BUSCTL(1)                          busctl                          BUSCTL(1)

NAME         top

       busctl - Introspect the bus

SYNOPSIS         top

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

DESCRIPTION         top

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

OPTIONS         top

       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 options).

           When showing the list of peers, show a column containing the
           names of containers they belong to. See

           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 accessed.

           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

       -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.

COMMANDS         top

       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 standard output to a file. Tools like wireshark(1)
           may be used to dissect and view the resulting 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.

       introspect SERVICE OBJECT [INTERFACE]
           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 specified.

       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.

EXAMPLES         top

       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

           $ 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"

SEE ALSO         top

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

NOTES         top

        1. Libpcap File Format

        2. Type system chapter of the D-Bus specification

        3. D-Bus

COLOPHON         top

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       ⟨⟩.  This
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systemd 234                                                        BUSCTL(1)

Pages that refer to this page: sd-bus(3)systemd.directives(7)systemd.index(7)