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 options are understood:
16 --address=ADDRESS
18 Connect to the bus specified by ADDRESS instead of using suitable
19 defaults for either the system or user bus (see --system and --user
20 options).
21 --show-machine
23 When showing the list of peers, show a column containing the names
24 of containers they belong to. See systemd-machined.service(8).
25 --unique
27 When showing the list of peers, show only "unique" names (of the
28 form ":number.number").
29 --acquired
31 The opposite of --unique — only "well-known" names will be shown.
32 --activatable
34 When showing the list of peers, show only peers which have actually
35 not been activated yet, but may be started automatically if
36 accessed.
37 --match=MATCH
39 When showing messages being exchanged, show only the subset
40 matching MATCH. See sd_bus_add_match(3).
41 --size=
43 When used with the capture command, specifies the maximum bus
44 message size to capture ("snaplen"). Defaults to 4096 bytes.
45 --list
47 When used with the tree command, shows a flat list of object paths
48 instead of a tree.
49 -q, --quiet
51 When used with the call command, suppresses display of the response
52 message payload. Note that even if this option is specified, errors
53 returned will still be printed and the tool will indicate success
54 or failure with the process exit code.
55 --verbose
57 When used with the call or get-property command, shows output in a
58 more verbose format.
59 --xml-interface
61 When used with the introspect call, dump the XML description
62 received from the D-Bus
63 org.freedesktop.DBus.Introspectable.Introspect call instead of the
64 normal output.
65 --json=MODE
67 When used with the call or get-property command, shows output
68 formatted as JSON. Expects one of "short" (for the shortest
69 possible output without any redundant whitespace or line breaks) or
70 "pretty" (for a pretty version of the same, with indentation and
71 line breaks). Note that transformation from D-Bus marshalling to
72 JSON is done in a loss-less way, which means type information is
73 embedded into the JSON object tree.
74 -j
76 Equivalent to --json=pretty when invoked interactively from a
77 terminal. Otherwise equivalent to --json=short, in particular when
78 the output is piped to some other program.
79 --expect-reply=BOOL
81 When used with the call command, specifies whether busctl shall
82 wait for completion of the method call, output the returned method
83 response data, and return success or failure via the process exit
84 code. If this is set to "no", the method call will be issued but no
85 response is expected, the tool terminates immediately, and thus no
86 response can be shown, and no success or failure is returned via
87 the exit code. To only suppress output of the reply message
88 payload, use --quiet above. Defaults to "yes".
89 --auto-start=BOOL
91 When used with the call or emit command, specifies whether the
92 method call should implicitly activate the called service, should
93 it not be running yet but is configured to be auto-started.
94 Defaults to "yes".
95 --allow-interactive-authorization=BOOL
97 When used with the call command, specifies whether the services may
98 enforce interactive authorization while executing the operation, if
99 the security policy is configured for this. Defaults to "yes".
100 --timeout=SECS
102 When used with the call command, specifies the maximum time to wait
103 for method call completion. If no time unit is specified, assumes
104 seconds. The usual other units are understood, too (ms, us, s, min,
105 h, d, w, month, y). Note that this timeout does not apply if
106 --expect-reply=no is used, as the tool does not wait for any reply
107 message then. When not specified or when set to 0, the default of
108 "25s" is assumed.
109 --augment-creds=BOOL
111 Controls whether credential data reported by list or status shall
112 be augmented with data from /proc. When this is turned on, the data
113 shown is possibly inconsistent, as the data read from /proc might
114 be more recent than the rest of the credential information.
115 Defaults to "yes".
116 --watch-bind=BOOL
118 Controls whether to wait for the specified AF_UNIX bus socket to
119 appear in the file system before connecting to it. Defaults to off.
120 When enabled, the tool will watch the file system until the socket
121 is created and then connect to it.
122 --destination=SERVICE
124 Takes a service name. When used with the emit command, a signal is
125 emitted to the specified service.
126 --user
128 Talk to the service manager of the calling user, rather than the
129 service manager of the system.
130 --system
132 Talk to the service manager of the system. This is the implied
133 default.
134 -H, --host=
136 Execute the operation remotely. Specify a hostname, or a username
137 and hostname separated by "@", to connect to. The hostname may
138 optionally be suffixed by a port ssh is listening on, separated by
139 ":", and then a container name, separated by "/", which connects
140 directly to a specific container on the specified host. This will
141 use SSH to talk to the remote machine manager instance. Container
142 names may be enumerated with machinectl -H HOST. Put IPv6 addresses
143 in brackets.
144 -M, --machine=
146 Execute operation on a local container. Specify a container name to
147 connect to.
148 --no-pager
150 Do not pipe output into a pager.
151 --no-legend
153 Do not print the legend, i.e. column headers and the footer with
154 hints.
155 -h, --help
157 Print a short help text and exit.
158 --version
160 Print a short version string and exit.
161
163 The following commands are understood:
164 list
166 Show all peers on the bus, by their service names. By default,
167 shows both unique and well-known names, but this may be changed
168 with the --unique and --acquired switches. This is the default
169 operation if no command is specified.
170 status [SERVICE]
172 Show process information and credentials of a bus service (if one
173 is specified by its unique or well-known name), a process (if one
174 is specified by its numeric PID), or the owner of the bus (if no
175 parameter is specified).
176 monitor [SERVICE...]
178 Dump messages being exchanged. If SERVICE is specified, show
179 messages to or from this peer, identified by its well-known or
180 unique name. Otherwise, show all messages on the bus. Use Ctrl+C to
181 terminate the dump.
182 capture [SERVICE...]
184 Similar to monitor but writes the output in pcap format (for
185 details, see the Libpcap File Format[1] description). Make sure to
186 redirect standard output to a file. Tools like wireshark(1) may be
187 used to dissect and view the resulting files.
188 tree [SERVICE...]
190 Shows an object tree of one or more services. If SERVICE is
191 specified, show object tree of the specified services only.
192 Otherwise, show all object trees of all services on the bus that
193 acquired at least one well-known name.
194 introspect SERVICE OBJECT [INTERFACE]
196 Show interfaces, methods, properties and signals of the specified
197 object (identified by its path) on the specified service. If the
198 interface argument is passed, the output is limited to members of
199 the specified interface.
200 call SERVICE OBJECT INTERFACE METHOD [SIGNATURE [ARGUMENT...]]
202 Invoke a method and show the response. Takes a service name, object
203 path, interface name and method name. If parameters shall be passed
204 to the method call, a signature string is required, followed by the
205 arguments, individually formatted as strings. For details on the
206 formatting used, see below. To suppress output of the returned
207 data, use the --quiet option.
208 emit OBJECT INTERFACE SIGNAL [SIGNATURE [ARGUMENT...]]
210 Emit a signal. Takes a object path, interface name and method name.
211 If parameters shall be passed, a signature string is required,
212 followed by the arguments, individually formatted as strings. For
213 details on the formatting used, see below. To specify the
214 destination of the signal, use the --destination= option.
215 get-property SERVICE OBJECT INTERFACE PROPERTY...
217 Retrieve the current value of one or more object properties. Takes
218 a service name, object path, interface name and property name.
219 Multiple properties may be specified at once, in which case their
220 values will be shown one after the other, separated by newlines.
221 The output is, by default, in terse format. Use --verbose for a
222 more elaborate output format.
223 set-property SERVICE OBJECT INTERFACE PROPERTY SIGNATURE ARGUMENT...
225 Set the current value of an object property. Takes a service name,
226 object path, interface name, property name, property signature,
227 followed by a list of parameters formatted as strings.
228 help
230 Show command syntax help.
231
233 The call and set-property commands take a signature string followed by
234 a list of parameters formatted as string (for details on D-Bus
235 signature strings, see the Type system chapter of the D-Bus
236 specification[2]). For simple types, each parameter following the
237 signature should simply be the parameter's value formatted as string.
238 Positive boolean values may be formatted as "true", "yes", "on", or
239 "1"; negative boolean values may be specified as "false", "no", "off",
240 or "0". For arrays, a numeric argument for the number of entries
241 followed by the entries shall be specified. For variants, the signature
242 of the contents shall be specified, followed by the contents. For
243 dictionaries and structs, the contents of them shall be directly
244 specified.
245 For example,
247 s jawoll
249 is the formatting of a single string "jawoll".
251 as 3 hello world foobar
253 is the formatting of a string array with three entries, "hello",
255 "world" and "foobar".
256 a{sv} 3 One s Eins Two u 2 Yes b true
258 is the formatting of a dictionary array that maps strings to variants,
260 consisting of three entries. The string "One" is assigned the string
261 "Eins". The string "Two" is assigned the 32-bit unsigned integer 2. The
262 string "Yes" is assigned a positive boolean.
263 Note that the call, get-property, introspect commands will also
265 generate output in this format for the returned data. Since this format
266 is sometimes too terse to be easily understood, the call and
267 get-property commands may generate a more verbose, multi-line output
268 when passed the --verbose option.
269
271 Example 1. Write and Read a Property
272 The following two commands first write a property and then read it
274 back. The property is found on the "/org/freedesktop/systemd1" object
275 of the "org.freedesktop.systemd1" service. The name of the property is
276 "LogLevel" on the "org.freedesktop.systemd1.Manager" interface. The
277 property contains a single string:
278 # busctl set-property org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager LogLevel s debug
280 # busctl get-property org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager LogLevel
281 s "debug"
282 Example 2. Terse and Verbose Output
284 The following two commands read a property that contains an array of
286 strings, and first show it in terse format, followed by verbose format:
287 $ busctl get-property org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager Environment
289 as 2 "LANG=en_US.UTF-8" "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin"
290 $ busctl get-property --verbose org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager Environment
291 ARRAY "s" {
292 STRING "LANG=en_US.UTF-8";
293 STRING "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin";
294 };
295 Example 3. Invoking a Method
297 The following command invokes the "StartUnit" method on the
299 "org.freedesktop.systemd1.Manager" interface of the
300 "/org/freedesktop/systemd1" object of the "org.freedesktop.systemd1"
301 service, and passes it two strings "cups.service" and "replace". As a
302 result of the method call, a single object path parameter is received
303 and shown:
304 # busctl call org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager StartUnit ss "cups.service" "replace"
306 o "/org/freedesktop/systemd1/job/42684"
307
309 dbus-daemon(1), D-Bus[3], sd-bus(3), systemd(1), machinectl(1),
310 wireshark(1)
311
313 1. Libpcap File Format
314 https://wiki.wireshark.org/Development/LibpcapFileFormat
315 2. Type system chapter of the D-Bus specification
317 http://dbus.freedesktop.org/doc/dbus-specification.html#type-system
318 3. D-Bus
320 https://www.freedesktop.org/wiki/Software/dbus
321systemd 243 BUSCTL(1)