.\" Copyright (c) 2007, SUSE LINUX Products GmbH .\" Bernhard Walle .\" .\" This program is free software; you can redistribute it and/or .\" modify it under the terms of the GNU General Public License .\" as published by the Free Software Foundation; either version 2 .\" of the License, or (at your option) any later version. .\" .\" This program is distributed in the hope that it will be useful, .\" but WITHOUT ANY WARRANTY; without even the implied warranty of .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the .\" GNU General Public License for more details. .\" .\" You should have received a copy of the GNU General Public License .\" along with this program; if not, write to the Free Software .\" Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA .\" 02110-1301, USA. .\" .TH RTCWAKE 8 "July 2007" "util-linux" "System Administration" .SH NAME rtcwake - enter a system sleep state until specified wakeup time .SH SYNOPSIS .B rtcwake .RB [ options ] .RB [ \-d .IR device ] .RB [ \-m .IR standby_mode ] .RB { "\-t \fItime_t\fP" | "\-s \fIseconds\fP" } .SH DESCRIPTION This program is used to enter a system sleep state until specified wakeup time. .PP 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. .PP This is normally used like the old \fBapmsleep\fP 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. .P On some systems, this can also be used like \fBnvram-wakeup\fP, waking from states like ACPI S4 (suspend to disk). Not all systems have persistent media that are appropriate for such suspend modes. .SS Options .TP \fB-v\fP | \fB--verbose\fP Be verbose. .TP \fB-h\fP | \fB--help\fP Display help text and exit. .TP \fB-V\fP | \fB--version\fP Display version information and exit. .TP \fB-n\fP | \fB--dry-run\fP This option does everything apart from actually setting up the alarm, suspending the system, or waiting for the alarm. .TP \fB-A\fP | \fB--adjfile\fP \fIfile\fP Specifies an alternative path to the adjust file. .TP \fB-a\fP | \fB--auto\fP Reads the clock mode (whether the hardware clock is set to UTC or local time) from \fIadjtime\fP file. That's the location where the .BR hwclock (8) stores that information. This is the default. .TP \fB-l\fP | \fB--local\fP Assumes that the hardware clock is set to local time, regardless of the contents of \fIadjtime\fP file. .TP \fB-u\fP | \fB--utc\fP Assumes that the hardware clock is set to UTC (Universal Time Coordinated), regardless of the contents of \fIadjtime\fP file. .TP \fB-d\fP \fIdevice\fP | \fB--device\fP \fIdevice\fP Uses \fIdevice\fP instead of \fIrtc0\fP as realtime clock. This option is only relevant if your system has more than one RTC. You may specify \fIrtc1\fP, \fIrtc2\fP, ... here. .TP \fB-s\fP \fIseconds\fP | \fB--seconds\fP \fIseconds\fP Sets the wakeup time to \fIseconds\fP in future from now. .TP \fB-t\fP \fItime_t\fP | \fB--time\fP \fItime_t\fP Sets the wakeup time to the absolute time \fItime_t\fP. \fItime_t\fP is the time in seconds since 1970-01-01, 00:00 UTC. Use the .BR date (1) tool to convert between human-readable time and \fItime_t\fP. .TP \fB-m\fP \fImode\fP | \fB--mode\fP \fImode\fP Use standby state \fImode\fP. Valid values are: .RS .TP .B 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. .TP .B 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 memory, which is placed in self-refresh mode to retain its contents. .TP .B freeze The processes are frozen, all the devices are suspended and all the processors idles. This state is a general state that does not need any platform specific support, but it saves less power than susepnd to RAM, because the system is still in a running state. (since Linux 3.9) .TP .B disk 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. .TP .B off ACPI state S5 (Poweroff). This is done by calling '/sbin/shutdown'. Not officially supported by ACPI, but usually working. .TP .B no Don't suspend. The rtcwake command sets RTC wakeup time only. .TP .B on Don't suspend, but read RTC device until alarm time appears. This mode is useful for debugging. .TP .B disable Disable previously set alarm. .TP .B show Print alarm information in format: "alarm: off|on