BUSCTL(1) busctl BUSCTL(1)
NAME
busctl - Introspect the bus
SYNOPSIS
busctl [OPTIONS...] [COMMAND] [NAME...]
DESCRIPTION
busctl may be used to introspect and monitor the D-Bus bus.
OPTIONS
The following options are understood:
--address=ADDRESS
Connect to the bus specified by ADDRESS instead of using suitable defaults for the system bus (see
--system option).
--show-machine
When showing the list of endpoints, show a column containing the names of containers they belong to. See
systemd-machined.service(8).
--unique
When showing the list of endpoints, show only "unique" names (of the form ":number.number").
--acquired
The opposite of --unique — only "well-known" names will be shown.
--activatable
When showing the list of endpoints, show only endpoints which have actually not been activated yet, but
may be started automatically if accessed.
--match=MATCH
When showing messages being exchanged, show only the subset matching MATCH.
--size=
When used with the capture command specifies the maximum bus message size to capture ("snaplen"). Defaults
to 4096 bytes.
--list
When used with the tree command shows a flat list of object paths instead of a tree.
--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.
--verbose
When used with the call or get-property command shows output in a more verbose format.
--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".
--auto-start=BOOL
--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 rest of the credential information. Defaults to "yes".
--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 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.
--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.
COMMANDS
The following commands are understood:
list
Show service names on the bus. This is the default 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 endpoint. Otherwise,
show all messages on the bus. Use Ctrl-C to terminate 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.
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.
set-property SERVICE OBJECT INTERFACE PROPERTY SIGNATURE ARGUMENT...
Set the current value an object property. Takes a service name, object path, interface name, property
name, property signature, followed by a list of parameters formatted as strings.
help
Show command syntax help.
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", "1"; negative boolean values may be
specified as "false", "no", "off", "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 32bit 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
Example 3. Invoking a Method
The following command invokes a 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 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
dbus-daemon(1), D-Bus[3], kdbus[4], sd-bus(3), systemd(1), systemd-bus-proxyd(8), machinectl(1), wireshark(1)
NOTES
1. Libpcap File Format
http://wiki.wireshark.org/Development/LibpcapFileFormat
2. Type system chapter of the D-Bus specification
http://dbus.freedesktop.org/doc/dbus-specification.html#type-system
3. D-Bus
http://freedesktop.org/wiki/Software/dbus
4. kdbus
https://code.google.com/p/d-bus/
systemd 219 BUSCTL(1)
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