<para>Send the contents of a file as the message.</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_pub_ 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>--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>-l</option></term>
<term><option>--stdin-line</option></term>
<listitem>
<para>Send messages read from stdin, splitting separate lines into separate messages. Note that blank lines won't be sent.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-m</option></term>
<term><option>--message</option></term>
<listitem>
<para>Send a single message from the command line.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-n</option></term>
<term><option>--null-message</option></term>
<listitem>
<para>Send a null (zero length) message.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-p</option></term>
<term><option>--port</option></term>
<listitem>
<para>Connect to the port specified instead of the default 1883.</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. This requires a broker that supports
MQTT v3.1. See also the <option>--username</option> option.</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 to use for the message, from 0, 1 and 2. Defaults to 0.</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>
<term><option>--retain</option></term>
<listitem>
<para>If retain is given, the message will be retained as a "last known good" value on the broker. See <citerefentry><refentrytitle>mqtt</refentrytitle><manvolnum>7</manvolnum></citerefentry> for more information.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-s</option></term>
<term><option>--stdin-file</option></term>
<listitem>
<para>Send a message read from stdin, sending the entire content as a single message.</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.<host></option> when used in
conjunction with <option>-h</option>, otherwise uses
<option>_mqtt._tcp.<local dns
domain></option>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-t</option></term>
<term><option>--topic</option></term>
<listitem>
<para>The MQTT topic on which to publish the message. See <citerefentry><refentrytitle>mqtt</refentrytitle><manvolnum>7</manvolnum></citerefentry> for more information on MQTT topics.</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>tlsv1.2</option>, <option>tlsv1.1</option> and
<option>tlsv1</option>. The default value is
<option>tlsv1.2</option>. If the installed version of
openssl is too old, only <option>tlsv1</option> will be
available. 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. This requires a broker that supports MQTT v3.1.
See also the <option>--pw</option> argument.</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>
<title>Wills</title>
<para>mosquitto_sub can register a message with the broker that will be