查看是否安装rtcwake
whereis rtcwake rtcwake: /usr/sbin/rtcwake /usr/share/man/man8/rtcwake.8.gz
查看rtcwake帮助
rtcwake --help Usage: rtcwake [options] Options: -d, --device <device> select rtc device (rtc0|rtc1|...) -n, --dry-run does everything, but suspend -l, --local RTC uses local timezone -m, --mode <mode> standby|mem|... sleep mode -s, --seconds <seconds> seconds to sleep -t, --time <time_t> time to wake -u, --utc RTC uses UTC -v, --verbose verbose messages -h, --help display this help and exit -V, --version output version information and exit For more details see rtcwake(8).
使用方法
standby
普通待机模式，为默认选项，对应ACPI state S1
mem
待机到内存，即内存之外把其他设备都进入低功耗模式，对应ACPI state S3
disk
待机到硬盘，即休眠，把电脑的当前状态保存到硬盘，几乎不消耗外部电源，对应ACPI state S4
off
通过调用系统的关机命令来休眠， 对应ACPI state S5
可以通过以下命令查阅当前系统支持的休眠模式
cat /sys/power/state standby mem disk
执行该命令的时候需要root权限
1. 系统休眠后20seconds唤醒，加-v选项可以看到更多的打印信息
sudo rtcwake -v -s 20 -m mem 或 sudo rtcwake -v -s 20 -m standby
打印信息:
rtcwake -v -s 20 -m mem Using UTC time. delta = 0 tzone = 0 tzname = UTC systime = 1393296617, (UTC) Tue Feb 25 02:50:17 2014 rtctime = 1393296617, (UTC) Tue Feb 25 02:50:17 2014 alarm 0, sys_time 1393296617, rtc_time 1393296617, seconds 20 rtcwake: wakeup from "mem" using /dev/rtc0 at Tue Feb 25 02:50:38 2014 suspend mode: mem; suspending system
2. 系统在指定的时间醒来
rtcwake -v -t `date -d 10:53 +%s` -m mem Using UTC time. delta = 0 tzone = 0 tzname = UTC systime = 1393296754, (UTC) Tue Feb 25 02:52:34 2014 rtctime = 1393296754, (UTC) Tue Feb 25 02:52:34 2014 alarm 1393296780, sys_time 1393296754, rtc_time 1393296754, seconds 0 rtcwake: wakeup from "mem" using /dev/rtc0 at Tue Feb 25 02:53:00 2014 suspend mode: mem; suspending system
rtcwake -v -t `date -d 10:54 +%s` -m standby Using UTC time. delta = 0 tzone = 0 tzname = UTC systime = 1393296794, (UTC) Tue Feb 25 02:53:14 2014 rtctime = 1393296794, (UTC) Tue Feb 25 02:53:14 2014 alarm 1393296840, sys_time 1393296794, rtc_time 1393296794, seconds 0 rtcwake: wakeup from "standby" using /dev/rtc0 at Tue Feb 25 02:54:00 2014 suspend mode: standby; suspending system
如果发现systime 和rtctime时间不一致，需要利用hwclock进行调整。
原文链接：https://blog.csdn.net/bulreed/article/details/19907691