Convenient backup script to detect my encrypted USB backup disks, mount them and call bontmia

backup.sh

#!/bin/bash

ACTION="${1:-backup}"

# Backup configuration
declare TARGET="backup-perso"
declare MNTPOINT="/mnt/usbdisk"
declare SRC=~

# Device configurations
declare -A DEVICES=(
    ["usb-WD_My_Passport_0748_575831314139335735353037-0:0"]="backup_home_hd"
    ["ata-Samsung_Portable_SSD_T5_S4B5NR0N300922V"]="backup_home_flash"
    ["ata-WDC_WD40NMZW-59GX6S1_WD-WX41D38AXAP4"]="backup_work_hd"
)

declare -a DETECTED_DEVICES

function detect_available_disk() {
    echo "==> Scanning for available backup devices..."

    for device in "${!DEVICES[@]}"; do
        if [ -e "/dev/disk/by-id/$device" ]; then
            DETECTED_DEVICES+=("$device")
        fi
    done

    if (( ${#DETECTED_DEVICES[@]} == 0 )); then
        echo "ERROR: No recognized backup device found!"
        exit 1
    fi
}

function show_config() {
    device=$1
    echo "==========================================="
    echo "    Device:      ${device}"
    echo "    Crypt name:  ${DEVICES[$device]}"
    echo "    Source:      ${SRC}"
    echo "    Destination: ${MNTPOINT}/${device}/${TARGET}"
    echo "==========================================="
}

function mount_usbdisk() {
    device=$1
    echo "==> Opening LUKS container ${DEVICES[$device]}..."
    if ! sudo cryptsetup open --type luks "/dev/disk/by-id/${device}" "${DEVICES[$device]}"; then
        echo "ERROR: Failed to open LUKS container"
        exit 1
    fi

    echo "==> Mounting ${device}..."
    sudo mkdir -p "${MNTPOINT}/${DEVICES[$device]}"
    if ! sudo mount "/dev/mapper/${DEVICES[$device]}" "${MNTPOINT}/${DEVICES[$device]}"; then
        echo "ERROR: Failed to mount device"
        sudo cryptsetup luksClose "${DEVICES[$device]}"
        exit 1
    fi

    echo "==> /dev/mapper/${device} mounted to ${MNTPOINT}/${DEVICES[$device]}"
}

function backup() {
    device=$1
    echo "==> Starting backup with bontmia..."

    if [ ! -d "${MNTPOINT}/${DEVICES[$device]}" ] || ! mountpoint -q "${MNTPOINT}/${DEVICES[$device]}"; then
        echo "ERROR: Mount point ${MNTPOINT}/${DEVICES[$device]} is not mounted"
        exit 1
    fi

    mkdir -p "${MNTPOINT}/${DEVICES[$device]}/$TARGET"
    if bontmia --dest "${MNTPOINT}/${DEVICES[$device]}/$TARGET" \
            --rotation 0minutes0hours7days4weeks6month0years \
            $SRC
    then
        echo "==> Backup completed successfully"
    else
        echo "ERROR: Backup failed"
        exit 1
    fi
}

function umount_usbdisk() {
    device=$1

    echo "==> Unmounting ${device}..."
    sync
    if ! sudo umount "${MNTPOINT}/${DEVICES[$device]}" ; then
        echo "WARNING: Failed to unmount cleanly, forcing..."
        sudo umount -f "${MNTPOINT}/${DEVICES[$device]}" || true
    fi

    echo "==> Closing LUKS container ${DEVICES[$device]}..."
    if ! sudo cryptsetup luksClose "${DEVICES[$device]}"; then
        echo "WARNING: Failed to close LUKS container"
        return 1
    fi

    echo "==> Device safely disconnected"
}

function usage() {
    echo "Usage: $0 [ACTION]"
    echo "Actions:"
    echo "  backup  - Loop on available backup devices, mount, perform backup, unmount (default)"
    echo "  mount   - Mount device only"
    echo "  umount  - Unmount device only"
    echo "  detect  - Show detected device and configuration"
    echo
    echo "Supported devices:"
    for device in "${!DEVICES[@]}"; do
        echo "  - $device (${DEVICES[$device]})"
    done
}

case "$ACTION" in
    "backup")
        detect_available_disk
        for device in "${DETECTED_DEVICES[@]}"; do
            show_config "${device}"
            mount_usbdisk "${device}"
            backup "${device}"
            umount_usbdisk "${device}"
        done
        ;;
    "mount")
        detect_available_disk
        for device in "${DETECTED_DEVICES[@]}"; do
            show_config "${device}"
            mount_usbdisk "${device}"
        done
        ;;
    "umount")
        detect_available_disk
        for device in "${DETECTED_DEVICES[@]}"; do
            show_config "${device}"
            umount_usbdisk "${device}"
        done
        ;;
    "detect")
        detect_available_disk
        for device in "${DETECTED_DEVICES[@]}"; do
            show_config "${device}"
        done
        ;;
    "help"|"-h"|"--help")
        usage
        ;;
    *)
        echo "ERROR: Unknown action '$ACTION'"
        echo
        usage
        exit 1
        ;;
esac