1BUSCTL(1) busctl BUSCTL(1)
2
6 busctl - Introspect the bus
7
9 busctl [OPTIONS...] [COMMAND] [NAME...]
10
12 busctl may be used to introspect and monitor the D-Bus bus.
13
15 The following commands are understood:
16 list
18 Show all peers on the bus, by their service names. By default,
19 shows both unique and well-known names, but this may be changed
20 with the --unique and --acquired switches. This is the default
21 operation if no command is specified.
22 status [SERVICE]
24 Show process information and credentials of a bus service (if one
25 is specified by its unique or well-known name), a process (if one
26 is specified by its numeric PID), or the owner of the bus (if no
27 parameter is specified).
28 monitor [SERVICE...]
30 Dump messages being exchanged. If SERVICE is specified, show
31 messages to or from this peer, identified by its well-known or
32 unique name. Otherwise, show all messages on the bus. Use Ctrl+C to
33 terminate the dump.
34 capture [SERVICE...]
36 Similar to monitor but writes the output in pcapng format (for
37 details, see PCAP Next Generation (pcapng) Capture File Format[1]).
38 Make sure to redirect standard output to a file or pipe. Tools like
39 wireshark(1) may be used to dissect and view the resulting files.
40 tree [SERVICE...]
42 Shows an object tree of one or more services. If SERVICE is
43 specified, show object tree of the specified services only.
44 Otherwise, show all object trees of all services on the bus that
45 acquired at least one well-known name.
46 introspect SERVICE OBJECT [INTERFACE]
48 Show interfaces, methods, properties and signals of the specified
49 object (identified by its path) on the specified service. If the
50 interface argument is passed, the output is limited to members of
51 the specified interface.
52 call SERVICE OBJECT INTERFACE METHOD [SIGNATURE [ARGUMENT...]]
54 Invoke a method and show the response. Takes a service name, object
55 path, interface name and method name. If parameters shall be passed
56 to the method call, a signature string is required, followed by the
57 arguments, individually formatted as strings. For details on the
58 formatting used, see below. To suppress output of the returned
59 data, use the --quiet option.
60 emit OBJECT INTERFACE SIGNAL [SIGNATURE [ARGUMENT...]]
62 Emit a signal. Takes an object path, interface name and method
63 name. If parameters shall be passed, a signature string is
64 required, followed by the arguments, individually formatted as
65 strings. For details on the formatting used, see below. To specify
66 the destination of the signal, use the --destination= option.
67 get-property SERVICE OBJECT INTERFACE PROPERTY...
69 Retrieve the current value of one or more object properties. Takes
70 a service name, object path, interface name and property name.
71 Multiple properties may be specified at once, in which case their
72 values will be shown one after the other, separated by newlines.
73 The output is, by default, in terse format. Use --verbose for a
74 more elaborate output format.
75 set-property SERVICE OBJECT INTERFACE PROPERTY SIGNATURE ARGUMENT...
77 Set the current value of an object property. Takes a service name,
78 object path, interface name, property name, property signature,
79 followed by a list of parameters formatted as strings.
80 help
82 Show command syntax help.
83
85 The following options are understood:
86 --address=ADDRESS
88 Connect to the bus specified by ADDRESS instead of using suitable
89 defaults for either the system or user bus (see --system and --user
90 options).
91 --show-machine
93 When showing the list of peers, show a column containing the names
94 of containers they belong to. See systemd-machined.service(8).
95 --unique
97 When showing the list of peers, show only "unique" names (of the
98 form ":number.number").
99 --acquired
101 The opposite of --unique — only "well-known" names will be shown.
102 --activatable
104 When showing the list of peers, show only peers which have actually
105 not been activated yet, but may be started automatically if
106 accessed.
107 --match=MATCH
109 When showing messages being exchanged, show only the subset
110 matching MATCH. See sd_bus_add_match(3).
111 --size=
113 When used with the capture command, specifies the maximum bus
114 message size to capture ("snaplen"). Defaults to 4096 bytes.
115 --list
117 When used with the tree command, shows a flat list of object paths
118 instead of a tree.
119 -q, --quiet
121 When used with the call command, suppresses display of the response
122 message payload. Note that even if this option is specified, errors
123 returned will still be printed and the tool will indicate success
124 or failure with the process exit code.
125 --verbose
127 When used with the call or get-property command, shows output in a
128 more verbose format.
129 --xml-interface
131 When used with the introspect call, dump the XML description
132 received from the D-Bus
133 org.freedesktop.DBus.Introspectable.Introspect call instead of the
134 normal output.
135 --json=MODE
137 When used with the call or get-property command, shows output
138 formatted as JSON. Expects one of "short" (for the shortest
139 possible output without any redundant whitespace or line breaks) or
140 "pretty" (for a pretty version of the same, with indentation and
141 line breaks). Note that transformation from D-Bus marshalling to
142 JSON is done in a loss-less way, which means type information is
143 embedded into the JSON object tree.
144 -j
146 Equivalent to --json=pretty when invoked interactively from a
147 terminal. Otherwise equivalent to --json=short, in particular when
148 the output is piped to some other program.
149 --expect-reply=BOOL
151 When used with the call command, specifies whether busctl shall
152 wait for completion of the method call, output the returned method
153 response data, and return success or failure via the process exit
154 code. If this is set to "no", the method call will be issued but no
155 response is expected, the tool terminates immediately, and thus no
156 response can be shown, and no success or failure is returned via
157 the exit code. To only suppress output of the reply message
158 payload, use --quiet above. Defaults to "yes".
159 --auto-start=BOOL
161 When used with the call or emit command, specifies whether the
162 method call should implicitly activate the called service, should
163 it not be running yet but is configured to be auto-started.
164 Defaults to "yes".
165 --allow-interactive-authorization=BOOL
167 When used with the call command, specifies whether the services may
168 enforce interactive authorization while executing the operation, if
169 the security policy is configured for this. Defaults to "yes".
170 --timeout=SECS
172 When used with the call command, specifies the maximum time to wait
173 for method call completion. If no time unit is specified, assumes
174 seconds. The usual other units are understood, too (ms, us, s, min,
175 h, d, w, month, y). Note that this timeout does not apply if
176 --expect-reply=no is used, as the tool does not wait for any reply
177 message then. When not specified or when set to 0, the default of
178 "25s" is assumed.
179 --augment-creds=BOOL
181 Controls whether credential data reported by list or status shall
182 be augmented with data from /proc/. When this is turned on, the
183 data shown is possibly inconsistent, as the data read from /proc/
184 might be more recent than the rest of the credential information.
185 Defaults to "yes".
186 --watch-bind=BOOL
188 Controls whether to wait for the specified AF_UNIX bus socket to
189 appear in the file system before connecting to it. Defaults to off.
190 When enabled, the tool will watch the file system until the socket
191 is created and then connect to it.
192 --destination=SERVICE
194 Takes a service name. When used with the emit command, a signal is
195 emitted to the specified service.
196 --user
198 Talk to the service manager of the calling user, rather than the
199 service manager of the system.
200 --system
202 Talk to the service manager of the system. This is the implied
203 default.
204 -H, --host=
206 Execute the operation remotely. Specify a hostname, or a username
207 and hostname separated by "@", to connect to. The hostname may
208 optionally be suffixed by a port ssh is listening on, separated by
209 ":", and then a container name, separated by "/", which connects
210 directly to a specific container on the specified host. This will
211 use SSH to talk to the remote machine manager instance. Container
212 names may be enumerated with machinectl -H HOST. Put IPv6 addresses
213 in brackets.
214 -M, --machine=
216 Execute operation on a local container. Specify a container name to
217 connect to, optionally prefixed by a user name to connect as and a
218 separating "@" character. If the special string ".host" is used in
219 place of the container name, a connection to the local system is
220 made (which is useful to connect to a specific user's user bus:
221 "--user --machine=lennart@.host"). If the "@" syntax is not used,
222 the connection is made as root user. If the "@" syntax is used
223 either the left hand side or the right hand side may be omitted
224 (but not both) in which case the local user name and ".host" are
225 implied.
226 -l, --full
228 Do not ellipsize the output in list command.
229 --no-pager
231 Do not pipe output into a pager.
232 --no-legend
234 Do not print the legend, i.e. column headers and the footer with
235 hints.
236 -h, --help
238 Print a short help text and exit.
239 --version
241 Print a short version string and exit.
242
244 The call and set-property commands take a signature string followed by
245 a list of parameters formatted as string (for details on D-Bus
246 signature strings, see the Type system chapter of the D-Bus
247 specification[2]). For simple types, each parameter following the
248 signature should simply be the parameter's value formatted as string.
249 Positive boolean values may be formatted as "true", "yes", "on", or
250 "1"; negative boolean values may be specified as "false", "no", "off",
251 or "0". For arrays, a numeric argument for the number of entries
252 followed by the entries shall be specified. For variants, the signature
253 of the contents shall be specified, followed by the contents. For
254 dictionaries and structs, the contents of them shall be directly
255 specified.
256 For example,
258 s jawoll
260 is the formatting of a single string "jawoll".
262 as 3 hello world foobar
264 is the formatting of a string array with three entries, "hello",
266 "world" and "foobar".
267 a{sv} 3 One s Eins Two u 2 Yes b true
269 is the formatting of a dictionary array that maps strings to variants,
271 consisting of three entries. The string "One" is assigned the string
272 "Eins". The string "Two" is assigned the 32-bit unsigned integer 2. The
273 string "Yes" is assigned a positive boolean.
274 Note that the call, get-property, introspect commands will also
276 generate output in this format for the returned data. Since this format
277 is sometimes too terse to be easily understood, the call and
278 get-property commands may generate a more verbose, multi-line output
279 when passed the --verbose option.
280
282 Example 1. Write and Read a Property
283 The following two commands first write a property and then read it
285 back. The property is found on the "/org/freedesktop/systemd1" object
286 of the "org.freedesktop.systemd1" service. The name of the property is
287 "LogLevel" on the "org.freedesktop.systemd1.Manager" interface. The
288 property contains a single string:
289 # busctl set-property org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager LogLevel s debug
291 # busctl get-property org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager LogLevel
292 s "debug"
293 Example 2. Terse and Verbose Output
295 The following two commands read a property that contains an array of
297 strings, and first show it in terse format, followed by verbose format:
298 $ busctl get-property org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager Environment
300 as 2 "LANG=en_US.UTF-8" "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin"
301 $ busctl get-property --verbose org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager Environment
302 ARRAY "s" {
303 STRING "LANG=en_US.UTF-8";
304 STRING "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin";
305 };
306 Example 3. Invoking a Method
308 The following command invokes the "StartUnit" method on the
310 "org.freedesktop.systemd1.Manager" interface of the
311 "/org/freedesktop/systemd1" object of the "org.freedesktop.systemd1"
312 service, and passes it two strings "cups.service" and "replace". As a
313 result of the method call, a single object path parameter is received
314 and shown:
315 # busctl call org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager StartUnit ss "cups.service" "replace"
317 o "/org/freedesktop/systemd1/job/42684"
318
320 dbus-daemon(1), D-Bus[3], sd-bus(3), systemd(1), machinectl(1),
321 wireshark(1)
322
324 1. PCAP Next Generation (pcapng) Capture File Format
325 https://github.com/pcapng/pcapng/
326 2. Type system chapter of the D-Bus specification
328 https://dbus.freedesktop.org/doc/dbus-specification.html#type-system
329 3. D-Bus
331 https://www.freedesktop.org/wiki/Software/dbus
332systemd 253 BUSCTL(1)