Positional arguments handling on Bash scripts

bash-args.sh

#!/usr/bin/env bash

__iterate_on_args() {
	for a; do echo "arg: $a"; done
}

__iterate_on_glob() {
	#shopt -o nullglob
	for f in *."${1:-sh}"; do
		echo "file: $f"
	done
}

__iterate_on_files() {
	: "${1:?Missing operand}"
	for f; do if [[ -f "$f" ]]; then
		echo "file: '$f'"
	else echo "$0: '$f' is not a valid file" >&2
	fi done
}