Okay, will try that.
HOWEVER, in the docs, it says:
To load the secret from a file:
data_bag_item('bag', 'item', IO.read('secret_file'))
There's nothing about IO.read(…).strip…
And, well, why do I need to use strip in the first place? I mean, when I called knife …, I gave it the full file, not just some parts of it.