/usr/bin/scsi_readcap is in sg3-utils 1.39-1.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 | #!/bin/bash
###################################################################
#
#  Fetch READ CAPACITY information for the given SCSI device(s).
#
#  This script assumes the sg3_utils package is installed.
#
##################################################################
verbose=""
brief=""
long_opt=""
usage()
{
  echo "Usage: scsi_readcap [-b] [-h] [-l] [-v] <device>+"
  echo "  where:"
  echo "    -b, --brief          output brief capacity data"
  echo "    -h, --help           print usage message"
  echo "    -l, --long           send longer SCSI READ CAPACITY (16) cdb"
  echo "    -v, --verbose        more verbose output"
  echo ""
  echo "Use SCSI READ CAPACITY command to fetch the size of each <device>"
}
opt="$1"
while test ! -z "$opt" -a -z "${opt##-*}"; do
  opt=${opt#-}
  case "$opt" in
    b|-brief) brief="-b" ;;
    h|-help) usage ; exit 0 ;;
    l|-long) long_opt="--16" ;;
    v|-verbose) verbose="-v" ;;
    vv) verbose="-vv" ;;
    vvv) verbose="-vvv" ;;
    *) echo "Unknown option: -$opt " ; exit 1 ;;
  esac
  shift
  opt="$1"
done
if [ $# -lt 1 ]
  then
    usage
    exit 1
fi
for i
do
	if [ $brief ] ; then
        	sg_readcap $brief $long_opt $verbose $i 2> /dev/null
	else
		echo "sg_readcap $brief $long_opt $verbose $i"
        	sg_readcap $brief $long_opt $verbose $i
	fi
done
 |