Like to sent a http command using System Command Editor

I like to send the following command to an other Raspberry to switch ob the power outlet for my printer:

It dosen't work if I just use the command. Is there any other possibility?

It works with
curl -m 2 http://:@

I also want to send a shutdown command to OptoPi. But shutdown -h now needs root privileges. Which command does OctoPrint use?