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APM(8) System Manager's Manual APM(8)


apm, zzzAdvanced Power Management control program


apm [-abdlmSsvz] [-f sockname]

zzz [-Sz] [-f sockname]


The apm program communicates with the Advanced Power Management (APM) daemon, apmd(8), making requests of the current power status or placing the system either into suspend or stand-by state. The apm tool is only installed on supported platforms.

With no flags, apm displays the current power management state in verbose form.

Available command-line flags are:

Display the external charger (A/C 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.
Do not communicate with the APM daemon; attempt instead to manipulate the APM control device directly.
-f sockname
Set the name of the socket via which to contact apmd(8) to sockname.
Display the estimated battery lifetime in percent.
Display the estimated battery lifetime in minutes.
Put the system into stand-by (light sleep) mode.
Display if power management is enabled.
Request more verbose description of the displayed states.
Put the system into suspend (deep sleep) mode.

The zzz variant of this command is an alternative for suspending the system. With no arguments, zzz places the system into suspend mode. The command line flags serve the same purpose as for the apm variant of this command.

This command does not wait for positive confirmation that the requested mode has been entered; to do so would mean the command does not return until the system resumes from its sleep state.


/var/run/apmdev is the default UNIX-domain socket used for communication with apmd(8). The -f flag may be used to specify an alternate socket name. The protection modes on this socket govern which users may access the APM functions.

/dev/apmctl is the control device which is used when the -d flag is specified; it must be writable for the -d flag to work successfully. /dev/apm is the status device used when the socket is not accessible; it must be readable to provide current APM status.


acpi(4), apm(4), apmd(8)

Intel Corporation and Microsoft Corporation, Advanced Power Management (APM) BIOS Interface Specification, Revision 1.2, February 1996.


The apm command appeared in NetBSD 1.3.

The APM specification first appeared in 1992. The last update to the standard was made in 1996 - the same year when it was superceded by the ACPI 1.0 standard. Thereafter power management on IBM-compatible personal computers has relied on ACPI, implemented in NetBSD by the acpi(4) subsystem. The acpi(4) provides an emulation layer for the legacy apm.

March 20, 2010 NetBSD 7.0