and the tool will indicate success
       or failure with the process exit code.

       When used with the call or get-property command, shows output in a
       more verbose format.

       When used with the call command, specifies whether busctl shall
       wait for completion of the method call, output the returned method
       response data, and return success or failure via the process exit
       code. If this is set to "no", the method call will be issued but no
       response is expected, the tool terminates immediately, and thus no
       response can be shown, and no success or failure is returned via
       the exit code. To only suppress output of the reply message
       payload, use --quiet above. Defaults to "yes".

       When used with the call command, specifies whether the method call
       should implicitly activate the called service, should it not be
       running yet but is configured to be auto-started. Defaults to

       When used with the call command, specifies whether the services may
       enforce interactive authorization while executing the operation, if
       the security policy is configured for this. Defaults to "yes".

       When used with the call command, specifies the maximum time to wait
       for method call completion. If no time unit is specified, assumes
       seconds. The usual other units are understood, too (ms, us, s, min,
       h, d, w, month, y). Note that this timeout does not apply if
       --expect-reply=no is used, as the tool does not wait for any reply
       message then. When not specified or when set to 0, the default of
       "25s" is assumed.

       Controls whether credential data reported by list or status shall
       be augmented with data from /proc. When this is turned on, the data
       shown is possibly inconsistent, as the data read from /proc might
       be more recent than the rest of the credential information.
       Defaults to "yes".

       Talk to the service manager of the calling user, rather than the
       service manager of the system.

       Talk to the service manager of the system. This is the implied

   -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=
       Execute operation on a local container. Specify a container name to
       connect to.

       Do not pipe output into a pager.

       Do not print the legend, i.e. column headers and the footer with

   -h, --help
       Print a short help text and exit.

       Print a short version string and exit.


   The following commands are understood:

       Show all peers on the bus, by their service names. By default,
       shows both unique and well-known names, but this may be changed
       with the --unique and --acquired switches. This is the default
       operation if no command is specified.

   status [SERVICE]
       Show process information and credentials of a bus service (if one
       is specified by its unique or well-known name), a process (if one
       is specified by its numeric PID), or the owner of the bus (if no
       parameter is specified).

   monitor [SERVICE...]
       Dump messages being exchanged. If SERVICE is specified, show
       messages to or from this peer, identified by its well-known or
       unique name. Otherwise, show all messages on the bus. Use Ctrl-C to
       terminate the dump.

   capture [SERVICE...]
       Similar to monitor but writes the output in pcap format (for
       details, see the Libpcap File Format[1] description. Make sure to
       redirect the output to STDOUT to a file. Tools like wireshark(1)
       may be used to dissect and view the generated files.

   tree [SERVICE...]
       Shows an object tree of one or more services. If SERVICE is
       specified, show object tree of the specified services only.
       Otherwise, show all object trees of all services on the bus that
       acquired at least one well-known name.

       Show interfaces, methods, properties and signals of the specified
       object (identified by its path) on the specified service. If the
       interface argument is passed, the output is limited to members of
       the specified interface.

       Invoke a method and show the response. Takes a service name, object
       path, interface name and method name. If parameters shall be passed
       to the method call, a signature string is required, followed by the
       arguments, individually formatted as strings. For details on the
       formatting used, see below. To suppress output of the returned
       data, use the --quiet option.

       Retrieve the current value of one or more object properties. Takes
       a service name, object path, interface name and property name.
       Multiple properties may be specified at once, in which case their
       values will be shown one after the other, separated by newlines.
       The output is, by default, in terse format. Use --verbose for a
       more elaborate output format.

       Set the current value of an object property. Takes a service name,
       object path, interface name, property name, property signature,
       followed by a list of parameters formatted as strings.

       Show command syntax help.


   The call and set-property commands take a signature string followed by
   a list of parameters formatted as string (for details on D-Bus
   signature strings, see the Type system chapter of the D-Bus
   specification[2]). For simple types, each parameter following the
   signature should simply be the parameter's value formatted as string.
   Positive boolean values may be formatted as "true", "yes", "on", or
   "1"; negative boolean values may be specified as "false", "no", "off",
   or "0". For arrays, a numeric argument for the number of entries
   followed by the entries shall be specified. For variants, the signature
   of the contents shall be specified, followed by the contents. For
   dictionaries and structs, the contents of them shall be directly

   For example,

       s jawoll

   is the formatting of a single string "jawoll".

       as 3 hello world foobar

   is the formatting of a string array with three entries, "hello",
   "world" and "foobar".

       a{sv} 3 One s Eins Two u 2 Yes b true

   is the formatting of a dictionary array that maps strings to variants,
   consisting of three entries. The string "One" is assigned the string
   "Eins". The string "Two" is assigned the 32-bit unsigned integer 2. The
   string "Yes" is assigned a positive boolean.

   Note that the call, get-property, introspect commands will also
   generate output in this format for the returned data. Since this format
   is sometimes too terse to be easily understood, the call and
   get-property commands may generate a more verbose, multi-line output
   when passed the --verbose option.


   Example 1. Write and Read a Property

   The following two commands first write a property and then read it
   back. The property is found on the "/org/freedesktop/systemd1" object
   of the "org.freedesktop.systemd1" service. The name of the property is
   "LogLevel" on the "org.freedesktop.systemd1.Manager" interface. The
   property contains a single string:

       # busctl set-property org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager LogLevel s debug
       # busctl get-property org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager LogLevel
       s "debug"

   Example 2. Terse and Verbose Output

   The following two commands read a property that contains an array of
   strings, and first show it in terse format, followed by verbose format:

       $ busctl get-property org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager Environment
       as 2 "LANG=en_US.UTF-8" "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin"
       $ busctl get-property --verbose org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager Environment
       ARRAY "s" {
               STRING "LANG=en_US.UTF-8";
               STRING "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin";

   Example 3. Invoking a Method

   The following command invokes the "StartUnit" method on the
   "org.freedesktop.systemd1.Manager" interface of the
   "/org/freedesktop/systemd1" object of the "org.freedesktop.systemd1"
   service, and passes it two strings "cups.service" and "replace". As a
   result of the method call, a single object path parameter is received
   and shown:

       # busctl call org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager StartUnit ss "cups.service" "replace"
       o "/org/freedesktop/systemd1/job/42684"


   dbus-daemon(1), D-Bus[3], sd-bus(3), systemd(1), machinectl(1),


    1. Libpcap File Format

    2. Type system chapter of the D-Bus specification

    3. D-Bus


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