CHANGE SEGMENT_NAMES

        The 'SegName' used in all the CHANGE commands is formed by  a  name,
    given  by  the  calling  high-level  program  (usually a reminder of the
    command used), followed by an unique, incremental, number.  To  refer  a
    particular    segment,    one    uses    the    full    name    (as   in
    CHANGE VISIBILITY CONTOUR:46 OFF). To refer to ALL the segments with the
    same  name,  omit  the  number (as in CHANGE VISIBILITY CONTOUR OFF). To
    refer to a range of segments, use a 'minus' sign in  the  range  (as  in
    CHANGE VISIBILITY CONTOUR:32-46 OFF). Segments names can be 'wildcarded'
    (an '*' can replace part of the beginning or  the  end  of  the  segment
    name, as in CHANGE VISIBILITY *TOUR OFF).

    Trick: A reverse range of segments (as in CLEAR SEGMENT 32-12) is valid.
    In  the  particular  case  of the above example, it is equivalent to the
    command CHANGE VISIBILITY 32-12 CLEAR wich in turns tries to delete  (as
    opposed  to  change  the  visibility) the segments (which is possible if
    segment 32 is the last segment plotted).