16. ROS2 Common Command Tools

Note: The accompanying reference video uses the ROS Humble version, for reference only

1. Package Management Tool - ros2 pkg

1.1. ros2 pkg create

Function: Create a package. When creating, you need to specify package name, build type, dependencies, etc.

Format:

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

In ros2 command:

• pkg: Package-related functionality;

• create: Create a package;

• package_name: Required: Name of the new package;

• build-type: Required: Indicates whether the new package is C++ or Python. Use ament_cmake for C/C++, or ament_python for Python;

• dependencies: Optional: Package dependencies. C++ packages need rclcpp, Python packages need rclpy, plus other needed dependencies;

1.2. ros2 pkg list

Function: List all 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 Execution - ros2 run

Function: Run a package node program

Format:

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ros2 run pkg_name node_name

• pkg_name: Package name

• node_name: Executable program name

3. Node-related Tools - ros2 node

3.1. ros2 node list

Function: List 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, services, and actions

Format:

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ros2 node info node_name

• node_name: Name of the node to query

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, number of subscribers/publishers

Format:

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ros2 topic info topic_name

• topic_name: Name of the topic to query

4.3. ros2 topic type

Function: Check the message type of a topic

Format:

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ros2 topic type topic_name

• topic_name: Name of the topic to query type for

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: Name of the topic to query frequency for

4.5. ros2 topic echo

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

Format: ros2 topic echo topic_name

• topic_name: Name of the topic to print messages from

4.5. ros2 topic pub

Function: Publish a specified topic message in the terminal

Format:

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ros2 topic pub topic_name message_type message_content

• topic_name: Name of the topic to publish to

• message_type: Data type of the topic

• message_content: Message content

By default, it publishes at 1Hz continuously. You can set the following parameters:

• Parameter -1: Publish only once. ros2 topic pub -1 topic_name message_type message_content

• Parameter -t count: Publish count times then end. ros2 topic pub -t count topic_name message_type message_content

• Parameter -r count: Publish continuously at count Hz. ros2 topic pub -r count topic_name message_type message_content

Example:

• Publish velocity command via command line

• Note: There is a space after each colon, otherwise a format error will be reported

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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: List 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: Display detailed content of a specified interface

Format:

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ros2 interface show interface_name

• interface_name: Name of the interface to display

6. Service-related Tools - ros2 service

6.1. ros2 service list

Function: List 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: Service to call

• service_Type: Service data type

• arguments: Parameters needed to provide the service

For example, call the spawn turtle service:

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