hbmqtt_sub is a command line MQTT client that subscribes to some topics and output data received from messages published.


hbmqtt_sub usage :

hbmqtt_sub --version
hbmqtt_sub (-h | --help)
hbmqtt_sub --url BROKER_URL -t TOPIC... [-n COUNT] [-c CONFIG_FILE] [-i CLIENT_ID] [-q | --qos QOS] [-d]
           [-k KEEP_ALIVE] [--clean-session] [--ca-file CAFILE] [--ca-path CAPATH] [--ca-data CADATA]
           [ --will-topic WILL_TOPIC [--will-message WILL_MESSAGE] [--will-qos WILL_QOS] [--will-retain] ]

Note that for simplicity, hbmqtt_sub uses mostly the same argument syntax as mosquitto_sub.


--version HBMQTT version information
-h, --help Display hbmqtt_sub usage help
-c Set the YAML configuration file to read and pass to the client runtime.
-d Enable debugging informations.
--ca-file Define the path to a file containing PEM encoded CA certificates that are trusted. Used to enable SSL communication.
--ca-path Define the path to a directory containing PEM encoded CA certificates that are trusted. Used to enable SSL communication.
--ca-data Set the PEM encoded CA certificates that are trusted. Used to enable SSL communication.
 If given, set the CONNECT clean session flag to True.
-i The id to use for this client. If not given, defaults to hbmqtt_sub/ appended with the process id and the hostname of the client.
-k Set the CONNECT keep alive timeout.
-n Number of messages to read before ending. Read forever if not given.
-q, --qos Specify the quality of service to use for receiving messages. This QoS is sent in the subscribe request.
-t Topic filters to subcribe.
--url Broker connection URL, conforming to MQTT URL scheme.
--will-topic The topic on which to send a Will, in the event that the client disconnects unexpectedly.
--will-message 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.


If -c argument is given, hbmqtt_sub will read specific MQTT settings for the given configuration file. This file must be a valid YAML file which may contains the following configuration elements :

  • keep_alive : Keep-alive timeout sent to the broker. Defaults to 10 seconds.
  • ping_delay : Auto-ping delay before keep-alive timeout. Defaults to 1. Setting to 0 will disable to 0 and may lead to broker disconnection.
  • default_qos : Default QoS for messages published. Defaults to 0.
  • default_retain : Default retain value to messages published. Defaults to false.
  • auto_reconnect : Enable or disable auto-reconnect if connectection with the broker is interrupted. Defaults to false.
  • reconnect_retries : Maximum reconnection retries. Defaults to 2.
  • reconnect_max_interval : Maximum interval between 2 connection retry. Defaults to 10.


Examples below are adapted from mosquitto_sub documentation.

Subscribe with QoS 0 to all messages plublish under $SYS/:

hbmqtt_sub --url mqtt://localhost -t '$SYS/#' -q 0

Subscribe to 10 messages with QoS 2 from /#:

hbmqtt_sub --url mqtt://localhost -t /# -q 2 -n 10