grep.rb

#!/usr/bin/env ruby

fail "Please specify a string first and then the directory second" if ARGV.size != 2

query, location = *ARGV
puts "you're looking for #{query} in #{location}"

def grep(query, file)
  File.open file do |fd|
    fd.each_line do |line|
      puts line.chomp if line.include? query
    end
  end
end

puts "Results:"

if File.directory?(location)
  require 'find'
  Find.find(location) do |path|
    grep(query, path) if File.file?(path)
  end
else
  grep(query, location)
end