Command_line command not working

Dear All,
I am trying to use the following sensor:

- platform: command_line
  command: "ha supervisor info | awk '/version:/{print $2}' | awk 'FNR==3'"
  name: Current Supervisor
  scan_interval: 86400

It doesn’t seem to do much. I presume it is because HA is running in a Docker container, and when I open an Exec console in Portainer, it doesn’t even find the command ha.

What is the recommended way of dealing with this issue?
The documentation clearly suggests the using of the ha command.

Why is it not working for me? Other, more basic, commands work just fine, i.e. this:

- platform: command_line
  name: Python Version
  command: python3 --version
  scan_interval: 86400

Thanks in advance for any pointers!

Edit:
It works from the hassio_cli container’s Exec console…