As with the root locus plots, it will be tempting to rely exclusively on MATLAB to obtain Bode, Nyquist, and other frequency-response plots. We strongly recommend that MATLAB should be treated as one tool in the tool kit that can be used to design and analyze control systems. There is no substitute for a clear understanding of the underlying theory.
MATLAB font does not permit the frequency symbol 
, which will appear as w in our MATLAB codes. Also note that the default unit for frequency is rad/sec. This can be altered, if required, to hertz by editing the plot axes; but we will continue to use rad/sec