Unknown option: "-8" Unix manual page for mount_apfs. (host=minya system=Darwin)
MOUNT_APFS(8)             BSD System Manager's Manual            MOUNT_APFS(8)

NAME
     mount_apfs -- mount an APFS volume

SYNOPSIS
     mount_apfs [-o options] [-u user] [-g group] special directory
     mount_apfs [-o options] -s snapshot pathname directory

DESCRIPTION
     The mount_apfs command attaches the APFS volume indicated by the device
     special to the global file system namespace at the location indicated by
     directory.  This command is normally executed by diskarbitrationd(8) or
     mount(8) at boot time.

     The special parameter should be the path to an APFS pseudo disk device
     node, such as /dev/disk0s2s1 (which is a volume inside the container
     /dev/disk0s2), which can also be specified as simply disk0s2s1.

     The options are as follows:

     -o options    Options passed to mount(2) are specified with the -o option
                   followed by a comma separated string of options. See the
                   mount(8) man page for possible options and their meanings.

     -u user       Set the owner of the files in the file system to user.  The
                   default owner is the owner of the directory on which the
                   file system is being mounted.  The user may be a user-name,
                   or a numeric value.

     -g group      Set the group of the files in the file system to group.
                   The default group is the group of the directory on which
                   the file system is being mounted.  The group may be a
                   group-name, or a numeric value.

     -s snapshot   The name of the snapshot to mount.  In this usage pathname
                   is the mounted root directory of the base volume containing
                   the snapshot.

DIAGNOSTICS
     The mount_apfs utility exits 0 on success, and >0 if an error occurs.

SEE ALSO
     mount(2), unmount(2), fstab(5), mount(8)

HISTORY
     The mount_apfs utility first appeared in OS X 10.12.

Mac OS X                      September 16, 2015                      Mac OS X