# busctl

## NAME



           busctl - Introspect the bus
    


## SYNOPSIS



    
           **busctl**[OPTIONS...] [COMMAND] [_NAME_...]
    


## DESCRIPTION



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


## COMMANDS



           The following commands are understood:
    
           **list**
               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.
    
               Added in version 209.
    
           **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).
    
               Added in version 209.
    
           **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.
    
               Added in version 209.
    
           **capture**[_SERVICE_...]
               Similar to **monitor** but writes the output in pcapng format (for
               details, see **PCAP Next Generation (pcapng) Capture File**
               **Format******[1]). Make sure to redirect standard output to a file or
               pipe. Tools likewireshark(1) may be used to dissect and view
               the resulting files.
    
               Added in version 218.
    
           **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.
    
               Added in version 218.
    
           **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.
    
               Added in version 218.
    
           **call** _SERVICE OBJECT INTERFACE METHOD_ [_SIGNATURE_ [_ARGUMENT_...]]
               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.
    
               Added in version 218.
    
           **emit** _OBJECT INTERFACE SIGNAL_ [_SIGNATURE_ [_ARGUMENT_...]]
               Emit a signal. Takes an object path, interface name and method
               name. If parameters shall be passed, a signature string is
               required, followed by the arguments, individually formatted as
               strings. For details on the formatting used, see below. To
               specify the destination of the signal, use the **--destination=**
               option.
    
               Added in version 242.
    
           **wait**[_SERVICE_] _OBJECT INTERFACE SIGNAL_
               Wait for a signal. Takes an object path, interface name, and
               signal name. To suppress output of the returned data, use the
               **--quiet** option. The service name may be omitted, in which case
               **busctl** will match signals from any sender.
    
               Added in version 257.
    
           **get-property** _SERVICE OBJECT INTERFACE PROPERTY_...
               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.
    
               Added in version 218.
    
           **set-property** _SERVICE OBJECT INTERFACE PROPERTY SIGNATURE_
           _ARGUMENT_...
               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.
    
               Added in version 218.
    
           **help**
               Show command syntax help.
    
               Added in version 209.
    


## OPTIONS



           The following options are understood:
    
           **--address=**_ADDRESS_
               Connect to the bus specified by _ADDRESS_ instead of using
               suitable defaults for either the system or user bus (see
               **--system** and **--user** options).
    
               Added in version 209.
    
           **--show-machine**
               When showing the list of peers, show a column containing the
               names of containers they belong to. See
               systemd-machined.service(8).
    
               Added in version 209.
    
           **--unique**
               When showing the list of peers, show only "unique" names (of
               the form ":_number_._number_ ").
    
               Added in version 209.
    
           **--acquired**
               The opposite of **--unique** — only "well-known" names will be
               shown.
    
               Added in version 209.
    
           **--activatable**
               When showing the list of peers, show only peers which have
               actually not been activated yet, but may be started
               automatically if accessed.
    
               Added in version 209.
    
           **--match=**_MATCH_
               When showing messages being exchanged, show only the subset
               matching _MATCH_. See sd_bus_add_match(3).
    
               Added in version 209.
    
           **--size=**
               When used with the **capture** command, specifies the maximum bus
               message size to capture ("snaplen"). Defaults to 4096 bytes.
    
               Added in version 218.
    
           **--list**
               When used with the **tree** command, shows a flat list of object
               paths instead of a tree.
    
               Added in version 218.
    
           **-q** , **--quiet**
               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.
    
               Added in version 218.
    
           **--verbose**
               When used with the **call** or **get-property** command, shows output
               in a more verbose format.
    
               Added in version 218.
    
           **--xml-interface**
               When used with the **introspect** call, dump the XML description
               received from the D-Bus
               **org.freedesktop.DBus.Introspectable.Introspect** call instead of
               the normal output.
    
               Added in version 243.
    
           **--expect-reply=**_BOOL_
               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".
    
               Added in version 218.
    
           **--auto-start=**_BOOL_
               When used with the **call** or **emit** 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 "yes".
    
               Added in version 218.
    
           **--allow-interactive-authorization=**_BOOL_
               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".
    
               Added in version 218.
    
           **--timeout=**_SECS_
               When used with the **call** command, specifies the maximum time to
               wait for method call completion. When used with the **monitor**
               command, since version v257, specifies the maximum time to
               wait for messages before automatically exiting. 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, when
               combined with the **call** command, 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 for the **call** command, and it
               is disabled for the **monitor** command.
    
               Added in version 218.
    
           **--limit-messages=**_NUMBER_ , **-N** _NUMBER_
               When used with the **monitor** command, if enabled will make
               **busctl** exit when the specified number of messages have been
               received and printed. This is useful in combination with
               **--match=** , to wait for the specified number of occurrences of
               specific D-Bus messages.
    
               Added in version 257.
    
           **--augment-creds=**_BOOL_
               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".
    
               Added in version 218.
    
           **--watch-bind=**_BOOL_
               Controls whether to wait for the specified **AF_UNIX** bus socket
               to appear in the file system before connecting to it. Defaults
               to off. When enabled, the tool will watch the file system
               until the socket is created and then connect to it.
    
               Added in version 237.
    
           **--destination=**_SERVICE_
               Takes a service name. When used with the **emit** command, a
               signal is emitted to the specified service.
    
               Added in version 242.
    
           **--user**
               Talk to the service manager of the calling user, rather than
               the service manager of the system.
    
           **--system**
               Talk to the service manager of the system. This is the implied
               default.
    
           **-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.
    
           **-C** , **--capsule=**
               Execute operation on a capsule. Specify a capsule name to
               connect to. See capsule@.service(5) for details about
               capsules.
    
               Added in version 256.
    
           **-l** , **--full**
               Do not ellipsize the output in **list** command.
    
               Added in version 245.
    
           **--json=**_MODE_
               Shows output formatted as JSON. Expects one of "short" (for
               the shortest possible output without any redundant whitespace
               or line breaks), "pretty" (for a pretty version of the same,
               with indentation and line breaks) or "off" (to turn off JSON
               output, the default).
    
           **-j**
               Equivalent to **--json=pretty** if running on a terminal, and
               **--json=short** otherwise.
    
           **--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.
    
           **-h** , **--help**
               Print a short help text and exit.
    
           **--version**
               Print a short version string and exit.
    


## PARAMETER FORMATTING



           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



           **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"
    


## NOTES



            1. PCAP Next Generation (pcapng) Capture File Format
               https://github.com/pcapng/pcapng/
    
            2. Type system chapter of the D-Bus specification
               https://dbus.freedesktop.org/doc/dbus-specification.html#type-system
    
            3. D-Bus
               https://www.freedesktop.org/wiki/Software/dbus
    


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