16. ROS2 Common Command Tools

1. Package Management Tool ros2 pkg

1.1. ros2 pkg create

Function: Creates a package. When creating a package, you must specify the package name, compilation method, dependencies, etc.

Format:

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ros2 pkg create <package_name> --build-type <build-type> --dependencies <dependencies>

In the ros2 command:

• pkg: Indicates the functions associated with the package;
• create: Indicates the creation of a package;
• package_name: Required: The name of the new package;
• build-type: Required: Indicates whether the newly created package is C++ or Python. If using C++ or C, follow ament_cmake; if using Python, follow ament_python;
• dependencies: Optional: Indicates the package's dependencies. C++ packages must include rclcpp; Python packages must include rclpy, as well as other required dependencies.

1.2, ros2 pkg list

Function: View the list of packages in the system

Format:

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ros2 pkg list

1.3. ros2 pkg executables

Function: View all executable files in a package

Format:

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ros2 pkg executables pkg_name

2. Node Run ros2 run

Function: Run the node program in the package

Format:

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ros2 run pkg_name node_name

• pkg_name: Package name
• node_name: The name of the executable program

3. Node-Related Tools: ros2 node

3.1. ros2 node list

Function: Lists all node names in the current domain

Format:

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ros2 node list

3.2. ros2 node info

Function: View detailed node information, including subscriptions, published messages, enabled services, and actions.

Format:

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ros2 node info node_name

• node_name: The name of the node to be viewed.

4. Topic-Related Tools: ros2 topic

4.1. ros2 topic list

Function: List all topics in the current domain

Format:

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ros2 topic list

4.2. ros2 topic info

Function: Display topic message type and number of subscribers/publishers

Format:

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ros2 topic info topic_name

• topic_name: The name of the topic to be queried.

4.3, ros2 topic type

Function: View the message type of a topic

Format:

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ros2 topic type topic_name

• topic_name: The name of the topic type to be queried.

4.4, ros2 topic hz

Function: Display the average publishing frequency of a topic.

Format:

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ros2 topic hz topic_name

• topic_name: The name of the topic whose frequency you want to query.

4.5, ros2 topic echo

Function: Print topic messages on the terminal, similar to a subscriber.

Format: ros2 topic echo topic_name

• topic_name: The name of the topic whose messages you want to print.

4.5, ros2 topic pub

Function: Publish a message on a specified topic on the terminal.

Format:

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ros2 topic pub topic_name message_type message_content

• topic_name: The name of the topic whose messages you want to publish.
• message_type: The data type of the topic.
• message_content: Message content

The default is to publish at a 1Hz frequency. The following parameters can be set:

• Parameter -1 to publish only once, ros2 topic pub -1 topic_name message_type message_content
• Parameter -t count to publish count times, ros2 topic pub -t count topic_name message_type message_content
• Parameter -r count to publish at a count Hz frequency, ros2 topic pub -r count topic_name message_type message_content

Example:

• Publish velocity commands via the command line
• Note that there is a space after each colon; otherwise, a format error will be displayed.

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ros2 topic pub turtle1/cmd_vel geometry_msgs/msg/Twist "{linear: {x: 0.5, y: 0.0, z: 0.0}, angular: {x: 0.0, y: 0.0, z: 0.2}}"

5. Interface-Related Tools: ros2 interface

5.1. ros2 interface list

Function: Lists all interfaces in the current system, including topics, services, and actions.

Format:

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ros2 interface list

5.2. ros2 interface show

Function: Displays the detailed information of a specified interface

Format:

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ros2 interface show interface_name

• interface_name: The name of the interface to be displayed

6. Service-Related Tools ros2 service

6.1. ros2 service list

Function: Lists all services in the current domain

Format:

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ros2 interface show interface_name

6.2, ros2 service call

Function: Call a specified service

Format:

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ros2 interface call service_name service_Type arguments

• service_name: The service to be called
• service_type: The service data type
• arguments: The parameters required to provide the service

For example, to call the turtle spawn service

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ros2 service call /spawn turtlesim/srv/Spawn "{x: 2, y: 2, theta: 0.2, name: 'turtle10'}"