How to get email text via Curl (IMAP/POP)?

Question

IMAP

Good afternoon. The problem is that I can not figure out how to get the text of the letter. Navigating through folders and getting titles I do without problems. I read from the documentation and examples that you need to pass the following parameters:
curl -X "FETCH letter_number BODY" link . in response I get "FETCH BODY number {number}". I assume that this is the size of the message body, but I don’t understand what to do next. BODY[TEXT] etc didn't solve the problem. Server - gmail.
What should be the parameters for receiving the text of the letter?