/sys$common/syshlp/helplib.hlb SEARCH, Qualifiers, /HIGHLIGHT  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /HIGHLIGHT[=keyword]
       /NOHIGHLIGHT (default)

    You can use one of the following keywords: BOLD, BLINK,
    REVERSE, and UNDERLINE. BOLD is the default highlighting on
    ANSI video terminals with advanced video; REVERSE is the default
    highlighting on ANSI video terminals without advanced video.

    For hardcopy printing, you can use the HARDCOPY=OVERSTRIKE and
    HARDCOPY=UNDERLINE keywords. This specifies that the strings
    should be highlighted in a manner suitable for most hardcopy
    printers. With overstrike highlighting, matched strings are
    double-printed, so that they appear darker. The matched strings
    are underlined with the underscore character.

    Hardcopy printing is accomplished by adding a carriage return and
    spacing back over the line to overprint the string or underlines.
    Note that this can as much as double the length of the line,
    and perhaps lead to truncation if the device buffer size is too
    small.

    Compaq recommends that you use the /HIGHLIGHT=UNDERLINE
    qualifier with the LN01 printer rather than using the
    /HIGHLIGHT=HARDCOPY=UNDERLINE qualifier. The LN01 printer ignores
    OVERSTRIKE highlighting.

    Compaq recommends that you use either the /HIGHLIGHT=BOLD or
    the /HIGHLIGHT=UNDERLINE qualifier with the LN03 printer rather
    than using the /HIGHLIGHT=HARDCOPY=UNDERLINE qualifier. The LN03
    printer ignores OVERSTRIKE highlighting.