[options] cp | ss [device] checkpoint-number ...
is a utility to change the mode of the given checkpoints for the NILFS2
file system found in device.
changes checkpoints to snapshots, or vice versa. The target
checkpoints are specified with one or more checkpoint numbers. When
device is omitted, it tries to find a NILFS2 file system from
This command is valid only for mounted NILFS2 file systems, and
will fail if the device has no active mounts.