Change rebar marking type
 
  File name : CB.LSP

  This program change the rebar mark type. It adds under line to circle type mark.
     Example 
  Command: cb
  Select objects: {p1} {p2}   [Select mark circle and diameter text]
  Select objects:      [Type enter to finish selecting]
  Pick basepoint: end of {p3} [Pick start point of underline]
  Pick sidepoint: {P4}         [Pick side position of underline]