btrfs-device:tldr:8b29c

This command is used to add one or more block devices to an existing Btrfs filesystem using the 'btrfs device add' command with elevated privileges (using 'sudo').

Here's the breakdown of the command:

• 'sudo': This keyword is used to execute the following command with administrative or root privileges.
• 'btrfs': It is the command-line utility for managing Btrfs filesystems.
• 'device add': This is the specific command within 'btrfs' used to add a new block device to a Btrfs filesystem.
• '${path-to-block_device1}': This is the placeholder for the path or location of the first block device that you want to add. You need to provide the actual path to the block device here, like /dev/sdb1.
• '[${path-to-block_device2}]': This part is optional. It represents the path or location of a second block device that you want to add. You can either include or exclude it depending on whether you want to add a single device or multiple devices at once.
• '${path-to-btrfs_filesystem}': This is the placeholder for the path to the existing Btrfs filesystem where you want to add the block device(s). You need to provide the actual path to the Btrfs filesystem here, like /mnt/btrfs.

In summary, this command allows you to add one or more block devices to an existing Btrfs filesystem by specifying the paths to the block devices and the Btrfs filesystem.