Replace a symbolic variable with a symbolic expression

Hi eveyone. I've the following code:

close all
clear all
syms t
Y=fourier(heaviside(t));

The result is Y = pi*dirac(w) - 1i/w. My goal is to replace w with 2*pi*f. How can I do that?

Thank you for your help.

Answer 1

[John D'Errico]

Subs does this directly.

help subs

[Gennaro Arguzzi]

Hi John D'Errico, I just tried with subs, but it works only if the first input is pi*dirac(w) - 1i/w. Instead in my code I have Y.