NAME
busctl - Introspect the busSYNOPSIS
busctl
[OPTIONS...] [COMMAND] [ NAME...]
DESCRIPTION
busctl may be used to introspect and monitor the D-Bus bus.COMMANDS
The following commands are understood: listShow 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 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 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.
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.
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.
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 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.
help
Show command syntax help.
OPTIONS
The following options are understood: --address=ADDRESSConnect to the bus specified by ADDRESS
instead of using suitable defaults for either the system or user bus (see
--system and --user options).
--show-machine
When showing the list of peers, show a column
containing the names of containers they belong to. See
systemd-machined.service(8).
--unique
When showing the list of peers, 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 peers, show only
peers 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. See sd_bus_add_match(3).
--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.
-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.
--verbose
When used with the call or
get-property command, shows output in a more verbose format.
--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.
--json=MODE
When used with the call or
get-property command, shows output formatted as JSON. Expects one of
"short" (for the shortest possible output without any redundant
whitespace or line breaks) or "pretty" (for a pretty version of the
same, with indentation and line breaks). Note that transformation from D-Bus
marshalling to JSON is done in a loss-less way, which means type information
is embedded into the JSON object tree.
-j
Equivalent to --json=pretty when
invoked interactively from a terminal. Otherwise equivalent to
--json=short, in particular when the output is piped to some other
program.
--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
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".
--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".
--timeout=SECS
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.
--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".
--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.
--destination=SERVICE
Takes a service name. When used with the
emit command, a signal is emitted to the specified service.
--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=[email protected]"). 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.
-l, --full
Do not ellipsize the output in list
command.
--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
as 3 hello world foobar
a{sv} 3 One s Eins Two u 2 Yes b true
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"
$ 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"; };
# 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], sd-bus(3), systemd(1), machinectl(1), wireshark(1)NOTES
- 1.
- PCAP Next Generation (pcapng) Capture File Format
- 2.
- Type system chapter of the D-Bus specification
- 3.
- D-Bus
systemd 252 |