#!/usr/bin/env bash

fold() {
	shopt -s checkwinsize
	(
		:
		:
	)
	width="${1:-$COLUMNS}"
	while read -r line; do
		: "${line//	/ }"
		IFS=$'\n' read -d "" -ra words <<<"${line// /$'\n'}"
		ll=0
		for word in "${words[@]}"; do
			wl="${#word}"
			if ((ll + wl > width)); then
				printf '\n'
			else
				((ll += wl))
				printf '%s ' "$word"
			fi
		done
	done
}

fold "$@"