在配置文件中将密码存储为环境变量(而不是纯文本)是否安全?

I work on a few apps in rails, django (and a little bit of php), and one of the things that I started doing in some of them is storing database and other passwords as environment variables rather than plain text in certain config files (or in settings.py, for django apps).I work on a few apps in rails, django (and a li