def parse_variable_usage(file)
      grep_output = `grep -iG "\\$" #{file}`
      grep_output.each_line do |line|
        matches = line.scan(/\$[\w-]*/)
        matches.each do |match|
          match.gsub!('$', '')
          self.variable_usage[match] ||= 0
          self.variable_usage[match] += 1
        end
      end
    end
def parse_variable_usage(file)
      grep_output = `grep -iG "\\$" #{file}`
      grep_output.each_line do |line|
        matches = line.scan(/\$[\w-]*/)
        matches.each do |match|
          match.gsub!('$', '')
          self.variable_usage[match] ||= 0
          self.variable_usage[match] += 1
        end
      end
    end
count the usages of all the Sass variables