Brute Force String Pattern matching in Ruby

brute_search.rb

sentence = "soijasdoijasdiojfuhfuhsdfhoscaroijasdoijasdijd"
n = sentence.length

key = "oscar"
l = key.length

i = 0
while i < n do
	j = 0 
	puts sentence[i]
	while j < l && sentence[i] == key[j] do
		puts "#{sentence[i]} - #{key[j]}"
		if sentence[i]==key[l-1]
			puts "Yes"
		end
		i += 1
		j += 1
	end
	i += 1
end