An Acronym for Advanced Configuration and Power Interface.

The newer interface for changing devices' power status (eg on standby, hibernating, etc); supersedes APM.

Some example uses:

• spinning down idle hard drives,
• telling a monitor to go into lower power mode (but different from DPMS for going into standby)
• making a machine go into standby or complete hibernation

Many newer laptops use ACPI exclusively without support for APM. Linux kernel 2.4.x had some support for ACPI, but kernel 2.6 should have much better support.

There is all kinds of interesting information inside /proc/acpi For example:

Is my Laptop Lid open? : cat /proc/acpi/button/lid/LID/state

The State of your laptops battery : cat /proc/acpi/battery/BAT1/state

acpi command

This can tell you how much charge is left in your laptop battery and how long until it is depleted.

Example Output:

• Battery 1: discharging, 96%, 02:34:16 remaining

See also: the ACPI specification