Linux命令学习总结：shutdown
命令简介：
该命令可以安全关闭或者重新启动系统。你没有看错，shutdown命令不仅可以关闭系统、也可以重启Linux系统。
命令语法：
/sbin/shutdown [-t c] [-arkhncfFHP] time [warning-message]
命令参数：
参数长参数描叙
-a U /etc/shutdown.allow.
-c中断关机：当执⾏"shutdown -h 12:00"指令时，只要按+键就可以中断关机的指令
-f重新启动时不进⾏磁盘检测（fsck）
-F重新启动时进⾏磁盘检测（fsck）
-h关闭电源
-k模拟关机（不是真的关机），只是向登录者发送警告信息出去！
-n不调⽤init进程进⾏关机，⽽是强⾏关机
-r关闭系统然后重新启动，类似于Windows平台restart
橄榄枝是什么意思-t延迟关机的时间
-w仅做测试，并不真的将系统重新开机，只会把重开机的数据写⼊/var/log⽬录下的wtmp记录⽂
件
--help显⽰命令在线帮助高考志愿填报
使⽤⽰例：
1: 查看reboot命令的帮助信息
[root@db-rver ~]# shutdown --help
shutdown: invalid option -- -
Usage: shutdown [-akrhHPfnc] [-t cs] time [warning message]
-a: u /etc/shutdown.allow
-k: don't really shutdown, only warn.
-r: reboot after shutdown.
-h: halt after shutdown.
-P: halt action is to turn off power.
-H: halt action is to just halt.
-f: do a 'fast' reboot (skip fsck).
-F: Force fsck on reboot.
-n: do not go through "init" but go down real fast.
-
c: cancel a running shutdown.
-t cs: delay between warning and kill signal.
** the "time" argument is mandatory! (try "now") **
[root@db-rver ~]#
[root@db-rver ~]# shutdown -h now
Broadcast message from root (pts/1) (Sat Jan 10 18:51:34 2015):
The system is going down for system halt NOW!
3：系统2分钟后重新启动，其中+m表⽰⼏分钟后关机或开机。苟三权
[root@db-rver ~]# shutdown -r +2
Broadcast message from root (pts/2) (Sat Jan 10 19:56:00 2015):
施工组织设计范本
The system is going DOWN for reboot in 2 minutes!
4：设置系统在那个时间点关机
[root@db-rver ~]# shutdown -h 12:30铝元素
或
[root@db-rver ~]# shutdown -h 12:30 &
[1] 4578
最好是使⽤命令&将关机命令⾄于后台处理。不影响当前其它操作。
设置多久时间后执⾏shutdown命令。时间参数有hh：mm或+m两种模式。hh：mm格式表⽰在⼏点⼏分执⾏shutdown命令。例如“shutdown 10：45”表⽰将在10：45执⾏shutdown.+m表⽰m分钟后执⾏shutdown.⽐较特别的⽤法是以now表⽰⽴即执⾏shutdown. 值得注意的是这部分参数不能省略。另外，需要注意如果现在已经22:30，你执⾏了shutdown -h 22:00 & 那么第⼆天才会关机。
5：将前⼀个shutdown命令取消息
如下所⽰，执⾏了下⾯命令让Linux在12:30关机，但是如果发现这个时间点不合适，那么可以使⽤CTRL+C取消
[root@db-rver ~]# shutdown -h 12:30
Shutdown cancelled.
[root@db-rver ~]#
也可以在另外⼀个命令窗⼝执⾏下⾯命令
[root@db-rver ~]# shutdown -c
6：向所有登录的⽤户发出信息
[root@db-rver ~]# shutdown -k "now"
Broadcast message from root (pts/2) (Sat Jan 10 20:09:14 2015):
The system is going down to maintenance mode NOW!
Shutdown cancelled.
另外登录的会话窗⼝会收到如下信息
[root@db-rver ~]#手工教案
[root@db-rver ~]#
Broadcast message from root (pts/2) (Sat Jan 10 20:11:34 2015):
The system is going down to maintenance mode NOW!
⼀般使⽤下⾯语法，如下所⽰
[root@db-rver ~]# shutdown -k now "The Server will shutdown now" Broadcast message from root (pts/1) (Sat Jan 10 20:14:54 2015):
The Server will shutdown now
The system is going down to maintenance mode NOW!
Shutdown cancelled.
7：重新启动时不进⾏磁盘检测
读后感结尾[root@db-rver ~]# shutdown -fr now
朝鲜是韩国吗Broadcast message from root (pts/1) (Sat Jan 10 20:23:59 2015):
The system is going down for reboot NOW!
8：在多少秒后关闭系统并给⽤户发送提⽰信息
[root@db-rver ~]# shutdown -t 10 -h now "System will shutdown 10 ncond later" Broadcast message from root (pts/1) (Sat Jan 10 20:33:36 2015):
System will shutdown 10 ncond later
The system is going down for system halt NOW!
