bash-best-practics.sh

#!/usr/bin/env bash
set -Eeuo pipefail
trap finally SIGINT SIGTERM ERR EXIT

SCRIPT_DIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
readonly SCRIPT_DIR

function usage() {
	cat <<-EOF
		Usage: $(basename "${BASH_SOURCE[0]}") [-h] [-v] [-p param_value] arg1 [arg2]

		description.

		Options:
		-h, --help     Print this help
		-v, --verbose  Print script debug info
		-p, --param    Some param description

		Arguments:
		arg1     aaaaa
		arg2     bbbbb
	EOF
}

function parse_args() {
	while :; do
		case ${1:-default} in
		-h | --help) usage && exit ;;
		-v | --verbose) set -x ;;
		-p | --param)
			local param="${2}"
			shift
			;;
		-?*)
			printf "\033[31m%s\033[m\n\n" "ERROR: unknown option" >&2
			usage && exit 1
			;;
		*) break ;;
		esac
		shift
	done
	if [[ $# -eq 0 ]]; then
		printf "\033[31m%s\033[m\n\n" "ERROR: missing arguments" >&2
		usage && exit 1
	fi
	readonly PARAM=${param:-}
	readonly ARG1=${1}
	readonly ARG2=${2:-}
}

function finally() {
	trap - SIGINT SIGTERM ERR EXIT
	echo "cleanup done"
}

function main() {
	parse_args "$@"
	echo "$SCRIPT_DIR"
	echo "$ARG1 $ARG2 $PARAM"
}

if [[ "${BASH_SOURCE[0]}" == "${0}" ]]; then
	main "$@"
fi