#!/bin/bash

var_append() {
	eval "[ \"\$$1\" ] && $1=\"\${$1}$2\"" || true
	eval "$1=\"\${$1}\$3\""
}
var_insert() {
	eval "[ \"\$$1\" ] && $1=\"$2\$$1\"" || true
	eval "$1=\"\$3\$$1\""
}