File.readable? How To Make It Work?

=begin
The following block of code belongs to a program that is under construction currently
=end

print "File name: "
filename = gets.chomp

if File.readable?("#{filename}")

File.open("#{filename}", "r") do |f|
  f.each_line do |line|
    puts line
  end
end

else puts "The given file '#{filename}' is not readable."
end