# File lib/childprocess.rb, line 90
    def os
      @os ||= (
        require "rbconfig"
        host_os = RbConfig::CONFIG['host_os'].downcase

        case host_os
        when /linux/
          :linux
        when /darwin|mac os/
          :macosx
        when /mswin|msys|mingw32/
          :windows
        when /cygwin/
          :cygwin
        when /solaris|sunos/
          :solaris
        when /bsd/
          :bsd
        else
          raise Error, "unknown os: #{host_os.inspect}"
        end
      )
    end