mosquitto_sub1Mosquitto ProjectCommandsmosquitto_suban MQTT version 3.1 client for subscribing to topicsmosquitto_subbind_addressmsg counthostnameclient_idclient id prefixkeepalive timeport numbermessage QoSusernamepasswordtopicpayloadqosfiledirfilefileversionhex-keyidentityversionsocks-urlprotocol-versionfilter-outmessage-topicmosquitto_subDescriptionmosquitto_sub is a simple MQTT version 3.1
client that will subscribe to a topic and print the messages that it
receives.OptionsThe options below may be given on the command line, but may also
be placed in a config file located at
or
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 and , which if
given in the config file will not be overridden. Note also that
currently some options cannot be negated, e.g.
. 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, it is recommended that the
client id is set manually with Define the path to a file containing PEM encoded CA
certificates that are trusted. Used to enable SSL
communication.See also Define the path to a directory containing PEM encoded CA
certificates that are trusted. Used to enable SSL
communication.For to work correctly, the
certificate files must have ".crt" as the file ending
and you must run "c_rehash <path to capath>" each
time you add/remove a certificate.See also Define the path to a file containing a PEM encoded
certificate for this client, if required by the
server.See also .An openssl compatible list of TLS ciphers to support
in the client. See
ciphers1
for more information.Disconnect and exit the program immediately after
the given count of messages have been received. This
may be useful in shell scripts where on a single status
value is required, for example.Combine with to print only the
first set of fresh messages (i.e. that does not have
the retained flag set), or with to
filter which topics are processed.Enable debug messages.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_sub_ appended with the process id of the
client. Cannot be used at the same time as the
argument.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
argument.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.See also .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
.Connect to the port specified instead of the default 1883.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.Specify a SOCKS5 proxy to connect through. "None" and
"username" authentication types are supported. The
must be of the form
.
The protocol prefix 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.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 curl1.Provide the hexadecimal (no leading 0x)
pre-shared-key matching the one used on the broker to
use TLS-PSK encryption support.
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 desired for the
incoming messages, from 0, 1 and 2. Defaults to 0. See
mqtt7
for more information on QoS.The QoS is identical for all topics subscribed to in
a single instance of mosquitto_sub.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 without a
port).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.Use SRV lookups to determine which host to connect
to. Performs lookups to
when used in
conjunction with , otherwise uses
.The MQTT topic to subscribe to. See
mqtt7
for more information on MQTT topics.This option may be repeated to subscribe to multiple topics.Suppress printing of topics that match the filter.
This allows subscribing to a wildcard topic and only
printing a partial set of the wildcard
hierarchy.For example, subscribe to the BBC tree, but suppress output from Radio 3:mosquitto_sub -t
bbc/# -T
bbc/radio3This option may be repeated to filter out multiple
topics or topic trees.Choose which TLS protocol version to use when
communicating with the broker. Valid options are
, and
. The default value is
. If the installed version of
openssl is too old, only will be
available. Must match the protocol version used by the
broker.Provide a username to be used for authenticating with
the broker. This requires a broker that supports MQTT v3.1.
See also the argument.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".Specify which version of the MQTT protocol should be
used when connecting to the rmeote broker. Can be
or .
Defaults to .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.Willsmosquitto_sub can register a message with the broker that will be
sent out if it disconnects unexpectedly. See
mqtt7
for more information.The minimum requirement for this is to use to
specify which topic the will should be sent out on. This will result in
a non-retained, zero length message with QoS 0.Use the , and arguments to
modify the other will parameters.ExamplesNote that these really are examples - the subscriptions will work
if you run them as shown, but there must be something publishing
messages on those topics for you to receive anything.Subscribe to temperature information on localhost with QoS 1:mosquitto_sub -t sensors/temperature -q 1Subscribe to hard drive temperature updates on multiple
machines/hard drives. This expects each machine to be publishing its
hard drive temperature to
sensors/machines/HOSTNAME/temperature/HD_NAME.mosquitto_sub -t sensors/machines/+/temperature/+Subscribe to all broker status messages:mosquitto_sub -v-t \$SYS/#Files$XDG_CONFIG_HOME/mosquitto_sub$HOME/.config/mosquitto_subConfiguration file for default options.Bugsmosquitto bug information can be found at
https://github.com/eclipse/mosquitto/issuesSee Alsomqtt7mosquitto_pub1mosquitto8libmosquitto3mosquitto-tls7AuthorRoger Light roger@atchoo.org