The correct answer is: rostopic echo.
- rostopic bw displays the bandwidth of a topic.
- rostopic delay displays the average delay of messages published to a topic.
- rostopic echo displays messages published to a topic.
- rostopic hz displays the frequency of messages published to a topic.
rostopic echo is a command-line tool that can be used to display messages published to a topic. It takes the name of the topic as an argument and prints out all of the messages that have been published to that topic since the last time the tool was run.
For example, to display all of the messages that have been published to the topic /chatter, you would run the following command:
rostopic echo /chatter
This would print out all of the messages that have been published to the topic, one per line.
The output of rostopic echo can be useful for debugging applications that are publishing messages to topics. It can also be used to monitor the activity of a topic, such as the number of messages that are being published per second.