Usage: sg_verify [--0] [--16] [--bpc=BPC] [--count=COUNT] [--dpo]
                 [--ebytchk=BCH] [--ff] [--group=GN] [--help] [--in=IF]
                 [--lba=LBA] [--ndo=NDO] [--quiet] [--readonly]
                 [--verbose] [--version] [--vrprotect=VRP] DEVICE
  where:
    --0|-0              fill buffer with zeros (don't read stdin)
    --16|-S             use VERIFY(16) (def: use VERIFY(10) )
    --bpc=BPC|-b BPC    max blocks per verify command (def: 128)
    --count=COUNT|-c COUNT    count of blocks to verify (def: 1).
    --dpo|-d            disable page out (cache retention priority)
    --ebytchk=BCH|-E BCH    sets BYTCHK value, either 1, 2 or 3 (def: 0).
                            BCH overrides BYTCHK=1 set by '--ndo='. If
                            BCH is 3 then NDO must be the LBA size
                            (plus protection size if DIF active)
    --ff|-f             fill buffer with 0xff bytes (don't read stdin)
    --group=GN|-g GN    set group number field to GN (def: 0)
    --help|-h           print out usage message
    --in=IF|-i IF       input from file called IF (def: stdin)
                        only active if --ebytchk=BCH given
    --lba=LBA|-l LBA    logical block address to start verify (def: 0)
    --ndo=NDO|-n NDO    NDO is number of bytes placed in data-out buffer.
                        These are fetched from IF (or stdin) and used
                        to verify the device data against. Forces
                        --bpc=COUNT. Sets BYTCHK (byte check) to 1
    --quiet|-q          suppress miscompare report to stderr, still
                        causes an exit status of 14
    --readonly|-r       open DEVICE read-only (def: open it read-write)
    --verbose|-v        increase verbosity
    --version|-V        print version string and exit
    --vrprotect=VRP|-P VRP    set vrprotect field to VRP (def: 0)

Performs one or more SCSI VERIFY(10) or SCSI VERIFY(16) commands. sbc3r34
made the BYTCHK field two bits wide (it was a single bit).