.bashrc lines to stop user from accessing block devices directly

devsdx_protector.sh

# disallow accessing block devices directly
reject_devsdx () {
    # check if being executed at the top-level (e.g. invoked by the user trying to execute a command, but not when doing tab completion)
    if [[ -z "${FUNCNAME[1]}" ]]
    then
        blockdev_path=""
        # check each argument if it is a path that refers to a block device
        for arg in ${BASH_COMMAND}
        do
            # it is safe to use  ${arg} without quotes here since the for loop has split it anyway
            if [[ ${arg} =~ "/dev/" && "$(LC_ALL=C stat --format %F $(echo ${arg} | grep -oE /dev/[^\"\']+))" == "block special file" ]]
            then
                blockdev_path=${arg}
            fi
        done
        if [[ -n "${blockdev_path}" ]]
        then
            aliases="$(find /dev/disk -type l -printf '%p -> ' -exec readlink --canonicalize {} ';' | grep --word-regexp ${blockdev_path})"
            if [[ -n "${aliases}" ]]
            then
                echo "Stop being stupid. Use one of these:"
                echo "${aliases}"
                return 1 # this will inhibit the command execution
            fi
        fi
    fi
}
shopt -s extdebug
trap reject_devsdx DEBUG