# MATLAB: How to change line specifications for frequency response

line

Hi everybody,
I would like to plot a response to an initial condition in the frequency domain such as:
initial(G1,initial_state,'k','--')
However, even though I can change the graph color, I can not change the line type or line width and get the following error: "Invalid syntax for time or frequency response command."
Does anybody know how to adapt plot specifications?
[y,t,x] = initial(G1, initial_state);figure(1)plot(t, y,    t, zeros(numel(t),1),':')