char_combination.rb

def input_str
	ret = []
	ret.concat(("a".."z").to_a)
	ret.concat(("A".."Z").to_a)
	ret.concat(("0".."9").to_a)
	return ret
end
INPUT = input_str()
def write_pass(input)
	
end
def pass_str(count)
	ret = [""]
	for i in 0...count
		pass_clone = ret.clone
		ret = []
		pass_clone.each do |pass|
			INPUT.each do |input|
				ret.push(pass + input)
				puts pass + input
			end
		end
	end
	return ret
end
for i in 1..4
	pass_str(i)
end
=begin
pass_str(4).each do |pass|
	INPUT.each do |input|
		puts pass + input
	end
end
=end

how to use: ruby char_combination.rb > result.txt