/usr/share/zfs/zfs-tests/bin/idmap_util: invalid option -- '-'
Usage: /usr/share/zfs/zfs-tests/bin/idmap_util [-r] [-c] [-m <idmap1>] [-m <idmap2>] ... [<source>] [<target>]

  -r Recursively do idmapped mount.

  -c Checks if idmapped mount is supported on the <source> by the operating system or not.

  -m <idmap> to specify the idmap info, in the following format:
     <id_type>:<nsid_first>:<hostid_first>:<count>

  <id_type> can be either of 'b', 'u', and 'g'.

The <source> folder will be mounted at <target> with the provided idmap information.
If no <target> is specified, and <source> is a mount point, then <source> will be unmounted and then remounted.