What output do you expect when running mosquitto_pub -h localhost -t sensors/temperature -m "22.5" and simultaneously running mosquitto_sub -h localhost -t sensors/temperature in another terminal?

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Raspberry Pi - MQTT for IoT

What output do you expect when running mosquitto_pub -h localhost -t sensors/temperature -m "22.5" and simultaneously running mosquitto_sub -h localhost -t sensors/temperature in another terminal?

AAn error message appears indicating connection failure

BThe publisher terminal displays the message: 22.5

CBoth terminals remain silent with no output

DThe subscriber terminal displays the message: 22.5

Step-by-Step Solution

Solution:

Step 1: Understand the commands
mosquitto_pub publishes a message to a topic, and mosquitto_sub subscribes to that topic to receive messages.
Step 2: Analyze the topic and message
The publisher sends "22.5" to the topic sensors/temperature, which the subscriber listens to.
Final Answer:
The subscriber terminal will display the message: 22.5 -> Option D
Quick Check:
Subscriber receives published message [OK]

Quick Trick: Subscriber shows messages published to its topic [OK]

Common Mistakes:

MISTAKES

Expecting publisher to display the message
Thinking no output appears without explicit print
Assuming error without broker running

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What output do you expect when running mosquitto_pub -h localhost -t sensors/temperature -m "22.5" and simultaneously running mosquitto_sub -h localhost -t sensors/temperature in another terminal?

Step 1: Understand the commands

Step 2: Analyze the topic and message

Final Answer:

Quick Check:

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