146 lines
5.7 KiB
Plaintext
146 lines
5.7 KiB
Plaintext
//po4a: entry man manual
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= rtcwake(8)
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:doctype: manpage
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:man manual: System Administration
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:man source: util-linux {release-version}
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:page-layout: base
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:command: rtcwake
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== NAME
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rtcwake - enter a system sleep state until specified wakeup time
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== SYNOPSIS
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*rtcwake* [options] [*-d* _device_] [*-m* _standby_mode_] {*-s* _seconds_|*-t* _time_t_}
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== DESCRIPTION
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This program is used to enter a system sleep state and to automatically wake from it at a specified time.
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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.
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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 analogues of BIOS, APM, or ACPI.
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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.
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Note that alarm functionality depends on hardware; not every RTC is able to setup an alarm up to 24 hours in the future.
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The suspend setup may be interrupted by active hardware; for example wireless USB input devices that continue to send events for some fraction of a second after the return key is pressed. *rtcwake* tries to avoid this problem and it waits to terminal to settle down before entering a system sleep.
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== OPTIONS
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*-A*, *--adjfile* _file_::
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Specify an alternative path to the adjust file.
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*-a*, *--auto*::
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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.
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*--date* _timestamp_::
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Set the wakeup time to the value of the timestamp. Format of the timestamp can be any of the following:
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[cols=",",]
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|===
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|YYYYMMDDhhmmss |
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|YYYY-MM-DD hh:mm:ss |
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|YYYY-MM-DD hh:mm |(seconds will be set to 00)
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|YYYY-MM-DD |(time will be set to 00:00:00)
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|hh:mm:ss |(date will be set to today)
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|hh:mm |(date will be set to today, seconds to 00)
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|tomorrow |(time is set to 00:00:00)
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|+5min |
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|===
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*-d*, *--device* _device_::
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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.
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*-l*, *--local*::
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Assume that the hardware clock is set to local time, regardless of the contents of the _adjtime_ file.
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*--list-modes*::
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List available *--mode* option arguments.
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*-m*, *--mode* _mode_::
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Go into the given standby state. Valid values for _mode_ are:
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*standby*;;
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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.
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*freeze*;;
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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.)
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*mem*;;
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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.
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*disk*;;
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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.
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*off*;;
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ACPI state S5 (Poweroff). This is done by calling '/sbin/shutdown'. Not officially supported by ACPI, but it usually works.
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*no*;;
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Don't suspend, only set the RTC wakeup time.
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*on*;;
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Don't suspend, but read the RTC device until an alarm time appears. This mode is useful for debugging.
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*disable*;;
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Disable a previously set alarm.
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*show*;;
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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".
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*-n*, *--dry-run*::
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This option does everything apart from actually setting up the alarm, suspending the system, or waiting for the alarm.
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*-s*, *--seconds* _seconds_::
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Set the wakeup time to _seconds_ in the future from now.
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*-t*, *--time* _time_t_::
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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_.
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*-u*, *--utc*::
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Assume that the hardware clock is set to UTC (Universal Time Coordinated), regardless of the contents of the _adjtime_ file.
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*-v*, *--verbose*::
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Be verbose.
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*-V*, *--version*::
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Display version information and exit.
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*-h*, *--help*::
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Display help text and exit.
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== NOTES
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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.
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== FILES
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_{ADJTIME_PATH}_
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== HISTORY
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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.
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== AUTHORS
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The program was written by mailto:dbrownell@users.sourceforge.net[David Brownell] and improved by mailto:bwalle@suse.de[Bernhard Walle].
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== COPYRIGHT
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This is free software. You may redistribute copies of it under the terms of the link:http://www.gnu.org/licenses/gpl.html[GNU General Public License]. There is NO WARRANTY, to the extent permitted by law.
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== SEE ALSO
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*hwclock*(8),
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*date*(1)
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include::man-common/bugreports.adoc[]
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include::man-common/footer.adoc[]
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ifdef::translation[]
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include::man-common/translation.adoc[]
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endif::[]
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