Moves the current message to the specified folder. You can use
    the FILE command and the MOVE command interchangeably because
    they work the same way. Note, however, that the FILE command
    deletes the message from the original folder, unlike the COPY
    command, which leaves a copy.

    If (after entering the FILE command, pressing Return, and
    supplying a folder name at the prompt, but before pressing Return
    again), you decide that you do not want to file the message,
    press Ctrl/C. Ctrl/C terminates the operation and keeps you
    within Mail.

    If you omit the folder and file name parameters, Mail prompts
    you for both. If you supply only the foldername, Mail uses the
    current mail file and does not prompt you for the file name.

    Format

      FILE  foldername [file-spec]