# File lib/childprocess.rb, line 64
    def os
      @os ||= (
        require "rbconfig"
        host_os = RbConfig::CONFIG['host_os']

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