Repetitive copy-pasting of IDs

[pranasziaukas]

Everyone reproducing the masterclass diligently has to edit commands a bunch of times and insert their otherwise static device and application IDs a bunch of times.
Some of the entries are more cryptic than others. For example, at the start of section 5.3 after copy-pasting

curl -X GET 'https://api.balena-cloud.com/v5/device?$filter=belongs_to__application%20eq%20%271550049%27%20and%20is_online%20eq%20true' -H "Authorization: Bearer $API_TOKEN" -H 'Content-Type: application/json'

one has to delete 1550049 and replace it with their own ID obtained from the result of balena apps | grep FleetMasterclass.

I am wondering whether it adds any value to the masterclass.

Maybe we could store static IDs in environment variables just like it's done with the token API_TOKEN=<YOUR_API_TOKEN>.