Send an email from the command line with Mutt
$ mutt -s subject -b address_to_bcc -c address_to_cc -a file_to_attach -- recipient_address < message.txt
where message.txt is a file with a message written in plain text.
The shell might print this message: “Fcc to an IMAP mailbox is not supported in batch mode” after you’ve run the command, note however that the message will have been sent successfully.
I looked through Mutt’s manual and suppose that “bach mode” means “sent from the command line” and that
fcc has to do with saving outgoing message to specific folders. I noticed that when the shell outputs this message, emails are not saved to
$ man mutt