Advanced Power Management control
apm communicates with the Advanced Power
Management daemon, apmd(8), making requests of it for current power status or to place
the system into a suspend or stand-by state. With no flags,
apm displays the current power management state in
The options are as follows:
- Switch to automatic performance adjustment mode (the default).
- Display the external charger (AC) status. 0 means disconnected, 1 means connected, 2 means backup power source, and 255 means unknown.
- Display the battery status. 0 means high, 1 means low, 2 means critical, 3 means charging, 4 means absent, and 255 means unknown.
- Set the name of the socket via which to contact apmd(8) to sockname.
- Switch to manual performance adjustment mode, setting hw.setperf to 100.
- Switch to manual performance adjustment mode, setting hw.setperf to 0.
- Display the estimated battery lifetime, in percent.
- Display the estimated battery lifetime, in minutes. If charging, the estimated time to fully charge is displayed instead.
- Display the performance adjustment mode. 0 means manual mode. 1 means automatic mode.
- Put the system into stand-by (light sleep) state.
- Request more verbose description of the displayed states.
- Put the system into hibernation. System memory is saved to disk (swap space) and the machine is powered down. For machines supporting the acpi(4) style hibernate functionality, on resume a full kernel boot will occur, followed by the reading of the saved memory image. The image will then be unpacked and the system resumed at the point immediately after the hibernation request.
- Put the system into suspend (deep sleep) state.
commands are shortcuts for suspending and hibernating the system,
respectively. With no arguments, they are placed into their respective
states. The command line flags serve the same purpose as for
These commands do not wait for positive confirmation that the requested state has been entered; to do so would mean the command does not return until the system resumes from its sleep state.
Each system provides methods for waking from suspend or hibernate. For those machines supporting acpi(4) style suspend/resume (or hibernate/unhibernate) semantics, the wakeup devices for each sleep state are printed during system boot in dmesg(8).
The system will attempt to provide as much feedback as is possible on the specific hardware being suspended/resumed. This includes setting system LEDs or other indicators to illustrate progress throughout the suspend/resume (or hibernate/unhibernate) process. Such feedback is machine-dependent.
- The default UNIX-domain socket for communicating
with apmd(8). The
-fflag may be used to specify an alternate socket name. The protection modes on this socket govern which users may access the APM functions.
Advanced Power Management (APM) BIOS Interface Specification (revision 1.2), Intel Corporation and Microsoft Corporation
apm command appeared in
NetBSD 1.3; OpenBSD support
was added in OpenBSD 1.2.