Bash script to bulk rename subdirectories to lowercase and change spaces for underscore

bulk_dir_rename.sh

#!/bin/bash
# use: "bash bulk_dir_rename.sh path"
source_dir=$1

for found_dir in $source_dir/*;
do
    original_dir_name=$(basename "${found_dir}")
    lowercase_name=${original_dir_name,,}
    no_space_dir=$(echo "$lowercase_name" | sed -e 's/ /_/g')

    if [[ "${found_dir}" != "${source_dir}/${no_space_dir}" ]]; then
        mv "${found_dir}" "${source_dir}/${no_space_dir}"
    fi
done