Systemd/man/busctl.xml

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<refentry id="busctl"
          xmlns:xi="http://www.w3.org/2001/XInclude">

  <refentryinfo>
    <title>busctl</title>
    <productname>systemd</productname>

    <authorgroup>
      <author>
        <contrib>A monkey with a typewriter</contrib>
        <firstname>Zbigniew</firstname>
        <surname>Jędrzejewski-Szmek</surname>
        <email>zbyszek@in.waw.pl</email>
      </author>
    </authorgroup>
  </refentryinfo>

  <refmeta>
    <refentrytitle>busctl</refentrytitle>
    <manvolnum>1</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>busctl</refname>
    <refpurpose>Introspect the bus</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <cmdsynopsis>
      <command>busctl</command>
      <arg choice="opt" rep="repeat">OPTIONS</arg>
      <arg choice="opt">COMMAND</arg>
      <arg choice="opt" rep="repeat"><replaceable>NAME</replaceable></arg>
    </cmdsynopsis>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para><command>busctl</command> may be used to
    introspect and monitor the D-Bus bus.</para>
  </refsect1>

  <refsect1>
    <title>Options</title>

    <para>The following options are understood:</para>

    <variablelist>
      <varlistentry>
          <term><option>--address=<replaceable>ADDRESS</replaceable></option></term>

          <listitem><para>Connect to the bus specified by
          <replaceable>ADDRESS</replaceable> instead of using suitable
          defaults for either the system or user bus (see
          <option>--system</option> and <option>--user</option>
          options).</para></listitem>
      </varlistentry>

      <varlistentry>
          <term><option>--show-machine</option></term>

          <listitem><para>When showing the list of endpoints, show a
          column containing the names of containers they belong to.
          See
          <citerefentry><refentrytitle>systemd-machined.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
          </para></listitem>
      </varlistentry>

      <varlistentry>
          <term><option>--unique</option></term>

          <listitem><para>When showing the list of endpoints, show
          only "unique" names (of the form
          <literal>:<replaceable>number</replaceable>.<replaceable>number</replaceable></literal>).
          </para></listitem>
      </varlistentry>

      <varlistentry>
          <term><option>--acquired</option></term>

          <listitem><para>The opposite of <option>--unique</option> —
          only "well-known" names will be shown.</para></listitem>
      </varlistentry>

      <varlistentry>
          <term><option>--activatable</option></term>

          <listitem><para>When showing the list of endpoints, show
          only endpoints which have actually not been activated yet,
          but may be started automatically if accessed.</para>
          </listitem>
      </varlistentry>

      <varlistentry>
          <term><option>--match=<replaceable>MATCH</replaceable></option></term>

          <listitem><para>When showing messages being exchanged, show only the
          subset matching <replaceable>MATCH</replaceable>.</para></listitem>
          <!-- TODO: link to sd_bus_add_match when it is written? -->
      </varlistentry>

      <varlistentry>
        <term><option>--no-legend</option></term>

        <listitem>
          <para>Do not print the legend,
          i.e. the column headers and the
          footer.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--size=</option></term>

        <listitem>
          <para>When used with the <command>capture</command> command
          specifies the maximum bus message size to capture
          ("snaplen"). Defaults to 4096 bytes.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--list</option></term>

        <listitem>
          <para>When used with the <command>tree</command> command shows a
          flat list of object paths instead of a tree.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--quiet</option></term>

        <listitem>
          <para>When used with the <command>call</command> 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.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--verbose</option></term>

        <listitem>
          <para>When used with the <command>call</command> or
          <command>get-property</command> command shows output in a
          more verbose format.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--expect-reply=</option><replaceable>BOOL</replaceable></term>

        <listitem>
          <para>When used with the <command>call</command> command
          specifies whether <command>busctl</command> 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 <literal>no</literal> 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 <option>--quiet</option> above. Defaults to
          <literal>yes</literal>.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--auto-start=</option><replaceable>BOOL</replaceable></term>

        <listitem>
          <para>When used with the <command>call</command> 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
          <literal>yes</literal>.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--allow-interactive-authorization=</option><replaceable>BOOL</replaceable></term>

        <listitem>
          <para>When used with the <command>call</command> command
          specifies whether the services may enforce interactive
          authorization while executing the operation, if the security
          policy is configured for this. Defaults to
          <literal>yes</literal>.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--timeout=</option><replaceable>SECS</replaceable></term>

        <listitem>
          <para>When used with the <command>call</command> 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 <option>--expect-reply=no</option> is used as the
          tool does not wait for any reply message then. When not
          specified or when set to 0 the default of
          <literal>25s</literal> is assumed.</para>
        </listitem>
      </varlistentry>

      <xi:include href="user-system-options.xml" xpointer="user" />
      <xi:include href="user-system-options.xml" xpointer="system" />
      <xi:include href="user-system-options.xml" xpointer="host" />
      <xi:include href="user-system-options.xml" xpointer="machine" />

      <xi:include href="standard-options.xml" xpointer="help" />
      <xi:include href="standard-options.xml" xpointer="version" />
      <xi:include href="standard-options.xml" xpointer="no-pager" />
    </variablelist>
  </refsect1>

  <refsect1>
    <title>Commands</title>

    <para>The following commands are understood:</para>

    <variablelist>
      <varlistentry>
        <term><command>list</command></term>

        <listitem><para>Show service names on the bus. This is the
        default if no command is specified.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>status</command> <arg choice="plain"><replaceable>SERVICE</replaceable></arg></term>

        <listitem><para>Show process information and credentials of a
        bus service.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>monitor</command> <arg choice="opt" rep="repeat"><replaceable>SERVICE</replaceable></arg></term>

        <listitem><para>Dump messages being exchanged. If
        <replaceable>SERVICE</replaceable> is specified, show messages
        to or from this endpoint. Otherwise, show all messages on the
        bus. Use Ctrl-C to terminate dump.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>capture</command> <arg choice="opt" rep="repeat"><replaceable>SERVICE</replaceable></arg></term>

        <listitem><para>Similar to <command>monitor</command> but
        writes the output in pcap format (for details see the <ulink
        url="http://wiki.wireshark.org/Development/LibpcapFileFormat">Libpcap
        File Format</ulink> description. Make sure to redirect the
        output to STDOUT to a file. Tools like
        <citerefentry><refentrytitle>wireshark</refentrytitle><manvolnum>1</manvolnum></citerefentry>
        may be used to dissect and view the generated
        files.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>tree</command> <arg choice="opt" rep="repeat"><replaceable>SERVICE</replaceable></arg></term>

        <listitem><para>Shows an object tree of one or more
        services. If <replaceable>SERVICE</replaceable> 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.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>introspect</command> <arg choice="plain"><replaceable>SERVICE</replaceable></arg> <arg choice="plain"><replaceable>OBJECT</replaceable></arg></term>

        <listitem><para>Show interfaces, methods, properties and
        signals of the specified object (identified by its path) on
        the specified service.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>call</command> <arg choice="plain"><replaceable>SERVICE</replaceable></arg> <arg choice="plain"><replaceable>OBJECT</replaceable></arg> <arg choice="plain"><replaceable>INTERFACE</replaceable></arg> <arg choice="plain"><replaceable>METHOD</replaceable></arg> <arg choice="opt"><replaceable>SIGNATURE</replaceable> <arg choice="opt" rep="repeat"><replaceable>ARGUMENT</replaceable></arg></arg></term>

        <listitem><para>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
        <option>--quiet</option> option.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>get-property</command> <arg choice="plain"><replaceable>SERVICE</replaceable></arg> <arg choice="plain"><replaceable>OBJECT</replaceable></arg> <arg choice="plain"><replaceable>INTERFACE</replaceable></arg> <arg choice="plain" rep="repeat"><replaceable>PROPERTY</replaceable></arg></term>

        <listitem><para>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 <option>--verbose</option> for a
        more elaborate output format.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>set-property</command> <arg choice="plain"><replaceable>SERVICE</replaceable></arg> <arg choice="plain"><replaceable>OBJECT</replaceable></arg> <arg choice="plain"><replaceable>INTERFACE</replaceable></arg> <arg choice="plain"><replaceable>PROPERTY</replaceable></arg> <arg choice="plain"><replaceable>SIGNATURE</replaceable></arg> <arg choice="plain" rep="repeat"><replaceable>ARGUMENT</replaceable></arg></term>

        <listitem><para>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.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>help</command></term>

        <listitem><para>Show command syntax help.</para></listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
          <title>Parameter Formatting</title>

          <para>The <command>call</command> and
          <command>set-property</command> commands take a signature
          string followed by a list of parameters formatted as string
          (for details on D-Bus signature strings see the <ulink
          url="http://dbus.freedesktop.org/doc/dbus-specification.html#type-system">Type
          system chapter of the D-Bus specification</ulink>). 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
          <literal>true</literal>, <literal>yes</literal>,
          <literal>on</literal>, <literal>1</literal>; negative
          boolean values may be specified as <literal>false</literal>,
          <literal>no</literal>, <literal>off</literal>,
          <literal>0</literal>. 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.</para>

          <para>For example,
          <programlisting>s jawoll</programlisting> is the formatting
          of a single string <literal>jawoll</literal>.</para>

          <para>
          <programlisting>as 3 hello world foobar</programlisting>
          is the formatting of a string array with three entries,
          <literal>hello</literal>, <literal>world</literal> and
          <literal>foobar</literal>.</para>

          <para>
          <programlisting>a{sv} 3 One s Eins Two u 2 Yes b true</programlisting>
          is the formatting of a dictionary
          array that maps strings to variants, consisting of three
          entries. The string <literal>One</literal> is assigned the
          string <literal>Eins</literal>. The string
          <literal>Two</literal> is assigned the 32bit unsigned
          integer 2. The string <literal>Yes</literal> is assigned a
          positive boolean.</para>

          <para>Note that the <command>call</command>,
          <command>get-property</command>,
          <command>introspect</command> commands will also generate
          output in this format for the returned data. Since this
          format is sometimes too terse to be easily understood, the
          <command>call</command> and <command>get-property</command>
          commands may generate a more verbose, multi-line output when
          passed the <option>--verbose</option> option.</para>
  </refsect1>

  <refsect1>
          <title>Examples</title>

          <example>
                  <title>Write and Read a Property</title>

                  <para>The following two commands first write a
                  property and then read it back. The property is
                  found on the
                  <literal>/org/freedesktop/systemd1</literal> object
                  of the <literal>org.freedesktop.systemd1</literal>
                  service. The name of the property is
                  <literal>LogLevel</literal> on the
                  <literal>org.freedesktop.systemd1.Manager</literal>
                  interface. The property contains a single
                  string:</para>

                  <programlisting># 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"</programlisting>

          </example>

          <example>
                  <title>Terse and Verbose Output</title>

                  <para>The following two commands read a property that
                  contains an array of strings, and first show it in
                  terse format, followed by verbose format:</para>

                  <programlisting>$ 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";
};</programlisting>
          </example>

        <example>
                  <title>Invoking a Method</title>

                  <para>The following command invokes a the
                  <literal>StartUnit</literal> method on the
                  <literal>org.freedesktop.systemd1.Manager</literal>
                  interface of the
                  <literal>/org/freedesktop/systemd1</literal> object
                  of the <literal>org.freedesktop.systemd1</literal>
                  service, and passes it two strings
                  <literal>cups.service</literal> and
                  <literal>replace</literal>. As result of the method
                  call a single object path parameter is received and
                  shown:</para>

                  <programlisting># busctl call org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager StartUnit ss "cups.service" "replace"
o "/org/freedesktop/systemd1/job/42684"</programlisting>
        </example>
  </refsect1>

  <refsect1>
    <title>See Also</title>

    <para>
      <citerefentry><refentrytitle>dbus-daemon</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <ulink url="http://freedesktop.org/wiki/Software/dbus">D-Bus</ulink>,
      <ulink url="https://code.google.com/p/d-bus/">kdbus</ulink>,
      <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd-bus-proxyd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>wireshark</refentrytitle><manvolnum>1</manvolnum></citerefentry>
    </para>
  </refsect1>
</refentry>