Many applications will have a hierarchy of configuration options. There could be defaults that are built in to a particular release. There might be server-wide (or cluster-wide) values. There might be user-specific values, or perhaps even configuration files that are local to a specific invocation of a program.
In many cases, these configuration parameters will be written in files so that they are easy to change. The common tradition in Linux is to put system-wide configuration in the /etc directory. A user's personal changes would be in their home directory, often named ~username.
How can we support a rich hierarchy of locations for configuration files?
