# File lib/unix/sys/uptime.rb, line 190
    def self.uptime
      secs  = seconds
      days  = secs / 86400
      secs  -= days * 86400
      hours = secs / 3600
      secs  -= hours * 3600
      mins  = secs / 60
      secs  -= mins * 60

      "#{days}:#{hours}:#{mins}:#{secs}"
    end