MOSQUITTO_SUB(1) Commands MOSQUITTO_SUB(1)NAMEmosquitto_sub - an MQTT version 3.1 client for subscribing to topics
SYNOPSISmosquitto_sub [-A bind_address] [-c] [-d] [-h hostname] [-i client_id]
[-I client id prefix] [-k keepalive time]
[-p port number] [-q message QoS] [-R] [-S] [-N]
[--quiet] [-v] [[-u username] [-P password]]
[--will-topic topic [--will-payload payload] [--will-qos qos] [--will-retain]]
[[{--cafile file | --capath dir} [--cert file] [--key file] [--tls-version version] [--insecure]]
|
[--psk hex-key --psk-identity identity [--tls-version version]]]
[-T filter-out...] -t message-topic...
mosquitto_sub [--help]
DESCRIPTIONmosquitto_sub is a simple MQTT version 3.1 client that will subscribe
to a topic and print the messages that it receives.
OPTIONS-A
Bind the outgoing connection to a local ip address/hostname. Use
this argument if you need to restrict network communication to a
particular interface.
-c, --disable-clean-session
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 --id
--cafile
Define the path to a file containing PEM encoded CA certificates
that are trusted. Used to enable SSL communication.
See also --capath
--capath
Define the path to a directory containing PEM encoded CA
certificates that are trusted. Used to enable SSL communication.
For --capath 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 --cafile
--cert
Define the path to a file containing a PEM encoded certificate for
this client, if required by the server.
See also --key.
--ciphers
An openssl compatible list of TLS ciphers to support in the client.
See ciphers(1) for more information.
-d, --debug
Enable debug messages.
--help
Display usage information.
-h, --host
Specify the host to connect to. Defaults to localhost.
-i, --id
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 --id-prefix argument.
-I, --id-prefix
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 --id argument.
--insecure
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.
-k, --keepalive
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.
--key
Define the path to a file containing a PEM encoded private key for
this client, if required by the server.
See also --cert.
-N
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 -v.
-p, --port
Connect to the port specified instead of the default 1883.
-P, --pw
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
--username option.
--psk
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.
--psk-identity
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.
-q, --qos
Specify the quality of service desired for the incoming messages,
from 0, 1 and 2. Defaults to 0. See mqtt(7) for more information on
QoS.
The QoS is identical for all topics subscribed to in a single
instance of mosquitto_sub.
--quiet
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 port).
-R
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.
-S
Use SRV lookups to determine which host to connect to. Performs
lookups to _mqtt._tcp.<host> when used in conjunction with -h,
otherwise uses _mqtt._tcp.<local dns domain>.
-t, --topic
The MQTT topic to subscribe to. See mqtt(7) for more information on
MQTT topics.
This option may be repeated to subscribe to multiple topics.
-T, --filter-out
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/radio3
This option may be repeated to filter out multiple topics or topic
trees.
--tls-version
Choose which TLS protocol version to use when communicating with
the broker. Valid options are tlsv1.2, tlsv1.1 and 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 broker.
-u, --username
Provide a username to be used for authenticating with the broker.
This requires a broker that supports MQTT v3.1. See also the --pw
argument.
-v, --verbose
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".
--will-payload
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 --will-topic.
--will-qos
The QoS to use for the Will. Defaults to 0. This must be used in
conjunction with --will-topic.
--will-retain
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 --will-topic.
--will-topic
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 mqtt(7) for more information.
The minimum requirement for this is to use --will-topic 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 --will-retain, --will-payload and --will-qos arguments to
modify the other will parameters.
EXAMPLES
Note 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 1
Subscribe 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/#
BUGSmosquitto_sub bug information can be found at
http://launchpad.net/mosquitto
SEE ALSOmqtt(7), mosquitto_pub(1), mosquitto(8), libmosquitto(3), mosquitto-
tls(7)ACKNOWLEDGEMENTS
This product includes software developed by the OpenSSL Project for use
in the OpenSSL Toolkit. (http://www.openssl.org/)
This product includes cryptographic software written by Eric Young
(eay@cryptsoft.com)
This product includes software written by Tim Hudson
(tjh@cryptsoft.com)
AUTHOR
Roger Light <roger@atchoo.org>
Mosquitto Project 03/24/2014 MOSQUITTO_SUB(1)
