pm-utils, or how to manage power options from the console

Today, most of the personnel own portable computing equipment, such as "notebooks" or "netbooks", and their Achilles heel is the energy management, since allowing the equipment to consume more than necessary, shortens the autonomy of the batteries.

In graphical environments, there are almost no operating systems, and even more so under GNU / Linux, that do not have a graphical daemon that allows managing the different options that can be presented with a mouse click, such as suspend, hibernate or go to low mode. consumption.

But it is rare that one needs to do it from the console.

Why is this relevant? Well, recently I received as a "lag" a netbook whose owner did not use it anymore because its operating system had become too heavy, making the machine almost unusable. He told me about XP and a number 7, but they are things that I did not understand. 🙂

Well, the gadget is currently running a Debian 7 "wheezy" with an OpenBox screen manager, configured to the minimum expression, but this minimal expression made me investigate how to use the benefits of advanced power management from the console, since in In order to minimize resource consumption, I avoided installing anything that could be done from the console.

And there I came across pm-utils.

pm-utils

pm-utils, as stated on its page http://pm-utils.freedesktop.org, "is a small collection of commands that allow HAL to suspend and resume."

Just in case,
H (High): maximum utilization of the cooling system.
A (Auto): automatic temperature regulation system.
L (Low): minimum use of the cooling system. When it exceeds a certain limit, it goes into automatic mode.

The package installs automatically with any Debian base system, and has the following commands:

/ usr / bin / pm-is-supported- Used to determine which power saving modes are supported by the system.

/ usr / sbin / pm-powersave: activates or deactivates the energy saving mode, changing it to «L»

/ usr / sbin / pm-suspend: suspends operations in memory and puts the system to the lowest possible power.

/ usr / sbin / pm-hibernate- Hibernate the system by downloading all data from memory to the hard disk.

/ usr / sbin / pm-suspend-hybrid- Puts the system into a state equal to hibernation, but in memory. That is, its recovery is similar to sleep, faster than normal hibernation, but if the battery runs out, it remains in hibernate state, without losing data, as would happen with a sleep. It's the best of both schemes, and my favorite.

The utility package has excellent documentation in English, and configuration directories /etc/pm/config.d, /etc/pm/sleep.d and /usr/lib/pm-utils/sleep.d that allow customizing the behavior of the system to suit everyone.