APMSLEEP(1)                                                        APMSLEEP(1)

       apmsleep - go into suspend or standby mode and wake-up later

       apmsleep  [-sSnwhVd] [--suspend] [--standby] [--noapm] [--wait] [--pre-
       cise] [--help]  [--version] [--debug] [+]hh:mm

       Some computers, especially laptops, can wake-up from a  low-power  sus-
       pend  to  DRAM mode using the Real-time-clock (RTC) chip.  Apmsleep can
       be used to set the alarm time in the RTC and  to  go  into  suspend  or
       standby mode. An interrupt from the RTC causes the computer to wake-up.
       The program detects this event, by waiting for a  leap  in  the  kernel
       time  and  terminates  successfully.  If no time leap occurs within one
       minute, or something goes wrong, the exit value will be non-zero.

       The wake-up time can be specified in two formats:

       +hh:mm specifies a relative offset to the current  time.  The  computer
       will  suspend for exactly hh hours and mm minutes plus a few seconds to
       wake up.  On some laptops, the timing is not completely accurate so  it
       may be a few minutes (or more?) late.

       hh:mm  specifies absolute local time in 24-hour format. The time stored
       in the RTC is not important.  You may change the time zone  used,  with
       the  TZ  environment  variable  as  usual.  Daylight saving time is not
       obeyed in this version, but might be in a future release.  WARNING:  Do
       not  close  cover  of laptop after suspending the laptop with apmsleep.
       Most laptops overheat when running with closed cover.

       Energy conservation with APM is little for a desktop.  Turning  of  the
       screen  will  save  1/2, going into standby with drives turned off will
       save another 1/6th of the current.

       -V, --version
              Print the apmsleep program version and exit immediately.

       -s, --suspend
              Put the machine into suspend mode if possible (default).  On  my
              laptop, suspend mode turns off everything except the memory.

       -S, --standby
              Put  the  machine  into  standby mode if possible. On my laptop,
              standby mode turns off screen, hard disk, and CPU.

       -w, --wait
              Wait indefinitely for the time leap.

       -p, --precise
              Wait for alarm time to match actual time. Do not wait  for  time
              leap.  This might be useful even without APM.

       -n, --noapm
              Do  not  call  apm  bios to suspend computer, just set the alarm
              clock and wait for time leap indefinitely.

       -d, --debug
              Print some information about what is going on.

       Kernel The special character device /dev/rtc must exist and  the  Linux
              kernel   needs   to   be  compiled  with  APM  and  RTC  support
              (CONFIG_RTC, and relevant CONFIG_APM* options).

       BIOS   The computer must have the 'suspend to RAM' feature  enabled  in
              the  BIOS; 'suspend to Disk' will not work, because the computer
              is turned off completely. You do not need to  enable  the  ALARM
              timer, it will be activated by apmsleep. On some boards, you can
              configure which interrupts can be used  to  awake  from  suspend
              mode. If you have such a board, you might want to make sure that
              keyboard (IRQ 1) and RTC (IRQ 8) are among those interrupts.  If
              your  computer  does  not wake up, try to enable 'modem ring' in
              the BIOS, even if you do not have a modem.

              The program must be run as root or have the SUID  attribute  set
              (see chmod(1)).

       Apmsleep  cannot detect which event terminated the suspension. Possible
       events are: keyboard or mouse activity, modem ring, alarm from RTC, any
       other  interrupt.  Sometimes,  the  time  leap is not detected properly
       (causing a wrong exit value).

       Should use APM BIOS calls to set alarm clock (not yet supported by ker-

       This  program was tested on a Winbook XL laptop (Pentium) only.  It may
       not function on your hardware.

       Written by Peter Englmaier (  and  may  be  freely  dis-
       tributed  under  the terms of the GNU General Public License.  The code
       is based on Paul Gortmacher's RTC test/example program.  There is ABSO-
       LUTELY  NO  WARRANTY for this program.  The current maintainer is Peter

       xapm(1), apmd(8),rtc.txt(Linux Kernel Documentation)

APM                    sleep in APM suspend/standby mode           APMSLEEP(1)