Hot to get the data of the STEP input (u) instead of the output respond ([y,t]= step(sys)?

I want to plot the step input curve of my process below my output response.

Answer 1

[Azzi Abdelmalek]

%for continuous system 
%e.g   H(p) =1/(p+2)
N=1
D=[1 2]
model=tf(N,D)
[y,t]=step(model,[0:0.1:10])
plot(t,y)