hi all
I am fresh with ros2
i am getting this error, anyone can help
…6HB:~$ ros2 run demo_nodes_
usage: ros2 run [-h] [–prefix PREFIX] package_name executable_name …
ros2 run: error: the following arguments are required: executable_name, argv
Seems like you didnt enter the full ROS 2 command. Its needs package name and node name so that is why its complaining as the error message says. Try entering the full cmd
ros2 run demo_nodes_cpp talker
Mind that this ROS discourse is not really for support but https://robotics.stackexchange.com/ is. But in this case, just a google and another run of the tutorial would have helped already. There is more information in the error message than you think 
thanks for your reply
i will run again the tutorial
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