Store the files in current directory with respect to their extensions if they have

storebyext.sh

search_dir='.'
for entry in "$search_dir"/*; do
	# entry = la/bas/truc.zip
	filename=$(basename "$entry")
	# filename = truc.zip
	extension=$([[ "$filename" = *.* ]] && echo "${filename##*.}" || echo '')
	# extension = zip
	re_nbr='^[0-9]+$'
	if ! [[ $extension =~ $re_nbr ]] && ! [[ -z "$extension" ]] ; then
		if ! [[ -d "$extension" ]] ; then
			echo "$extension"
			mkdir "$extension"
		fi
		# filename="${filename%(.*)}"
		mv "$entry" "$extension"/
	fi
done