Add functions similar to .b click,but instread of mouse,you can use let's say #pos1 and it will select first position at your feet [or you could #pos1 100 10 100 to select coordonates] then #pos2 with the same effect,then allow stuff like #fill [block] or #cleanarea

#goal -> pos1
#cleararea at pos 2

@stijnsimons and to fill an area with blocks you use which command, hmm?