apm

Install a package from or a theme from

$ apm install [package]

$ apm remove [package]

$ apm upgrade [package]

apm [options]

-V
    Display verbose information, often including daemon version if apmd is running.

-a
    Display AC line status (online/offline).

-b
    Display battery status (e.g., discharging, charged, critical, low).

-c
    Display battery percentage remaining.

-l
    Display low battery warning status.

-m
    Display estimated remaining battery time in minutes.

-p
    Put the system into the APM standby state (low power, often CPU stopped).

-s
    Display overall power status, including AC line, battery state, and APM capabilities.

-S
    Put the system into the APM suspend state (deeper sleep than standby, often saving to RAM).

-v
    Display version information of the apm utility.

-W
    Wait for APM events. This option is primarily used by the apmd daemon, not typically for interactive use.

The apm command is a utility for interacting with the system's Advanced Power Management (APM) BIOS interface. APM was an earlier standard for power management on x86 computers, preceding the more comprehensive Advanced Configuration and Power Interface (ACPI). This command allows users to query the APM BIOS for information such as battery status (charge, remaining time), AC adapter status, and power management states (e.g., suspend, standby). It reads information typically exposed through the /proc/apm file system interface, which is populated by the apm_bios kernel module. While largely superseded by ACPI on modern hardware, apm can still be relevant for older laptops, some embedded systems, or virtual machines that emulate APM. It provides a textual interface to basic power management functions.

The apm command relies on the BIOS-level Advanced Power Management (APM) interface, which has been largely superseded by the Advanced Configuration and Power Interface (ACPI) on modern computers. Consequently, it may not function correctly or at all on newer hardware, where power management is handled exclusively by ACPI. The kernel must have apm_bios support compiled in or loaded as a module, and the BIOS must expose APM functionality. Its power management actions (suspend/standby) are often less reliable or functional compared to ACPI-based methods.

For the apm command to function, the Linux kernel must have the CONFIG_APM and CONFIG_APM_BIOS options enabled, typically through the apm_bios module. The command interacts with the kernel via the /proc/apm pseudo-filesystem, which exposes the APM BIOS state.

The Advanced Power Management (APM) standard was developed by Intel and Microsoft in 1992 as a BIOS-level interface for power management on x86 PCs. The apm command and associated daemon (apmd) were created in the Linux environment to provide userspace access to these BIOS functions. Its peak usage was in the mid to late 1990s and early 2000s, especially on laptops. With the widespread adoption of ACPI (starting around 1996 and becoming standard by the early 2000s), APM gradually became obsolete. While still part of the Linux kernel for backward compatibility, new hardware primarily relies on ACPI.

acpi(1), upower(7), pm-suspend(8), proc(5)