Subscribe

Subscribes a client to one or more topics. If the Subscribe command is not called in Shell-Mode, it will block the console and write the received publishes to the console.

Simple Examples

Command	Explanation
`mqtt sub -t topic`	Subscribe to a topic with default settings and block the console.
`mqtt sub -t test1 -t test2`	Subscribe to the topics ‘test1’ and ‘test2’ with default settings and block the console.
`mqtt sub -t test -h localhost -p 1884`	Subscribe to topic ‘test’ at a broker with the address ‘localhost:1884’.

Synopsis

mqtt sub    -t <topics> [-t <topics>]... 
            [-q <qos>]... 
            [-of <receivedMessagesFile>] 
            [-b64]
            [-J]
            [-T]
            [-up <userProperties>]... 
            [-dsvl]
            [-h <host>] 
            [-p <port>]                                         
            [-V <version>] 
            [-i <identifier>] 
            [-ip <identifierPrefix>]
            [-k <keepAlive>]  
            [-se <sessionExpiryInterval>]
            [--[no-]cleanStart]      
            [-Cup <connectUserProperties>]...
            [-ws]
            [-ws:path <webSocketPath>] 
            [-u <user>] 
            [-pw [<password>]]
            [-pw:env [<environmentVariable>]]
            [-pw:file FILE]
            [--cert <clientCertificate>] 
            [--key <clientPrivateKey>]             
            [--cafile FILE]... 
            [--capath DIR]... 
            [--ciphers <cipherSuites>[:<cipherSuites>...]]... 
            [--tls-version <supportedTLSVersions>]... 
            [-Wd <willDelayInterval>] 
            [-We <willMessageExpiryInterval>] 
            [-Wm <willMessage>] 
            [-Wq <willQos>]   
            [-Wr] 
            [-Wt <willTopic>] 
            [-Wcd <willCorrelationData>]
            [-Wct <willContentType>] 
            [-Wpf <willPayloadFormatIndicator>]
            [-Wrt <willResponseTopic>] 
            [-Wup <willUserProperties>]...
            [--rcvMax <receiveMaximum>] 
            [--sendMax <sendMaximum>]
            [--maxPacketSize <maximumPacketSize>] 
            [--sendMaxPacketSize <sendMaximumPacketSize>] 
            [--topicAliasMax <topicAliasMaximum>] 
            [--sendTopicAliasMax <sendTopicAliasMaximum>]                                                                                  
            [--[no-]reqProblemInfo] 
            [--reqResponseInfo] 
            [--help] 
            [--version]

Option	Long Version	Explanation	Default
`-t`	`--topic`	The MQTT topic the client will subscribe to.
`-q`	`--qos`	Define the quality of service level. If only one QoS is specified it will be used for all topics. You can define a specific QoS level for every topic. The corresponding QoS levels will be matched in order to the given topics.	`0`
`-of`	`--outputToFile`	If a file is given print the received publishes to the specified output file. If the file is not present it will be created.
`-b64`	`--base64`	Whether the received publish messages will be base64 encoded.	`false`
`-J`	`--jsonOutput`	Print the received publishes in pretty JSON format.	`false`
`-T`	`--showTopics`	Prepend the specific topic name to the received publish.	`false`
`-up`	`--userProperty`	A user property of the subscribe message.

Connect Options

Option	Long Version	Explanation	Default
`-h`	`--host`	The MQTT host.	`localhost`
`-p`	`--port`	The MQTT port.	`1883`
`-V`	`--mqttVersion`	The MQTT version can be set to 3 or 5.	`MQTT v.5.0`
`-i`	`--identifier`	A unique client identifier can be defined.	A randomly generated UTF-8 String.
`-ip`	`--identifierPrefix`	The prefix for randomly generated client identifiers, if no identifier given.	`mqttClient`
	`--[no-]cleanStart`	Whether the client should start a clean session.	`true`
`k`	`--keepAlive`	The keep alive of the client (in seconds)	`60`
`-se`	`--sessionExpiryInterval`	Session expiry value in seconds.	`0` (Instant Expiry)
`-Cup`	`--connectUserProperty`	A user property of the subscribe message.
`--ws`		Use WebSocket transport protocol.	`false`
`--ws:path`		The path to the WebSocket located at given broker host.
`-l`		Log to ~./mqtt.cli/logs (Configurable through ~/.mqtt-cli/config.properties)	`false`

Security Options

Option	Long Version	Explanation	Default
`-s`	`--secure`	Whether a default SSL configuration is used.	`false`
`-u`	`--user`	Define the username for authentication.
`-pw`	`--password`	Define the password for authentication directly. If left blank the user will be prompted for the password in console.
`-pw:env`		Define that the password for authentication is read in from an environment variable.	`MQTT_CLI_PW` if option is specified without value
`-pw:file`		Define the path to a file from which the password is read in.
	`--cert`	The path to the client certificate to use for client-side authentication.
	`--key`	The path to the corresponding private key for the given client certificate.
	`--cafile`	The path to the file containing a trusted CA certificate to enable encrypted certificate based communication.
	`--capath`	The path to the directory containing trusted CA certificates to enable encrypted certificate based communication.
	`--ciphers`	The supported cipher suites in IANA string format concatenated by the ‘:’ character if more than one cipher should be supported. e.g `TLS_CIPHER_1:TLS_CIPHER_2` See IANA Format for supported cipher suite strings.
	`--tls-version`	The TLS version to use - `TLSv1.1` `TLSv1.2` `TLSv1.3`	`TLSv1.2`

Will Options

Option	Long Version	Explanation	Default
`-Wd`	`--willDelayInterval`	Will delay interval in seconds.	`0`
`-We`	`--willMessageExpiryInterval`	Lifetime of the will message in seconds. Can be disabled by setting it to `4_294_967_295`	`4_294_967_295` (Disabled)
`-Wm`	`--willPayload`	Payload of the will message.
`-Wq`	`--willQualityOfService`	QoS level of the will message.	`0`
`-Wr`	`--willRetain`	Retain the will message.	`false`
`-Wt`	`--willTopic`	Topic of the will message.
`-Wcd`	`--willCorrelationData`	Correlation data of the will message
`-Wct`	`--willContentType`	Description of the will message’s content.
`-Wpf`	`--willPayloadFormatIndicator`	Payload format can be explicitly specified as `UTF8` else it may be `UNSPECIFIED`.
`-Wrt`	`--willResponseTopic`	Topic Name for a response message.
`-Wup`	`--willUserProperty`	A user property of the will message.

Connect Restrictions

Long Version	Explanation	Default
`--rcvMax`	The maximum amount of not acknowledged publishes with QoS 1 or 2 the client accepts from the server concurrently.	`65535`
`--sendMax`	The maximum amount of not acknowledged publishes with QoS 1 or 2 the client send to the server concurrently.	`65535`
`--maxPacketSize`	The maximum packet size the client accepts from the server.	`268435460`
`--sendMaxPacketSize`	The maximum packet size the client sends to the server.	`268435460`
`--topicAliasMax`	The maximum amount of topic aliases the client accepts from the server.	`0`
`--sendTopicAliasMax`	The maximum amount of topic aliases the client sends to the server.	`16`
`--[no-]reqProblemInfo`	The client requests problem information from the server.	`true`
`--reqResponseInfo`	The client requests response information from the server.	`false`

Further Examples

Subscribe to one topic with default QoS Exactly Once

NOTE: If you specify one QoS and multiple topics, the QoS will be used for all topics.

$ mqtt sub -t topic1 -t topic2 -q 2

Subscribe to the given topics with a specific QoS for each topic. ('topic1' will have QoS 0, 'topic2' QoS 1 and 'topic3' QoS 2)

$ mqtt sub -t topic1 -q 0 -t topic2 -q 1 -t topic3 -q 2

Subscribe to a topic and output the received publish messages to the file publishes.log in the current directory

NOTE: If the file is not created yet it will be created by the CLI. If it is present the received publish messages will be appended to the file.

$ mqtt sub -t topic -of publishes.log

Subscribe to a topic and output the received publish messages to the file publishes.log in a specified /usr/local/var directory

NOTE: If the file is not created yet it will be created by the CLI. If it is present the received publish messages will be appended to the file.
$ mqtt sub -t topic -of /usr/local/var/publishes.log

Subscribe to a topic and output all the received messages in base64 encoding

$ mqtt sub -t topic -b64

Subscribe

Simple Examples

Synopsis

Subscribe Options

Connect Options

Security Options

Will Options

Connect Restrictions

Further Examples

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