NAME
rtcwake - enter a system sleep state until specified wakeup timeSYNOPSIS
rtcwake [options] [-d device] [-m standby_mode] { -s seconds|-t time_t}DESCRIPTION
This program is used to enter a system sleep state and to automatically wake from it at a specified time.OPTIONS
-A, --adjfile fileSpecify an alternative path to the adjust
file.
Read the clock mode (whether the hardware
clock is set to UTC or local time) from the adjtime file, where
hwclock(8) stores that information. This is the default.
Set the wakeup time to the value of the
timestamp. Format of the timestamp can be any of the following:
YYYYMMDDhhmmss | |
YYYY-MM-DD hh:mm:ss | |
YYYY-MM-DD hh:mm | (seconds will be set to 00) |
YYYY-MM-DD | (time will be set to 00:00:00) |
hh:mm:ss | (date will be set to today) |
hh:mm | (date will be set to today, seconds to 00) |
tomorrow | (time is set to 00:00:00) |
+5min |
Use the specified device instead of
rtc0 as realtime clock. This option is only relevant if your system has
more than one RTC. You may specify rtc1, rtc2, ... here.
Assume that the hardware clock is set to local
time, regardless of the contents of the adjtime file.
List available --mode option
arguments.
Go into the given standby state. Valid values
for mode are:
standby
freeze
mem
disk
off
no
on
disable
show
ACPI state S1. This state offers minimal,
though real, power savings, while providing a very low-latency transition back
to a working system. This is the default mode.
The processes are frozen, all the devices are
suspended and all the processors idled. This state is a general state that
does not need any platform-specific support, but it saves less power than
Suspend-to-RAM, because the system is still in a running state. (Available
since Linux 3.9.)
ACPI state S3 (Suspend-to-RAM). This state
offers significant power savings as everything in the system is put into a
low-power state, except for memory, which is placed in self-refresh mode to
retain its contents.
ACPI state S4 (Suspend-to-disk). This state
offers the greatest power savings, and can be used even in the absence of
low-level platform support for power management. This state operates similarly
to Suspend-to-RAM, but includes a final step of writing memory contents to
disk.
ACPI state S5 (Poweroff). This is done by
calling '/sbin/shutdown'. Not officially supported by ACPI, but it usually
works.
Don’t suspend, only set the RTC wakeup
time.
Don’t suspend, but read the RTC device
until an alarm time appears. This mode is useful for debugging.
Disable a previously set alarm.
Print alarm information in format:
"alarm: off|on <time>". The time is in ctime() output format,
e.g., "alarm: on Tue Nov 16 04:48:45 2010".
This option does everything apart from
actually setting up the alarm, suspending the system, or waiting for the
alarm.
Set the wakeup time to seconds in the
future from now.
Set the wakeup time to the absolute time
time_t. time_t is the time in seconds since 1970-01-01, 00:00
UTC. Use the date(1) tool to convert between human-readable time and
time_t.
Assume that the hardware clock is set to UTC
(Universal Time Coordinated), regardless of the contents of the adjtime
file.
Be verbose.
Display help text and exit.
Print version and exit.
NOTES
Some PC systems can’t currently exit sleep states such as mem using only the kernel code accessed by this driver. They need help from userspace code to make the framebuffer work again.FILES
/etc/adjtimeHISTORY
The program was posted several times on LKML and other lists before appearing in kernel commit message for Linux 2.6 in the GIT commit 87ac84f42a7a580d0dd72ae31d6a5eb4bfe04c6d.AUTHORS
The program was written by David <[email protected]>Brownell and improved by Bernhard <[email protected]>WalleCOPYRIGHT
This is free software. You may redistribute copies of it under the terms of the GNU General Public License <http://www.gnu.org/licenses/gpl.html>. There is NO WARRANTY, to the extent permitted by law.SEE ALSO
adjtime_config(5), hwclock(8), date(1)REPORTING BUGS
For bug reports, use the issue tracker at <https://github.com/util-linux/util-linux/issues>.AVAILABILITY
The rtcwake command is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.2022-05-11 | util-linux 2.38.1 |