mosquitto_pub and mosquitto_sub commands in IOT Protocols - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the command to publish a message 'Hello' to topic 'test/topic' using mosquitto_pub.

IOT Protocols

mosquitto_pub -t [1] -m "Hello"

Drag options to blanks, or click blank then click option'

Amqtt/topic

Bhello/world

Ctest/topic

Dtopic/test

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong topic name.

Confusing the topic with the message.

The -t option specifies the topic to publish to. Here, 'test/topic' is the correct topic.

2fill in blank

medium

Complete the command to subscribe to the topic 'sensor/data' using mosquitto_sub.

IOT Protocols

mosquitto_sub -t [1]

Drag options to blanks, or click blank then click option'

Adata/sensor

Bsensor/data

Csensor/info

Ddata/sensors

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping words in the topic name.

Using a similar but incorrect topic.

The -t option specifies the topic to subscribe to. 'sensor/data' is the correct topic here.

3fill in blank

hard

Fix the error in the command to publish message 'Data' to topic 'home/room' with QoS level 1.

IOT Protocols

mosquitto_pub -t home/room -m Data -q [1]

Drag options to blanks, or click blank then click option'

A1

B2

C0

D3

Attempts:

3 left

💡 Hint

Common Mistakes

Using invalid QoS levels like 3.

Confusing QoS with other options.

The -q option sets the QoS level. Valid values are 0, 1, or 2. Here, QoS 1 is required.

4fill in blank

hard

Fill both blanks to subscribe to topic 'alerts' with verbose output and clean session disabled.

IOT Protocols

mosquitto_sub -t [1] [2]

Drag options to blanks, or click blank then click option'

Aalerts

B-v

C-c

D--clean-session

Attempts:

3 left

💡 Hint

Common Mistakes

Using --clean-session which enables clean session.

Not using verbose mode when needed.

The topic is 'alerts'. The -v option enables verbose output. Clean session is disabled by default, so no extra option is needed here.

5fill in blank

hard

Fill all three blanks to publish message 'Update' to topic 'device/status' with retain flag and QoS 2.

IOT Protocols

mosquitto_pub -t [1] -m [2] [3] -q 2

Drag options to blanks, or click blank then click option'

Adevice/status

B"Update"

C-r

D-d

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting quotes around the message.

Using -d which enables debug mode instead of retain.

The topic is 'device/status'. The message must be quoted as "Update". The -r option sets the retain flag.