PostScript :: SETDASH - Drawing Dotted Line / Broken Line
Operator: [a b c d ...] w setdash
sets the dash pattern parameter
Example:
%! newpath 100 700 translate 0 0 moveto [8 8] 0 setdash 400 0 rlineto stroke 0 -100 moveto [] 0 setdash 400 0 rlineto stroke showpage