Bash quicksort

bash-quicksort.sh

#!/usr/bin/env bash

quicksort() {
	local i m
	quicksort_return=()
	local left=() right=()

	(($#==0)) && return 0
	m=$1
	# echo "Pivot: <$m>"
	shift
	for i; do
		if [[ $i < $m ]]; then
			left+=( $i )
		else
			right+=( $i )
		fi
	done

	# echo "Left: [${left[@]}]"
	# echo "Right: [${right[@]}]"
	quicksort "${left[@]}"
	left=( "${quicksort_return[@]}" )
	quicksort "${right[@]}"
	right=( "${quicksort_return[@]}" )
	quicksort_return=( "${left[@]}" "$m" "${right[@]}" )
	# echo "Returning [${quicksort_return[@]}]"
}

data=(4 9 2 6 3 8 1 5)
echo "Initial data: [${data[@]}]"
quicksort "${data[@]}"
echo "Sorted: [${quicksort_return[@]}]"