SH Script - Concatenate Strings

    I've built a simple SH script to run rsync to download media from my NAS to a local USB hard drive on a Raspberry Pi (want the hardware to be portable for when I travel for work...). This should have been straight forward but silly string concatenation is messing this up. See in line for where script is messing up:::

    SOURCE_FOLDER="/storage/SHARED/MEDIA"

    echo "Source folder to backup is: " $SOURCE_FOLDER

    TARGET_FOLDER="/var/media/USB2TB"

    echo "Target folder parent folder is: " $TARGET_FOLDER

    CURRENT_SCRIPT_NAME_FQDN=$(readlink -f $0)

    echo "Current script FQDN is: " $CURRENT_SCRIPT_NAME_FQDN

    CURRENT_SCRIPT_NAME_PATH=$(dirname $CURRENT_SCRIPT_NAME_FQDN)

    echo "Current script path is: " $CURRENT_SCRIPT_NAME_PATH

    CURRENT_SCRIPT_FULL_NAME=$(basename $CURRENT_SCRIPT_NAME_FQDN)

    echo "Current script full name is: " $CURRENT_SCRIPT_FULL_NAME

    CURRENT_SCRIPT_NAME="${CURRENT_SCRIPT_FULL_NAME%.*}"

    echo "Current script name is: " $CURRENT_SCRIPT_NAME

    LOG_FILE_TIME=$(date +"%Y%m%d%H%M%S")

    echo "Log file time is: " $LOG_FILE_TIME

    LOG_FILE_EXTENSION=".log"

    echo "Log file extension is: " $LOG_FILE_EXTENSION

    LOG_FILE_DELIMITER="_"

    echo "Log file delimiter is: " $LOG_FILE_DELIMITER

    # ISSUES HERE:

    LOG_FILE_NAME="${CURRENT_SCRIPT_NAME}${LOG_FILE_DELIMITER}${LOG_FILE_TIME}${LOG_FILE_EXTENSION}"

    echo "Log file name is: $LOG_FILE_NAME"

    # This is expected to return "MIRROR-MEDIA_20191002135123.log" but does NOT!

    # AND ISSUES HERE:

    LOG_FILE_FQDN="$CURRENT_SCRIPT_NAME_PATH/$LOG_FILE_NAME"

    echo "Log file FQDN is: " $LOG_FILE_FQDN

    # This is expected to return "/var/media/USB2TB/MIRROR-MEDIA_20191002135123.log" but does NOT!

    # rsync -avzn $SOURCE_FOLDER $TARGET_FOLDER

    # rsync --log-file=$LOG_FILE_FQDN -avz --delete $SOURCE_FOLDER $TARGET_FOLDER

    Works here it seems: