how to find steady state error in matlab code example

Example: matlab online for steady state error

s = tf('s');
G = (4/(s+2));
T = feedback(G,(2/s+4));
t = 0:0.1:25;
u = t;
[y,t,x] = lsim(T,u,t);
plot(t,y,'y',t,u,'m')
xlabel('Time (sec)')
ylabel('Amplitude')
title('Input-purple, Output-yellow')