from:
        http://cburgmer.posterous.com/pip-requirementstxt-and-setuppy

def parse_dependency_links(file_name):
    """
    from:
        http://cburgmer.posterous.com/pip-requirementstxt-and-setuppy
    """
    dependency_links = []
    with open(file_name) as f:
        for line in f:
            if re.match(r'\s*-[ef]\s+', line):
                dependency_links.append(re.sub(r'\s*-[ef]\s+',\
                        '', line))
    return dependency_links