RTCWAKE(8) System Administration RTCWAKE(8)
NAME
rtcwake - enter a system sleep state until specified wakeup time
SYNOPSIS
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.
This uses cross-platform Linux interfaces to enter a system sleep state, and leave it no
later than a specified time. It uses any RTC framework driver that supports standard
driver model wakeup flags.
This is normally used like the old apmsleep utility, to wake from a suspend state like
ACPI S1 (standby) or S3 (suspend-to-RAM). Most platforms can implement those without ana‐
logues of BIOS, APM, or ACPI.
On some systems, this can also be used like nvram-wakeup, waking from states like ACPI S4
(suspend to disk). Not all systems have persistent media that are appropriate for such
suspend modes.
OPTIONS
-A, --adjfile file
Specify an alternative path to the adjust file.
-a, --auto
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.
--date timestamp
Set the wakeup time to the value of the timestamp. Format of the timestmap 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
-d, --device device
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.
-l, --local
Assume that the hardware clock is set to local time, regardless of the contents of
the adjtime file.
--list-modes
List available --mode option arguments.
-m, --mode mode
Go into the given standby state. Valid values for mode are:
standby
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.
freeze The processes are frozen, all the devices are suspended and all the proces‐
sors 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.)
mem 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 mem‐
ory, which is placed in self-refresh mode to retain its contents.
disk ACPI state S4 (Suspend-to-disk). This state offers the greatest power sav‐
ings, 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.
off ACPI state S5 (Poweroff). This is done by calling '/sbin/shutdown'. Not
officially supported by ACPI, but it usually works.
no Don't suspend, only set the RTC wakeup time.
on Don't suspend, but read the RTC device until an alarm time appears. This
mode is useful for debugging.
disable
Disable a previously set alarm.
show Print alarm information in format: "alarm: off|on