Library /sys$common/syshlp/mailhelp.hlb MAIL, Qualifiers, /SUBJECT  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /SUBJECT="subject-text"

    Prompts for the subject of the mail message to be sent. Use
    quotation marks (" ") around the subject heading to include more
    than one word, to print in lowercase letters, or to include any
    spaces or nonalphanumeric characters.