Essential ROS 2 Commands

The collection of the most essential ROS 2 commands for managing nodes, topics, services, and actions. A cheat sheet for ROS 2 commands that I hope you find useful.

General

Programs

Starting rqt command GUI

rqt

Starting graph visualization software (rqt_graph)

rqt_graph

Repeating Patterns

Many commands are shared across nodes, topics, services, and actions. For example ros2 node list and ros2 topic list. Here are some relevant repeating commands to remember:

• list
• info

Whenever you are unsure, use the --help option.

Packages

List available ROS 2 packages

ros2 pkg list

Displays all installed ROS 2 packages.

Show executables in a package

ros2 pkg executables <package_name>

Lists all executables provided by a specific package.

Show ROS 2 environment variables

printenv | grep ROS

Displays environment variables related to ROS 2.

Check the ROS 2 version

ros2 --version

Displays the installed ROS 2 version.

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Nodes

List active nodes

ros2 node list

Lists all active nodes currently running.

Get information about a node

ros2 node info <node_name>

Shows details about a specific node, such as subscribed topics, published topics, and services.

Run a node from a package

ros2 run <package_name> <executable_name>

Launches an executable (node) from a given package.

Launch multiple nodes with a launch file

ros2 launch <package_name> <launch_file>

Executes a launch file that can start multiple nodes and set parameters.

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Topics

List topics

ros2 topic list

Shows all active topics in the system.

Echo messages

ros2 topic echo <topic_name>

Prints messages published on a topic to the console. This creates a debug node in the graph. You can check this with rqt_graph.

Publish messages

ros2 topic pub <topic_name> <message_type> "<message_data>"

Publishes a message (use quotes for JSON/YAML-like data).

Example:

ros2 topic pub /chatter std_msgs/msg/String "data: 'Hello, ROS 2!'"

A more complicated example: In the turtlesim package, one can publish vectors to cmd_vel topic of type Twist:

ros2 topic pub /turtle1/cmd_vel geometry_msgs/msg/Twist "{linear: {x: 2.0, y: 0.0, z: 0.0}, angular: {x: 0.0, y: 0.0, z: 1.8}}"

For the format of such messages, please refer to "Show interface definition" section.

Show topic type

ros2 topic type <topic_name>

Displays the message type used by the specified topic.

Check message rate

ros2 topic hz <topic_name>

Measures and displays the rate at which messages arrive on a topic.

Check bandwidth usage

ros2 topic bw <topic_name>

Monitors bandwidth usage on a topic.

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Services

List available services

ros2 service list

Displays all active services. For a list of all services with their types:

ros2 service list -t

Show service type

ros2 service type <service_name>

Displays the service type used by a specific service.

Call a service

ros2 service call <service_name> <service_type> "<request_data>"

Sends a request to a service.

Example:

ros2 service call /add_two_ints example_interfaces/srv/AddTwoInts "{a: 5, b: 10}"

For the format of such request data please refer to "Show interface definition" section.

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Actions

List actions

ros2 action list

Lists all active action servers.

Displays all active actions. For a list of all actions with their types:

ros2 action list -t

Show action type/interface

ros2 action show <action_type>

Displays the structure of an action type (goal, feedback, and result).

Send a goal

ros2 action send_goal <action_name> <action_type> "<goal_data>"

Sends a goal to an action server. Once can place the option --feedback at the end to get data back while the action is underway.

For the format of such goal data, please refer to "Show interface definition" section.

Example:

ros2 action send_goal /fibonacci action_tutorials_interfaces/action/Fibonacci "{order: 5}"

Echo feedback

ros2 action echo <action_name>

Prints live feedback from an action server on a given action.

Cancel a goal

ros2 action cancel <action_name> <goal_id>

Cancels a specific goal in progress (goal ID is optional; if omitted, all goals may be canceled).

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Interfaces

Want to know the format of the input message, response message, or feedback message? Use the interface commands.

Show interface definition

ros2 interface show <type_name>

Displays the fields of a message, service, or action type.

List all interfaces

ros2 interface list

Lists all available interfaces. Narrow the list to messages (-m), services (-s), or actions (-a):

ros2 interface list -m
ros2 interface list -s
ros2 interface list -a

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Parameters

List parameters for a node

ros2 param list <node_name>

Lists all declared parameters and their values for a specific node.

Get parameter value

ros2 param get <node_name> <param_name>

Retrieves the current value of a parameter from a node.

Set parameter value

ros2 param set <node_name> <param_name> <value>

Sets a parameter on a running node.

Describe a parameter

ros2 param describe <node_name> <param_name>

Displays detailed information (type, description, constraints) about a parameter.

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This document provides a quick reference for useful ROS 2 commands. It may be updated from feedback or my own experiences.