public static String extractMavenPropertyName(String propName) {
        Matcher matcher = Pattern.compile(MAVEN_PROPERTY_REGEXP).matcher(propName);
        if (matcher.matches()) {
            return matcher.group(1);
        } else {
            return null;
        }
    }
Extract from a Maven property which is in the form ${name} the name.

@param propName property name to extrat
@return the pure name or null if this is not a property name
src/main/java/io/fabric8/maven/docker/util/EnvUtil.java