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mosquitto_pub — A simple MQTT version 3.1.1 client that will publish a single message on a topic and exit. More info

Submitted by: @import:tldr-pages·Mar 2, 2026·

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Problem

How to use the mosquitto_pub command: A simple MQTT version 3.1.1 client that will publish a single message on a topic and exit. More information: <https://mosquitto.org/man/mosquitto_pub-1.html>.

Solution

mosquitto_pub — A simple MQTT version 3.1.1 client that will publish a single message on a topic and exit. More information: <https://mosquitto.org/man/mosquitto_pub-1.html>.

Publish a temperature value of 32 on the topic sensors/temperature to 192.168.1.1 (defaults to localhost) with Quality of Service (QoS) set to 1:

mosquitto_pub {{[-h|--host]}} {{192.168.1.1}} {{[-t|--topic]}} {{sensors/temperature}} {{[-m|--message]}} {{32}} {{[-q|--qos]}} {{1}}

Publish timestamp and temperature data on the topic sensors/temperature to a remote host on a non-standard port:

mosquitto_pub {{[-h|--host]}} {{192.168.1.1}} {{[-p|--port]}} {{1885}} {{[-t|--topic]}} {{sensors/temperature}} {{[-m|--message]}} "{{1266193804 32}}"

Publish light switch status and retain the message on the topic switches/kitchen_lights/status to a remote host because there may be a long period of time between light switch events:

mosquitto_pub {{[-r|--retain]}} {{[-h|--host]}} "{{iot.eclipse.org}}" {{[-t|--topic]}} {{switches/kitchen_lights/status}} {{[-m|--message]}} "{{on}}"

Send the contents of a file (data.txt) as a message and publish it to sensors/temperature topic:

mosquitto_pub {{[-t|--topic]}} {{sensors/temperature}} {{[-f|--file]}} {{data.txt}}

Send the contents of a file (data.txt), by reading from stdin and send the entire input as a message and publish it to sensors/temperature topic:

mosquitto_pub < {{data.txt}} {{[-t|--topic]}} {{sensors/temperature}} {{[-s|--stdin-file]}}

Read newline delimited data from stdin as a message and publish it to sensors/temperature topic:

{{echo data.txt}} | mosquitto_pub {{[-t|--topic]}} {{sensors/temperature}} {{[-l|--stdin-line]}}

Code Snippets

Publish a temperature value of 32 on the topic `sensors/temperature` to 192.168.1.1 (defaults to `localhost`) with Quality of Service (`QoS`) set to 1

mosquitto_pub {{[-h|--host]}} {{192.168.1.1}} {{[-t|--topic]}} {{sensors/temperature}} {{[-m|--message]}} {{32}} {{[-q|--qos]}} {{1}}

Publish timestamp and temperature data on the topic `sensors/temperature` to a remote host on a non-standard port

mosquitto_pub {{[-h|--host]}} {{192.168.1.1}} {{[-p|--port]}} {{1885}} {{[-t|--topic]}} {{sensors/temperature}} {{[-m|--message]}} "{{1266193804 32}}"

Publish light switch status and retain the message on the topic `switches/kitchen_lights/status` to a remote host because there may be a long period of time between light switch events

mosquitto_pub {{[-r|--retain]}} {{[-h|--host]}} "{{iot.eclipse.org}}" {{[-t|--topic]}} {{switches/kitchen_lights/status}} {{[-m|--message]}} "{{on}}"

Send the contents of a file (`data.txt`) as a message and publish it to `sensors/temperature` topic

mosquitto_pub {{[-t|--topic]}} {{sensors/temperature}} {{[-f|--file]}} {{data.txt}}

Send the contents of a file (`data.txt`), by reading from `stdin` and send the entire input as a message and publish it to `sensors/temperature` topic

mosquitto_pub < {{data.txt}} {{[-t|--topic]}} {{sensors/temperature}} {{[-s|--stdin-file]}}

Context

tldr-pages: common/mosquitto_pub

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