apm
Manage Advanced Power Management (APM)
TLDR
Install a package from
Remove a package/theme
Upgrade a package/theme
SYNOPSIS
apm [-S | -s | -l | -q | -e | -d | -v | -V]
PARAMETERS
-S
Engage APM suspend state
-s
Engage APM standby state
-l
Engage APM suspend state and lock console (uses vlock if available)
-q
Query and display APM status
-e
Enable APM
-d
Disable APM
-v
Verbose output
-V
Print version information
DESCRIPTION
The apm command is a utility for interacting with the Advanced Power Management (APM) subsystem on Linux systems, primarily laptops from the 1990s and early 2000s. APM, developed by Intel, Microsoft, and Phoenix Technologies, allows software to monitor battery levels, AC adapter status, and manage power states like standby or suspend.
Running apm without arguments queries and displays key information: battery charge percentage, time remaining, AC line status (online/offline), battery status (charging/high/low/critical), and the suspend state (enabled/disabled/engaged). Options enable control actions such as suspending the system or enabling/disabling APM.
This tool relies on the APM kernel driver (drivers/char/apm_bios.c) and communicates via /proc/apm or /dev/apm_bios. Output resembles:
APM BIOS version 1.2
APM flags 0x07
AC line status: on-line
Battery status: charging, 85%
Estimated battery life: 2:15 (145 min)
While useful for legacy hardware, apm is largely obsolete on modern systems using ACPI for finer power control. Install via apm package (e.g., in Debian: apt install apmd).
CAVEATS
Deprecated on modern hardware; replaced by ACPI. May fail without APM BIOS support or kernel driver. Not for servers or new laptops. Check /proc/acpi/battery instead.
SAMPLE OUTPUT
AC line status: on-line
Battery status: high (85%)
Estimated battery life: 2:15
Interprets levels: high (>75%), low (<25%), critical (<10%).
INSTALLATION NOTE
Part of apmd package. Debian/Ubuntu: apt install apmd; Fedora: dnf install apmd.
HISTORY
APM introduced 1992 (Intel/MS/Phoenix). Linux support from 1994 (Geert Uytterhoeven). apm command debuted ~1995 in apmd package. Largely phased out post-2004 with ACPI 2.0 adoption.
