ROS Pub / Sub demo

pub.py

"""
Publisher demo
"""
import rospy
from std_msgs.msg import String


rospy.init_node('my_second_node_description')

topic_name = "/test"

pub = rospy.Publisher(topic_name, String)

pub.publish(String("Hello world!"))

pubsub.bash

# in bash
rostopic pub /test std_msgs/String "Hello world!"
rostopic echo /test

sub.py

"""
Subscriber demo
"""
import rospy
from std_msgs.msg import String


rospy.init_node('my_first_node_description')

def callback(message):
    # see: ros.org/doc/api/std_msgs/html/msg/String.html
    print(message.data)

topic_name = "/test"

sub = rospy.Subscriber(topic_name, String, callback)