xdotool search --onlyvisible --name firefoxxdotool windowsize $WINDOW_ID_GOES_HERE $WIDTH $HEIGHTxdotool windowmove $WINDOW_ID_GOES_HERE $X $YFor example, if the window id for firefox is 123 you would do this:
xdotool windowsize 123 800 600xdotool search --onlyvisible --name firefoxxdotool windowsize $WINDOW_ID_GOES_HERE $WIDTH $HEIGHTxdotool windowmove $WINDOW_ID_GOES_HERE $X $YFor example, if the window id for firefox is 123 you would do this:
xdotool windowsize 123 800 600