My Rsync backup script (using cygwin)

#!/bin/sh
# Prefix
disk_prefix="/cygdrive/d"

# Backup target
target_dir="/cygdrive/g/backup/"

# List of dir to backup
declare -a dir_list
dir_list=("${disk_prefix}/./Applications"\
          "${disk_prefix}/./dev_workspace"\
          "${disk_prefix}/./xzc")

# Check if target dir is availaible
if [ ! -d "$target_dir" ] ; then
    echo "Destination directory \"$target_dir\" does not exist! Quitting..."
    exit 1
fi
# On screen prompts
echo "####################################"
echo "Target dir is ${target_dir}"
echo "The following ${#dir_list[@]} dir(s) will be synchronized with external disk"
echo ${dir_list[@]}
echo "####################################"
# echo ${dir_list[@]}
for (( i=0 ; i<${#dir_list[@]} ; i++ )) ; do
    echo "# Processing ${dir_list[i]}"
    rsync -rtvR  --modify-window=2 --delete --human-readable --progress "${dir_list[i]}" "${target_dir}"
done