If , for some reason , you don t want to shut the system down but you want to send a warning to users anyway that the system is shutting down , use the " - k " argument with the shutdown command 如果出于某些原因，您不想关闭系统，但却要向用户发送“系统即将关闭”的警告，那么应在shutdown中使用" - k "自变量。
Existing approaches in defending ddos intrusions is just close service even close the system . but it is improbable for some crucial service . even the application could accept , obviously , it is n ' t a kind of superior strategy 在受到分布式攻击时，当前的做法是关闭服务甚至关闭系统，这对于一些提供关键数据服务的系统是不能接受的，即使应用可以接受，这显然也不是一种最优策略。
On the other hand , a properly configured ups can alert the system of the power outage and send telinit init the sigpwr signal , which will cause init to bring the system into single - user mode or shut the system down altogether , depending on how it s configured 另一方面，正确配置的ups可以提醒系统断电情况，并向telinit / init发送sigpwr信号，这会使init根据其配置情况将系统切换到单用户方式或者完全关闭系统。
To be high available , a . core router should allow the insertion and extraction of boards without adversely affecting system operation . also it should allow its system reconfiguration and its fault recovery to take place with no system down time and minimum operator interaction 为了满足高可用性的要求，核心路由器应该支持系统运行时的设备板的插入和拔出，支持在不关闭系统和操作员干预尽可能少的情况下的系统重组和恢复，支持对故障的隔离。
