立即重启计算机 echo "b" > /proc/sysrq-trigger
立即关闭计算机 echo "o" > /proc/sysrq-trigger
导出内存分配的信息 echo "m" > proc/sysrq-trigger (可以用/var/log/message查看)Outputs memory statistics to the console
导出当前CPU寄存器信息和标志位的信息 echo "p" > proc/sysrq-trigger (outputs all flags and registers to the console)
导出线程状态信息 echo "t" > proc/sysrq-trigger (outputs a list of processes to the console)
故意让系统崩溃 echo "c" > proc/sysrq-trigger (crashes the system without first unmounting file systems or syncing disks attached to the system)
立即重新挂载所有的文件系统 echo "s" > proc/sysrq-trigger (attempts to sync disks attached to the system)
立即重新挂载所有的文件系统为只读 echo "u" > proc/sysrq-trigger (attempts to unmount and remount all file systems as read-only)
此外，还有两个类似于强制注销的功能
e ---- kills all processes except init using SIGTERM
i ---- kills all processes except init using SIGKILL
/proc/cmdline
dmesg | grep -i crash;
cat /proc/sys/kernel/sysrq
sysctl -w kernel.sysrq = 1;
echo c > /proc/sysrq-trigger
类linux系统/proc/sysrq-trigger文件功能作用
原文：http://www.cnblogs.com/ruiy/p/4460068.html