sys-utils/rtcwake.8.in

   1 .\" Copyright (c) 2007, SUSE LINUX Products GmbH
   2 .\"                     Bernhard Walle <bwalle@suse.de>
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  19 .TH RTCWAKE 8 "June 2015" "util-linux" "System Administration"
  20 .SH NAME
  21 rtcwake \- enter a system sleep state until specified wakeup time
  22 .SH SYNOPSIS
  23 .B rtcwake
  24 [options]
  25 .RB [ \-d
  26 .IR device ]
  27 .RB [ \-m
  28 .IR standby_mode ]
  29 .RB { "\-s \fIseconds\fP" | "\-t \fItime_t\fP" }
  30 .SH DESCRIPTION
  31 This program is used to enter a system sleep state and to automatically
  32 wake from it at a specified time.
  33 .PP
  34 This uses cross-platform Linux interfaces to enter a system sleep state, and
  35 leave it no later than a specified time.  It uses any RTC framework driver that
  36 supports standard driver model wakeup flags.
  37 .PP
  38 This is normally used like the old \fBapmsleep\fP utility, to wake from a suspend
  39 state like ACPI S1 (standby) or S3 (suspend-to-RAM).  Most platforms can
  40 implement those without analogues of BIOS, APM, or ACPI.
  41 .PP
  42 On some systems, this can also be used like \fBnvram-wakeup\fP, waking from states
  43 like ACPI S4 (suspend to disk).  Not all systems have persistent media that are
  44 appropriate for such suspend modes.
  45 .PP
  46 Note that alarm functionality depends on hardware; not every RTC is able to setup
  47 an alarm up to 24 hours in the future.
  48 .PP
  49 The suspend setup maybe be interrupted by active hardware; for example wireless USB
  50 input devices that continue to send events for some fraction of a second after the
  51 return key is pressed.
  52 .BR rtcwake
  53 tries to avoid this problem and it waits to terminal to settle down before
  54 entering a system sleep.
  55
  56 .SH OPTIONS
  57 .TP
  58 .BR \-A , " \-\-adjfile " \fIfile
  59 Specify an alternative path to the adjust file.
  60 .TP
  61 .BR \-a , " \-\-auto"
  62 Read the clock mode (whether the hardware clock is set to UTC or local time)
  63 from the \fIadjtime\fP file, where
  64 .BR hwclock (8)
  65 stores that information.  This is the default.
  66 .TP
  67 .BR \-\-date " \fItimestamp"
  68 Set the wakeup time to the value of the timestamp.  Format of the
  69 timestamp can be any of the following:
  70 .TS
  71 tab(|);
  72 left l2 l.
  73 YYYYMMDDhhmmss
  74 YYYY-MM-DD hh:mm:ss
  75 YYYY-MM-DD hh:mm|(seconds will be set to 00)
  76 YYYY-MM-DD|(time will be set to 00:00:00)
  77 hh:mm:ss|(date will be set to today)
  78 hh:mm|(date will be set to today, seconds to 00)
  79 tomorrow|(time is set to 00:00:00)
  80 +5min
  81 .TE
  82 .TP
  83 .BR \-d , " \-\-device " \fIdevice
  84 Use the specified \fIdevice\fP instead of \fBrtc0\fP as realtime clock.
  85 This option is only relevant if your system has more than one RTC.
  86 You may specify \fBrtc1\fP, \fBrtc2\fP, ... here.
  87 .TP
  88 .BR \-l , " \-\-local"
  89 Assume that the hardware clock is set to local time, regardless of the
  90 contents of the \fIadjtime\fP file.
  91 .TP
  92 .B \-\-list\-modes
  93 List available \-\-mode option arguments.
  94 .TP
  95 .BR \-m , " \-\-mode " \fImode
  96 Go into the given standby state.  Valid values for \fImode\fP are:
  97 .RS
  98 .TP
  99 .B standby
 100 ACPI state S1.  This state offers minimal, though real, power savings, while
 101 providing a very low-latency transition back to a working system.  This is the
 102 default mode.
 103 .TP
 104 .B freeze
 105 The processes are frozen, all the devices are suspended and all the processors
 106 idled.  This state is a general state that does not need any platform-specific
 107 support, but it saves less power than Suspend-to-RAM, because the system is
 108 still in a running state.  (Available since Linux 3.9.)
 109 .TP
 110 .B mem
 111 ACPI state S3 (Suspend-to-RAM).  This state offers significant power savings as
 112 everything in the system is put into a low-power state, except for memory,
 113 which is placed in self-refresh mode to retain its contents.
 114 .TP
 115 .B disk
 116 ACPI state S4 (Suspend-to-disk).  This state offers the greatest power savings,
 117 and can be used even in the absence of low-level platform support for power
 118 management.  This state operates similarly to Suspend-to-RAM, but includes a
 119 final step of writing memory contents to disk.
 120 .TP
 121 .B off
 122 ACPI state S5 (Poweroff).  This is done by calling '/sbin/shutdown'.
 123 Not officially supported by ACPI, but it usually works.
 124 .TP
 125 .B no
 126 Don't suspend, only set the RTC wakeup time.
 127 .TP
 128 .B on
 129 Don't suspend, but read the RTC device until an alarm time appears.
 130 This mode is useful for debugging.
 131 .TP
 132 .B disable
 133 Disable a previously set alarm.
 134 .TP
 135 .B show
 136 Print alarm information in format: "alarm: off|on  <time>".
 137 The time is in ctime() output format, e.g. "alarm: on  Tue Nov 16 04:48:45 2010".
 138 .RE
 139 .TP
 140 .BR \-n , " \-\-dry-run"
 141 This option does everything apart from actually setting up the alarm,
 142 suspending the system, or waiting for the alarm.
 143 .TP
 144 .BR \-s , " \-\-seconds " \fIseconds
 145 Set the wakeup time to \fIseconds\fP in the future from now.
 146 .TP
 147 .BR \-t , " \-\-time " \fItime_t
 148 Set the wakeup time to the absolute time \fItime_t\fP.  \fItime_t\fP
 149 is the time in seconds since 1970-01-01, 00:00 UTC.  Use the
 150 .BR date (1)
 151 tool to convert between human-readable time and \fItime_t\fP.
 152 .TP
 153 .BR \-u , " \-\-utc"
 154 Assume that the hardware clock is set to UTC (Universal Time Coordinated),
 155 regardless of the contents of the \fIadjtime\fP file.
 156 .TP
 157 .BR \-v , " \-\-verbose"
 158 Be verbose.
 159 .TP
 160 .BR \-V , " \-\-version"
 161 Display version information and exit.
 162 .TP
 163 .BR \-h , " \-\-help"
 164 Display help text and exit.
 165 .SH NOTES
 166 Some PC systems can't currently exit sleep states such as \fBmem\fP
 167 using only the kernel code accessed by this driver.
 168 They need help from userspace code to make the framebuffer work again.
 169 .SH FILES
 170 .I @ADJTIME_PATH@
 171 .SH HISTORY
 172 The program was posted several times on LKML and other lists
 173 before appearing in kernel commit message for Linux 2.6 in the GIT
 174 commit 87ac84f42a7a580d0dd72ae31d6a5eb4bfe04c6d.
 175 .SH AUTHORS
 176 The program was written by David Brownell <dbrownell@users.sourceforge.net>
 177 and improved by Bernhard Walle <bwalle@suse.de>.
 178 .SH COPYRIGHT
 179 This is free software.  You may redistribute copies of it under the terms
 180 of the GNU General Public License <http://www.gnu.org/licenses/gpl.html>.
 181 There is NO WARRANTY, to the extent permitted by law.
 182 .SH "SEE ALSO"
 183 .BR hwclock (8),
 184 .BR date (1)
 185 .SH AVAILABILITY
 186 The rtcwake command is part of the util-linux package and is available from the
 187 .UR https://\:www.kernel.org\:/pub\:/linux\:/utils\:/util-linux/
 188 Linux Kernel Archive
 189 .UE .