Ruby equivalent to Python __main__ [duplicate]

Question

If in a ruby file I define a function like so:

def tell_the_truth()
    puts "truth"
end

is there an equivalent to python's main?

if __name__ == "__main__":
    tell_the_truth()

Is it to simply call the function inside the file?

tell_the_truth

Answer 1

I believe this will work:

if __FILE__ == $0
    tell_the_truth()
end

Answer 2

if __FILE__ == $PROGRAM_NAME
    tell_the_truth()
end