#!/bin/sh
set -eu

usage() {
	cat <<-'EOF'
		Usage:
		  password [LENGTH]
		  password -h
	EOF
}

help() {
	cat <<-'EOF'

		Options:
		  -h, --help    show this message

		  LENGTH        the size of the password (default: 99)
	EOF
}

for flag in "$@"; do
	case "$flag" in
		--)
			break
			;;
		--help)
			usage
			help
			exit
			;;
		*)
			;;
	esac
done

while getopts 'h' flag; do
	case "$flag" in
		h)
			usage
			help
			exit
			;;
		*)
			usage >&2
			exit 2
			;;
	esac
done
shift $((OPTIND - 1))


LENGTH="${1-99}"
tr -cd '[:alnum:]' < /dev/random |
	fold -w "$LENGTH" |
	head -n1 |
	tr -d '\n'