grub smart configuration

#! /bin/bash
#  https://www.gnu.org/software/grub/manual/grub/html_node/Simple-configuration.html


GRUB_DISTRIBUTOR="$(
    lsb_release --id --short 2> /dev/null |
    sed --expression="s|Linux||g"
)"


MULTIPLE_OSES="$(
    if [[ -f "/usr/bin/os-prober" ]] && [[ -n "$(os-prober 2>/dev/null)" ]]; then
        echo x
    fi
)"


GRUB_DISABLE_OS_PROBER="$(
    if [[ -n "${MULTIPLE_OSES}" ]]; then
        echo "false"
    else
        echo "true"
    fi
)"


GRUB_TIMEOUT_STYLE="$(
    if [[ -n "${MULTIPLE_OSES}" ]]; then
        echo "menu"
    else
        echo "hidden"
    fi
)"


GRUB_TIMEOUT="$(
    if [[ -n "${MULTIPLE_OSES}" ]]; then
        echo "20"
    else
        echo "0"
    fi
)"


GRUB_CMDLINE_LINUX_DEFAULT="$(
    if [[ -f "/usr/bin/plymouth" ]]; then
        printf "splash "
    fi

    echo "quiet loglevel=3 systemd.show_status=auto"
)"


GRUB_ENABLE_CRYPTODISK="$(
    if lsblk --fs | grep --quiet "crypto_LUKS"; then
        echo "y"
    else
        echo "n"
    fi
)"


GRUB_GFXMODE=640x480
GRUB_PRELOAD_MODULES="part_gpt part_msdos"

GRUB_SAVEDEFAULT=true
GRUB_DEFAULT=saved
GRUB_DISABLE_RECOVERY=true