hdparm:tldr:12384

The command sudo hdparm -B /dev/${device} is used to adjust the Advanced Power Management (APM) settings for a specific device on a Linux system.

Here's a breakdown of each part of the command:

• sudo: This is used to run the command as a superuser or root. It provides administrative privileges required to change the APM settings.

• hdparm: It is a command-line utility that allows you to interact with and control ATA/SATA hard disk drives and Solid-State Drives (SSDs).

• -B: This flag is used to specify the APM level. APM is a feature that allows power management of a hard drive to reduce energy consumption and noise. The -B flag is followed by a parameter that determines the APM level, which ranges from 1 to 255. Lower values generally mean more aggressive power management, while larger values provide better performance. A value of 255 disables APM entirely.

• /dev/${device}: This is a placeholder that represents the device name you want to adjust the APM settings for. You need to replace ${device} with the actual device name, such as 'sda' for the first hard drive or 'sdb' for the second one. This refers to the device file in the /dev directory that represents the specific disk or drive.

To summarize, the command allows you to use hdparm to set the APM level for a specific device on your Linux system by adjusting the -B flag and specifying the device using /dev/${device}.