группа команд, которая в первую очередь работает со всеми файловыми системами (command group that primarily does work on the whole filesystems)
Описание (Description)
btrfs filesystem
is used to perform several whole filesystem
level tasks, including all the regular filesystem operations like
resizing, space stats, label setting/getting, and
defragmentation. There are other whole filesystem tasks like
scrub or balance that are grouped in separate commands.