# File lib/guard/notifiers/notifysend.rb, line 28
      def available?(silent = false)
        if (RbConfig::CONFIG['host_os'] =~ /linux|freebsd|openbsd|sunos|solaris/) and (not `which notify-send`.empty?)
          true
        else
          ::Guard::UI.error 'The :notifysend notifier runs only on Linux, FreeBSD, OpenBSD and Solaris with the libnotify-bin package installed.' unless silent
          false
        end
      end