pm-powersave

pm-powersave [options]

--help
    Display help message and exit.

--version
    Display version information and exit.

The `pm-powersave` command is a utility used to enable or disable power saving features on a Linux system. It is part of the `pm-utils` package, which provides a framework for managing system power states. When executed without arguments, `pm-powersave` typically enables power saving, attempting to minimize energy consumption. It achieves this by adjusting various system parameters related to CPU frequency scaling, hard drive spindown, display blanking, and more.

The effects of `pm-powersave` are usually noticeable, potentially impacting performance, especially with CPU intensive tasks. It primarily configures devices to their power-saving settings. It's beneficial for extending battery life on laptops or reducing overall power usage on desktop systems, but may cause delays or decreased responsiveness while enabled.

Note that modern distributions utilize systemd and its power management capabilities as the primary way of handling power consumption. Therefore, the pm-utils package and `pm-powersave` have become less relevant as they are deprecated in some distros.

This command has been largely superseded by systemd power management. Its functionality might be limited or unavailable on systems using modern power management frameworks. Use with caution, and consider systemd equivalents if available.

The `pm-utils` tools, including `pm-powersave`, often relied on configuration files located in `/etc/pm/config.d/` and `/usr/lib/pm-utils/`. These files allowed customization of the power management behavior, for example, to configure which devices should be suspended or hibernated, and how.

The `pm-utils` framework executes scripts in the `/usr/lib/pm-utils/power.d/` directory to manage power transitions. `pm-powersave` would utilize these scripts to configure the system's power saving settings.

The `pm-powersave` command was developed as part of the `pm-utils` package, aiming to provide a standardized way to manage power states across different Linux distributions. Before `pm-utils`, power management was handled inconsistently, leading to complexities and difficulties in ensuring effective power saving across various hardware configurations. The `pm-utils` package, including `pm-powersave`, provided a more unified approach.

However, with the rise of `systemd`, which includes comprehensive power management capabilities, the importance of `pm-utils` has diminished. systemd integrates power management more deeply into the core system, offering a more robust and consistent solution. Therefore, modern distributions are moving away from `pm-utils` in favor of `systemd`'s power management features.

pm-suspend(8), pm-hibernate(8), systemctl(1)