APUE Learning Example Source Code
guowenxue
2019-06-26 157be0b0d4c7d4809cfcafc76235cc18388378c8
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<?xml version='1.0' encoding='UTF-8'?>
<?xml-stylesheet type="text/xsl" href="manpage.xsl"?>
 
<refentry xml:id="mosquitto_rr" xmlns:xlink="http://www.w3.org/1999/xlink">
    <refmeta>
        <refentrytitle>mosquitto_rr</refentrytitle>
        <manvolnum>1</manvolnum>
        <refmiscinfo class="source">Mosquitto Project</refmiscinfo>
        <refmiscinfo class="manual">Commands</refmiscinfo>
    </refmeta>
 
    <refnamediv>
        <refname>mosquitto_rr</refname>
        <refpurpose>an MQTT version 5/3.1.1 client for request/response messaging</refpurpose>
    </refnamediv>
 
    <refsynopsisdiv>
        <cmdsynopsis>
            <command>mosquitto_rr</command>
            <group choice='req'>
                <arg choice='plain'>
                    <arg><option>-h</option> <replaceable>hostname</replaceable></arg>
                    <arg><option>-p</option> <replaceable>port-number</replaceable></arg>
                    <arg><option>-u</option> <replaceable>username</replaceable></arg>
                    <arg><option>-P</option> <replaceable>password</replaceable></arg>
                    <arg choice='plain' rep='repeat'><option>-t</option> <replaceable>message-topic</replaceable></arg>
                </arg>
                <arg choice='plain'>
                    <arg choice='plain'><option>-L</option> <replaceable>URL</replaceable></arg>
                    <arg choice='opt' rep='repeat'><option>-t</option> <replaceable>message-topic</replaceable></arg>
                </arg>
                <arg><option>-e</option> <replaceable>response-topic</replaceable></arg>
            </group>
            <group choice='req'>
                <arg choice='plain'><option>-f</option> <replaceable>file</replaceable></arg>
                <arg choice='plain'><option>-m</option> <replaceable>message</replaceable></arg>
                <arg choice='plain'><option>-n</option></arg>
                <arg choice='plain'><option>-s</option></arg>
            </group>
            <arg><option>-A</option> <replaceable>bind-address</replaceable></arg>
            <arg><option>-c</option></arg>
            <arg><option>-d</option></arg>
            <arg><option>-D</option> <replaceable>command</replaceable> <replaceable>identifier</replaceable> <replaceable>value</replaceable></arg>
            <arg><option>-i</option> <replaceable>client-id</replaceable></arg>
            <arg><option>-I</option> <replaceable>client-id-prefix</replaceable></arg>
            <arg><option>-k</option> <replaceable>keepalive-time</replaceable></arg>
            <arg><option>-N</option></arg>
            <arg><option>-q</option> <replaceable>message-QoS</replaceable></arg>
            <arg><option>-R</option></arg>
            <arg><option>-S</option></arg>
            <arg><option>-v</option></arg>
            <arg><option>-V</option> <replaceable>protocol-version</replaceable></arg>
            <arg><option>-W</option> <replaceable>message-processing-timeout</replaceable></arg>
            <arg><option>--proxy</option> <replaceable>socks-url</replaceable></arg>
            <arg><option>--quiet</option></arg>
            <arg>
                <option>--will-topic</option> <replaceable>topic</replaceable>
                <arg><option>--will-payload</option> <replaceable>payload</replaceable></arg>
                <arg><option>--will-qos</option> <replaceable>qos</replaceable></arg>
                <arg><option>--will-retain</option></arg>
            </arg>
            <group>
                <arg>
                    <group choice='req'>
                        <arg choice='plain'><option>--cafile</option> <replaceable>file</replaceable></arg>
                        <arg choice='plain'><option>--capath</option> <replaceable>dir</replaceable></arg>
                    </group>
                    <arg><option>--cert</option> <replaceable>file</replaceable></arg>
                    <arg><option>--key</option> <replaceable>file</replaceable></arg>
                    <arg><option>--ciphers</option> <replaceable>ciphers</replaceable></arg>
                    <arg><option>--tls-version</option> <replaceable>version</replaceable></arg>
                    <arg><option>--tls-alpn</option> <replaceable>protocol</replaceable></arg>
                    <arg><option>--tls-engine</option> <replaceable>engine</replaceable></arg>
                    <arg><option>--keyform</option>
                    <group choice='req'>
                        <arg choice='plain'><replaceable>pem</replaceable></arg>
                        <arg choice='plain'><replaceable>engine</replaceable></arg>
                    </group></arg>
                    <arg><option>--tls-engine-kpass-sha1</option> <replaceable>kpass-sha1</replaceable></arg>
                    <arg><option>--insecure</option></arg>
                </arg>
                <arg>
                    <arg choice='plain'><option>--psk</option> <replaceable>hex-key</replaceable></arg>
                    <arg choice='plain'><option>--psk-identity</option> <replaceable>identity</replaceable></arg>
                    <arg><option>--ciphers</option> <replaceable>ciphers</replaceable></arg>
                    <arg><option>--tls-version</option> <replaceable>version</replaceable></arg>
                </arg>
            </group>
        </cmdsynopsis>
        <cmdsynopsis>
            <command>mosquitto_rr</command>
            <group choice='plain'>
                <arg><option>--help</option></arg>
            </group>
        </cmdsynopsis>
    </refsynopsisdiv>
 
    <refsect1>
        <title>Description</title>
        <para><command>mosquitto_rr</command> is an MQTT version 5/3.1.1
            client that can be used to publish a request message and wait for a
            response. When using MQTT v5, which is the default,
            <command>mosquitto_rr</command> will use the Request-Response
            feature.</para>
    </refsect1>
 
    <refsect1>
        <title>Encrypted Connections</title>
        <para><command>mosquitto_rr</command> supports TLS encrypted
            connections. It is strongly recommended that you use an encrypted
            connection for anything more than the most basic setup.</para>
        <para>To enable TLS connections when using x509 certificates, one of
            either <option>--cafile</option> or <option>--capath</option> must
            be provided as an option.</para>
        <para>To enable TLS connections when using TLS-PSK, you must use the
            <option>--psk</option> and the <option>--psk-identity</option>
            options.</para>
    </refsect1>
 
    <refsect1>
        <title>Options</title>
        <para>The options below may be given on the command line, but may also
            be placed in a config file located at
            <option>$XDG_CONFIG_HOME/mosquitto_rr</option> or
            <option>$HOME/.config/mosquitto_rr</option> with one pair of
            <option>-option <replaceable>value</replaceable></option>
            per line. The values in the config file will be used as defaults
            and can be overridden by using the command line. The exceptions to
            this is <option>-t</option>, which if given in the config file will
            not be overridden. Note also that currently some options cannot be
            negated, e.g. <option>-S</option>. Config file lines that have a
            <option>#</option> as the first character are treated as comments
            and not processed any further.</para>
        <variablelist>
            <varlistentry>
                <term><option>-A</option></term>
                <listitem>
                    <para>Bind the outgoing connection to a local ip
                        address/hostname. Use this argument if you need to
                        restrict network communication to a particular
                        interface.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>-c</option></term>
                <term><option>--disable-clean-session</option></term>
                <listitem>
                    <para>Disable the 'clean session' flag. This means that all
                    of the subscriptions for the client will be maintained
                    after it disconnects, along with subsequent QoS 1 and QoS 2
                    messages that arrive. When the client reconnects, it will
                    receive all of the queued messages.</para>
                    <para>If using this option, the client id must be set
                        manually with <option>--id</option></para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>--cafile</option></term>
                <listitem>
                    <para>Define the path to a file containing PEM encoded CA
                        certificates that are trusted. Used to enable SSL
                        communication.</para>
                    <para>See also <option>--capath</option></para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>--capath</option></term>
                <listitem>
                    <para>Define the path to a directory containing PEM encoded CA
                        certificates that are trusted. Used to enable SSL
                        communication.</para>
                    <para>For <option>--capath</option> to work correctly, the
                        certificate files must have ".crt" as the file ending
                        and you must run "openssl rehash &lt;path to capath&gt;" each
                        time you add/remove a certificate.</para>
                    <para>See also <option>--cafile</option></para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>--cert</option></term>
                <listitem>
                    <para>Define the path to a file containing a PEM encoded
                        certificate for this client, if required by the
                        server.</para>
                    <para>See also <option>--key</option>.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>--ciphers</option></term>
                <listitem>
                    <para>An openssl compatible list of TLS ciphers to support
                        in the client. See
                        <citerefentry><refentrytitle>ciphers</refentrytitle><manvolnum>1</manvolnum></citerefentry>
                        for more information.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>-d</option></term>
                <term><option>--debug</option></term>
                <listitem>
                    <para>Enable debug messages.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>-D</option></term>
                <term><option>--property</option></term>
                <listitem>
                    <para>Use an MQTT v5 property with this publish. If you use
                        this option, the client will be set to be an MQTT v5
                        client. This option has two forms:</para>
                    <para><option>-D command identifier value</option></para>
                    <para><option>-D command identifier name value</option></para>
                    <para><option>command</option> is the MQTT command/packet
                        identifier and can be one of CONNECT, PUBACK, PUBREC,
                        PUBCOMP, SUBSCRIBE, UNSUBSCRIBE, DISCONNECT, AUTH, or
                        WILL. The properties available for each command are
                        listed in the Properties section.</para>
 
                    <para><option>identifier</option> is the name of the
                        property to add. This is as described in the
                        specification, but with '-' as a word separator. For
                        example:
                        <option>payload-format-indicator</option>. More details
                        are in the <link linkend='properties'>Properties</link>
                        section.</para>
 
                    <para><option>value</option> is the value of the property
                        to add, with a data type that is property
                        specific.</para>
 
                    <para><option>name</option> is only used for the
                        <option>user-property</option> property as the first of
                        the two strings in the string pair. In that case,
                        <option>value</option> is the second of the strings in
                        the pair.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>-f</option></term>
                <term><option>--file</option></term>
                <listitem>
                    <para>Send the contents of a file as the request message.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>-F</option></term>
                <listitem>
                    <para>Specify output printing format. This option allows
                        you to choose what information from each message is
                        printed to the screen. See the <link
                            linkend='outputformat'>Output Format</link> section
                        below for full details.</para>
                    <para>This option overrides the <option>-v</option> option,
                        but does not override the <option>-N</option>
                        option.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>--help</option></term>
                <listitem>
                    <para>Display usage information.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>-h</option></term>
                <term><option>--host</option></term>
                <listitem>
                    <para>Specify the host to connect to. Defaults to localhost.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>-i</option></term>
                <term><option>--id</option></term>
                <listitem>
                    <para>The id to use for this client. If not given, defaults
                    to mosquitto_rr_ appended with the process id of the
                    client. Cannot be used at the same time as the
                    <option>--id-prefix</option> argument.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>-I</option></term>
                <term><option>--id-prefix</option></term>
                <listitem>
                    <para>Provide a prefix that the client id will be built
                    from by appending the process id of the client. This is
                    useful where the broker is using the clientid_prefixes
                    option. Cannot be used at the same time as the
                    <option>--id</option> argument.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>--insecure</option></term>
                <listitem>
                    <para>When using certificate based encryption, this option
                        disables verification of the server hostname in the
                        server certificate. This can be useful when testing
                        initial server configurations but makes it possible for
                        a malicious third party to impersonate your server
                        through DNS spoofing, for example. Use this option in
                        testing <emphasis>only</emphasis>. If you need to
                        resort to using this option in a production
                        environment, your setup is at fault and there is no
                        point using encryption.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>-k</option></term>
                <term><option>--keepalive</option></term>
                <listitem>
                    <para>The number of seconds between sending PING commands
                    to the broker for the purposes of informing it we are still
                    connected and functioning. Defaults to 60 seconds.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>--key</option></term>
                <listitem>
                    <para>Define the path to a file containing a PEM encoded
                        private key for this client, if required by the
                        server.</para>
                    <para>See also <option>--cert</option>.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>--keyform</option></term>
                <listitem>
                    <para>Specifies the type of private key in use when making
                        TLS connections.. This can be "pem" or "engine". This
                        parameter is useful when a TPM module is being used and
                        the private key has been created with it. Defaults to
                        "pem", which means normal private key files are
                        used.</para>
                    <para>See also <option>--tls-engine</option>.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>-L</option></term>
                <term><option>--url</option></term>
                <listitem>
                    <para>Specify specify user, password, hostname, port and
                        topic at once as a URL.  The URL must be in the form:
                        mqtt(s)://[username[:password]@]host[:port]/topic</para>
                    <para>If the scheme is mqtt:// then the port defaults to
                        1883. If the scheme is mqtts:// then the port defaults
                        to 8883.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>-m</option></term>
                <term><option>--message</option></term>
                <listitem>
                    <para>Send a single request message from the command line.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>-N</option></term>
                <listitem>
                    <para>Do not append an end of line character to the payload
                        when printing. This allows streaming of payload data
                        from multiple messages directly to another application
                        unmodified. Only really makes sense when not using
                        <option>-v</option>.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>-n</option></term>
                <term><option>--null-message</option></term>
                <listitem>
                    <para>Send a null (zero length) request message.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>-p</option></term>
                <term><option>--port</option></term>
                <listitem>
                    <para>Connect to the port specified. If not given, the
                        default of 1883 for plain MQTT or 8883 for MQTT over
                        TLS will be used.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>-P</option></term>
                <term><option>--pw</option></term>
                <listitem>
                    <para>Provide a password to be used for authenticating with
                        the broker. Using this argument without also specifying
                        a username is invalid when using MQTT v3.1 or v3.1.1.
                        See also the <option>--username</option> option.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>--proxy</option></term>
                <listitem>
                    <para>Specify a SOCKS5 proxy to connect through. "None" and
                        "username" authentication types are supported. The
                        <option>socks-url</option> must be of the form
                        <option>socks5h://[username[:password]@]host[:port]</option>.
                        The protocol prefix <option>socks5h</option> means that
                        hostnames are resolved by the proxy. The symbols %25,
                        %3A and %40 are URL decoded into %, : and @
                        respectively, if present in the username or
                        password.</para>
                    <para>If username is not given, then no authentication is
                        attempted. If the port is not given, then the default
                        of 1080 is used.</para>
                    <para>More SOCKS versions may be available in the future,
                        depending on demand, and will use different protocol
                        prefixes as described in <citerefentry>
                            <refentrytitle>curl</refentrytitle>
                            <manvolnum>1</manvolnum> </citerefentry>.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>--psk</option></term>
                <listitem>
                    <para>Provide the hexadecimal (no leading 0x)
                        pre-shared-key matching the one used on the broker to
                        use TLS-PSK encryption support.
                        <option>--psk-identity</option> must also be provided
                        to enable TLS-PSK.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>--psk-identity</option></term>
                <listitem>
                    <para>The client identity to use with TLS-PSK support. This
                        may be used instead of a username if the broker is
                        configured to do so.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>-q</option></term>
                <term><option>--qos</option></term>
                <listitem>
                    <para>Specify the quality of service desired for the
                    incoming messages, from 0, 1 and 2. Defaults to 0. See
                    <citerefentry><refentrytitle>mqtt</refentrytitle><manvolnum>7</manvolnum></citerefentry>
                    for more information on QoS.</para>
                    <para>The QoS is identical for all topics subscribed to in
                    a single instance of mosquitto_rr.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>--quiet</option></term>
                <listitem>
                    <para>If this argument is given, no runtime errors will be
                    printed. This excludes any error messages given in case of
                    invalid user input (e.g. using <option>--port</option> without a
                    port).</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>-R</option></term>
                <listitem>
                    <para>If this argument is given, messages that are received
                        that have the retain bit set will not be printed.
                        Messages with retain set are "stale", in that it is not
                        known when they were originally published. When
                        subscribing to a wildcard topic there may be a large
                        number of retained messages. This argument suppresses
                        their display.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>-S</option></term>
                <listitem>
                    <para>Use SRV lookups to determine which host to connect
                        to. Performs lookups to
                        <option>_mqtt._tcp.&lt;host&gt;</option> when used in
                        conjunction with <option>-h</option>, otherwise uses
                        <option>_mqtt._tcp.&lt;local dns
                            domain&gt;</option>.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>-s</option></term>
                <term><option>--stdin-file</option></term>
                <listitem>
                    <para>Send a request message read from stdin, sending the entire content as a single message.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>-t</option></term>
                <term><option>--topic</option></term>
                <listitem>
                    <para>The MQTT topic to subscribe to, where responses will
                        be waited for. See
                    <citerefentry><refentrytitle>mqtt</refentrytitle><manvolnum>7</manvolnum></citerefentry>
                    for more information on MQTT topics.</para>
                    <para>This option may be repeated to subscribe to multiple topics.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>--tls-alpn</option></term>
                <listitem>
                    <para>Provide a protocol to use when connecting to a broker
                        that has multiple protocols available on a single port,
                        e.g. MQTT and WebSockets.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>--tls-engine</option></term>
                <listitem>
                    <para>A valid openssl engine id. These can be listed with
                        openssl engine command.</para>
                    <para>See also <option>--keyform</option>.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>--tls-engine-kpass-sha1</option></term>
                <listitem>
                    <para>SHA1 of the private key password when using an TLS
                        engine.  Some TLS engines such as the TPM engine may
                        require the use of a password in order to be accessed.
                        This option allows a hex encoded SHA1 hash of the
                        password to the engine directly, instead of the user
                        being prompted for the password.</para>
                    <para>See also <option>--tls-engine</option>.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>--tls-version</option></term>
                <listitem>
                    <para>Choose which TLS protocol version to use when
                        communicating with the broker. Valid options are
                        <option>tlsv1.3</option>, <option>tlsv1.2</option> and
                        <option>tlsv1.1</option>. The default value is
                        <option>tlsv1.2</option>. Must match the protocol
                        version used by the broker.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>-u</option></term>
                <term><option>--username</option></term>
                <listitem>
                    <para>Provide a username to be used for authenticating with
                        the broker. See also the <option>--pw</option>
                        argument.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>-v</option></term>
                <term><option>--verbose</option></term>
                <listitem>
                    <para>Print received messages verbosely. With this
                    argument, messages will be printed as "topic payload". When
                    this argument is not given, the messages are printed as
                    "payload".</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>-V</option></term>
                <term><option>--protocol-version</option></term>
                <listitem>
                    <para>Specify which version of the MQTT protocol should be
                        used when connecting to the rmeote broker. Can be
                        <option>5</option>, <option>311</option>,
                        <option>31</option>, or the more verbose
                        <option>mqttv5</option>, <option>mqttv311</option>, or
                        <option>mqttv31</option>.
                        Defaults to <option>311</option>.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>--will-payload</option></term>
                <listitem>
                    <para>Specify a message that will be stored by the broker
                    and sent out if this client disconnects unexpectedly. This
                    must be used in conjunction with <option>--will-topic</option>.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>--will-qos</option></term>
                <listitem>
                    <para>The QoS to use for the Will. Defaults to 0. This must
                    be used in conjunction with <option>--will-topic</option>.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>--will-retain</option></term>
                <listitem>
                    <para>If given, if the client disconnects unexpectedly the
                    message sent out will be treated as a retained message.
                    This must be used in conjunction with <option>--will-topic</option>.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><option>--will-topic</option></term>
                <listitem>
                    <para>The topic on which to send a Will, in the event that
                    the client disconnects unexpectedly.</para>
                </listitem>
            </varlistentry>
        </variablelist>
    </refsect1>
 
    <refsect1 id='outputformat'>
        <title>Output format</title>
        <para>There are three ways of formatting the output from mosquitto_rr.
            In all cases a new-line character is appended for each message
            received unless the <option>-N</option> argument is passed to
            mosquitto_rr.</para>
        <para>Payload-only is the default output format and will
            print the payload exactly as it is received.</para>
        <para>Verbose mode is activated with <option>-v</option> and prints the
            message topic and the payload, separated by a space.</para>
        <para>The final option is formatted output, which allows the user to
            define a custom output format.  The behaviour is controlled with
            the <option>-F format-string</option> option. The format string is
            a free text string where interpreted sequences are replaced by
            different parameters. The available interpreted sequences are
            described below.</para>
        <para>Three characters are used to start an interpreted sequence:
            <option>%</option>, <option>@</option> and <option>\</option>.
            Sequences starting with <option>%</option> are either parameters
            related to the MQTT message being printed, or are helper sequences
            to avoid the need to type long date format strings for example.
            Sequences starting with <option>@</option> are passed to the
            <citerefentry><refentrytitle>strftime</refentrytitle><manvolnum>3</manvolnum></citerefentry>
            function (with the @ replaced with a % - note that only the
            character immediately after the @ is passed to strftime). This
            allows the construction of a wide variety of time based outputs.
            The output options for strftime vary from platform to platform, so
            please check what is available for your platform. mosquitto_rr
            does provide one extension to strftime which is
            <option>@N</option>, which can be used to obtain the number of
            nanoseconds passed in the current second. The resolution of this
            option varies depending on the platform. The final sequence
            character is <option>\</option>, which is used to input some
            characters that would otherwise be difficult to enter.</para>
 
        <refsect2>
            <title>MQTT related parameters</title>
            <itemizedlist mark="circle">
                <listitem><para><option>%%</option> a literal %.</para></listitem>
                <listitem><para><option>%l</option> the length of the payload in bytes.</para></listitem>
                <listitem><para><option>%m</option> the message id (only relevant for messages with QoS>0).</para></listitem>
                <listitem><para><option>%p</option> the payload raw bytes (may produce non-printable characters depending on the payload).</para></listitem>
                <listitem><para><option>%q</option> the message QoS.</para></listitem>
                <listitem><para><option>%r</option> the retained flag for the message.</para></listitem>
                <listitem><para><option>%t</option> the message topic.</para></listitem>
                <listitem><para><option>%x</option> the payload with each byte as a hexadecimal number (lower case).</para></listitem>
                <listitem><para><option>%X</option> the payload with each byte as a hexadecimal number (upper case).</para></listitem>
            </itemizedlist>
        </refsect2>
 
        <refsect2>
            <title>Helpers</title>
            <itemizedlist mark="circle">
                <listitem><para><option>%I</option> ISO-8601 format date and time, e.g. 2016-08-10T09:47:38+0100</para></listitem>
                <listitem><para><option>%j</option> JSON output of message
                        parameters and timestamp, with a quoted and escaped
                        payload. For example
                        <code>{"tst":1470825369,"topic":"greeting","qos":0,"retain":0,"payload":"hello
                            world"}</code></para></listitem>
                <listitem><para><option>%J</option> JSON output of message
                        parameters and timestamp, with a non-quoted and
                        non-escaped payload - this means the payload must
                        itself be valid JSON. For example:
                        <code>{"tst":1470825369,"topic":"foo","qos":0,"retain":0,"payload":{"temperature":27.0,"humidity":57}}</code>.</para></listitem>
                <listitem><para><option>%I</option> ISO-8601 format date and time, e.g. 2016-08-10T09:47:38+0100</para></listitem>
                <listitem><para><option>%U</option> Unix timestamp with nanoseconds, e.g. 1470818943.786368637</para></listitem>
            </itemizedlist>
        </refsect2>
 
        <refsect2>
            <title>Time related parameters</title>
            <itemizedlist mark="circle">
                <listitem><para><option>@@</option> a literal @.</para></listitem>
                <listitem><para><option>@X</option> pass the character represented
                        by <option>X</option> to the strftime function as
                        <option>%X</option>. The options supported are platform
                        dependent.</para></listitem>
                <listitem><para><option>@N</option> the number of nanoseconds that
                        have passed in the current second, with varying timing
                        resolution depending on platform.</para></listitem>
            </itemizedlist>
        </refsect2>
 
        <refsect2>
            <title>Escape characters</title>
            <itemizedlist mark="circle">
                <listitem><para><option>\\</option> a literal \.</para></listitem>
                <listitem><para><option>\0</option> a null character. Can be used
                        to separate different parameters that may contain spaces
                        (e.g. topic, payload) so that processing with tools such as
                        <citerefentry><refentrytitle>xargs</refentrytitle><manvolnum>1</manvolnum></citerefentry>
                        is easier.</para></listitem>
                <listitem><para><option>\a</option> alert/bell.</para></listitem>
                <listitem><para><option>\e</option> the escape sequence, which can
                        be used with ANSI colour codes to provide coloured output
                        for example.</para></listitem>
                <listitem><para><option>\n</option> end of line.</para></listitem>
                <listitem><para><option>\r</option> carriage return.</para></listitem>
                <listitem><para><option>\t</option> horizontal tab.</para></listitem>
                <listitem><para><option>\v</option> vertical tab.</para></listitem>
            </itemizedlist>
        </refsect2>
    </refsect1>
 
    <refsect1>
        <title>Wills</title>
        <para>mosquitto_rr can register a message with the broker that will be
        sent out if it disconnects unexpectedly. See
        <citerefentry><refentrytitle>mqtt</refentrytitle><manvolnum>7</manvolnum></citerefentry>
        for more information.</para>
        <para>The minimum requirement for this is to use <option>--will-topic</option> to
        specify which topic the will should be sent out on. This will result in
        a non-retained, zero length message with QoS 0.</para>
        <para>Use the <option>--will-retain</option>, <option>--will-payload</option> and <option>--will-qos</option> arguments to
        modify the other will parameters.</para>
    </refsect1>
 
    <refsect1 id='properties'>
        <title>Properties</title>
        <para>The <option>-D</option> / <option>--property</option> option
            allows adding properties to different stages of the mosquitto_rr
            run. The properties supported for each command are as
            follows:</para>
 
        <refsect2>
            <title>Connect</title>
            <itemizedlist>
                <listitem><para><option>authentication-data</option> (binary data - note treated as a string in mosquitto_rr)</para></listitem>
                <listitem><para><option>authentication-method</option> (UTF-8 string pair)</para></listitem>
                <listitem><para><option>maximum-packet-size</option> (32-bit unsigned integer)</para></listitem>
                <listitem><para><option>receive-maximum</option> (16-bit unsigned integer)</para></listitem>
                <listitem><para><option>request-problem-information</option> (8-bit unsigned integer)</para></listitem>
                <listitem><para><option>request-response-information</option> (8-bit unsigned integer)</para></listitem>
                <listitem><para><option>session-expiry-interval</option> (32-bit unsigned integer)</para></listitem>
                <listitem><para><option>topic-alias-maximum</option> (16-bit unsigned integer)</para></listitem>
                <listitem><para><option>user-property</option> (UTF-8 string pair)</para></listitem>
            </itemizedlist>
        </refsect2>
 
        <refsect2>
            <title>Publish</title>
            <itemizedlist>
                <listitem><para><option>content-type</option> (UTF-8 string)</para></listitem>
                <listitem><para><option>correlation-data</option> (binary data - note treated as a string in mosquitto_rr)</para></listitem>
                <listitem><para><option>message-expiry-interval</option> (32-bit unsigned integer)</para></listitem>
                <listitem><para><option>payload-format-indicator</option> (8-bit unsigned integer)</para></listitem>
                <listitem><para><option>response-topic</option> (UTF-8 string)</para></listitem>
                <listitem><para><option>topic-alias</option> (16-bit unsigned integer)</para></listitem>
                <listitem><para><option>user-property</option> (UTF-8 string pair)</para></listitem>
            </itemizedlist>
        </refsect2>
 
        <refsect2>
            <title>Subscribe</title>
            <itemizedlist>
                <listitem><para><option>user-property</option> (UTF-8 string pair)</para></listitem>
            </itemizedlist>
        </refsect2>
 
        <refsect2>
            <title>Unsubscribe</title>
            <itemizedlist>
                <listitem><para><option>user-property</option> (UTF-8 string pair)</para></listitem>
            </itemizedlist>
        </refsect2>
 
        <refsect2>
            <title>Disconnect</title>
            <itemizedlist>
                <listitem><para><option>session-expiry-interval</option> (32-bit unsigned integer)</para></listitem>
                <listitem><para><option>user-property</option> (UTF-8 string pair)</para></listitem>
            </itemizedlist>
        </refsect2>
 
        <refsect2>
            <title>Will properties</title>
            <itemizedlist>
                <listitem><para><option>content-type</option> (UTF-8 string)</para></listitem>
                <listitem><para><option>correlation-data</option> (binary data - note treated as a string in mosquitto_pub)</para></listitem>
                <listitem><para><option>message-expiry-interval</option> (32-bit unsigned integer)</para></listitem>
                <listitem><para><option>payload-format-indicator</option> (8-bit unsigned integer)</para></listitem>
                <listitem><para><option>response-topic</option> (UTF-8 string)</para></listitem>
                <listitem><para><option>user-property</option> (UTF-8 string pair)</para></listitem>
                <listitem><para><option>will-delay-interval</option> (32-bit unsigned integer)</para></listitem>
            </itemizedlist>
        </refsect2>
    </refsect1>
 
    <refsect1>
        <title>Files</title>
        <variablelist>
            <varlistentry>
                <term><filename>$XDG_CONFIG_HOME/mosquitto_rr</filename></term>
                <term><filename>$HOME/.config/mosquitto_rr</filename></term>
                <listitem>
                    <para>Configuration file for default options.</para>
                </listitem>
            </varlistentry>
        </variablelist>
    </refsect1>
 
    <refsect1>
        <title>Bugs</title>
        <para><command>mosquitto</command> bug information can be found at
            <ulink url="https://github.com/eclipse/mosquitto/issues"/></para>
    </refsect1>
 
    <refsect1>
        <title>See Also</title>
        <simplelist type="inline">
            <member>
                <citerefentry>
                    <refentrytitle><link xlink:href="mqtt-7.html">mqtt</link></refentrytitle>
                    <manvolnum>7</manvolnum>
                </citerefentry>
            </member>
            <member>
                <citerefentry>
                    <refentrytitle><link xlink:href="mosquitto_pub-1.html">mosquitto_pub</link></refentrytitle>
                    <manvolnum>1</manvolnum>
                </citerefentry>
            </member>
            <member>
                <citerefentry>
                    <refentrytitle><link xlink:href="mosquitto_sub-1.html">mosquitto_sub</link></refentrytitle>
                    <manvolnum>1</manvolnum>
                </citerefentry>
            </member>
            <member>
                <citerefentry>
                    <refentrytitle><link xlink:href="mosquitto-8.html">mosquitto</link></refentrytitle>
                    <manvolnum>8</manvolnum>
                </citerefentry>
            </member>
            <member>
                <citerefentry>
                    <refentrytitle><link xlink:href="libmosquitto-3.html">libmosquitto</link></refentrytitle>
                    <manvolnum>3</manvolnum>
                </citerefentry>
            </member>
            <member>
                <citerefentry>
                    <refentrytitle><link xlink:href="mosquitto-tls-7.html">mosquitto-tls</link></refentrytitle>
                    <manvolnum>7</manvolnum>
                </citerefentry>
            </member>
        </simplelist>
    </refsect1>
 
    <refsect1>
        <title>Author</title>
        <para>Roger Light <email>roger@atchoo.org</email></para>
    </refsect1>
</refentry>