mosquitto_pub — an MQTT version 3.1.1/3.1 client for publishing simple messages
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client id prefix] [
keepalive time] [
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mosquitto_pub is a simple MQTT version 3.1.1 client that will publish a single message on a topic and exit.
mosquitto_pub supports TLS encrypted connections. It is strongly recommended that you use an encrypted connection for anything more than the most basic setup.
To enable TLS connections when using x509 certificates, one of
be provided as an option.
To enable TLS connections when using TLS-PSK, you must use the
--psk and the
The options below may be given on the command line, but may also
be placed in a config file located at
$HOME/.config/mosquitto_sub with one pair of
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 are the message type options, of which only one can be
specified. Note also that currently some options cannot be negated,
-S. Config file lines that have a
# as the first character are treated as comments
and not processed any further.
Bind the outgoing connection to a local ip address/hostname. Use this argument if you need to restrict network communication to a particular interface.
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.
If using this option, the client id must be set
Define the path to a file containing PEM encoded CA certificates that are trusted. Used to enable SSL communication.
Define the path to a directory containing PEM encoded CA certificates that are trusted. Used to enable SSL communication.
--capath to work correctly, the
certificate files must have ".crt" as the file ending
and you must run "openssl rehash <path to capath>" each
time you add/remove a certificate.
Define the path to a file containing a PEM encoded certificate for this client, if required by the server.
An openssl compatible list of TLS ciphers to support in the client. See ciphers(1) for more information.
Enable debug messages.
Send the contents of a file as the message.
Display usage information.
Specify the host to connect to. Defaults to localhost.
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
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
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 only. 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.
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.
Define the path to a file containing a PEM encoded private key for this client, if required by the server.
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
If the scheme is mqtt:// then the port defaults to 1883. If the scheme is mqtts:// then the port defaults to 8883.
Send messages read from stdin, splitting separate lines into separate messages. Note that blank lines won't be sent.
Send a single message from the command line.
Send a null (zero length) message.
Connect to the port specified. If not given, the default of 1883 for plain MQTT or 8883 for MQTT over TLS will be used.
Provide a password to be used for authenticating with
the broker. Using this argument without also specifying
a username is invalid. See also the
Specify a SOCKS5 proxy to connect through. "None" and
"username" authentication types are supported. The
socks-url must be of the form
The protocol prefix
socks5h 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
If username is not given, then no authentication is attempted. If the port is not given, then the default of 1080 is used.
More SOCKS versions may be available in the future, depending on demand, and will use different protocol prefixes as described in curl(1).
Provide the hexadecimal (no leading 0x)
pre-shared-key matching the one used on the broker to
use TLS-PSK encryption support.
--psk-identity must also be provided
to enable TLS-PSK.
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.
Specify the quality of service to use for the message, from 0, 1 and 2. Defaults to 0.
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
--port without a
If retain is given, the message will be retained as a "last known good" value on the broker. See mqtt(7) for more information.
Send a message read from stdin, sending the entire content as a single message.
Use SRV lookups to determine which host to connect
to. Performs lookups to
_mqtt._tcp.<host> when used in
-h, otherwise uses
The MQTT topic on which to publish the message. See mqtt(7) for more information on MQTT topics.
Choose which TLS protocol version to use when
communicating with the broker. Valid options are
tlsv1. The default value is
tlsv1.2. If the installed version of
openssl is too old, only
tlsv1 will be
available. Must match the protocol version used by the
Provide a username to be used for authenticating with
the broker. See also the
Specify which version of the MQTT protocol should be
used when connecting to the rmeote broker. Can be
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
The QoS to use for the Will. Defaults to 0. This must
be used in conjunction with
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
The topic on which to send a Will, in the event that the client disconnects unexpectedly.
mosquitto_sub can register a message with the broker that will be sent out if it disconnects unexpectedly. See mqtt(7) for more information.
The minimum requirement for this is to use
specify which topic the will should be sent out on. This will result in
a non-retained, zero length message with QoS 0.
arguments to modify the other will parameters.
Publish temperature information to localhost with QoS 1:
Publish timestamp and temperature information to a remote host on a non-standard port and QoS 0:
Publish light switch status. Message is set to retained because there may be a long period of time between light switch events:
Send the contents of a file in two ways:
-s < ./data
Send parsed electricity usage data from a Current Cost meter, reading from stdin with one line/reading as one message:
read_cc128.pl | mosquitto_pub
Configuration file for default options.
mosquitto bug information can be found at https://github.com/eclipse/mosquitto/issues