/usr/share/zfs/zfs-tests/bin/file_append: invalid option -- '-'
Unrecognized option: --
usage file_append -f filename -e expected_offset [-b blocksize]
         [-n numblocks] [-d use_odirect] [-h help]

Opens a file using O_APPEND and writes numblocks blocksize
blocks to filename.
Checks if expected_offst == lseek(fd, 0, SEEK_CUR)).

    filename:         File to open with O_APPEND and write to.
    expected_offset:  Expected file offset after writing
                      blocksize numblocks to filename
    blocksize:        Size of each block to writei (must be at
                      least >= 512). If using use_odirect (-d)
                      must be a mutltiple of _SC_PAGE_SIZE
    numblocks:        Total number of blocksized blocks to
                      write.
    use_odirect:      Open file using O_DIRECT.
    help:             Print usage information and exit.

    Required parameters:
    filename
    expected_offset

    Default values:
    blocksize   -> 131072 (128 KiB)
    numblocks   -> 8
    use_odirect -> False