Need some advice on CLI design, I need to provide simple but powerful command line options

I am writing a utility that runs on RHEL5 command line. I need my command line options to be simple but powerful. I looked at the various UNIX utilities to get an idea of how simple command line utilities have to be. Do you guys suggest any documents/links that talk about command line etiquette? I am modelling my utility on top of LVM (that’s all the info I can give for now). I know it’s a software engineering question, but I thought it would be appropriate to post here. Please advise….

Do I need to use an interface when only one class will ever implement it?

Isn’t the whole point of an interface that multiple classes adhere to a set of rules and implementations?

Is there a different usage rationale for abstract classes/interfaces in C++ and Java

According to Herb Sutter one should prefer abstract interfaces (all pure virtual functions) to abstract classes in C++ to decouple the implementation as far as possible. While I personally find this rule very useful, I have recently joined a team with many Java programmers and in the Java code this guideline does not seem to exist. Functions and their implementations are very frequently located in abstract classes.
So did I get Herb Sutter all wrong even for C++ or is there a general difference in the usage of abstract functions in C++ compared to Java. Are abstract classes with implementation code more sensible in Java than in C++ and if yes why ?

Return interface or class

Suppose I have a method

Using a openid in a “closed system”

I would like to publish a website for certain family members only. Simply put, like a mishmash of family photos and videos. I want it to remain private, however.

What do you call an interface with no defining methods used as property setters

In ASP.NET and C# I’ve ran across this before. Your class needs to implement interface ISomething in order for something in the super class to supply something to you.

Why this code create object as interface?

In am reading Spring in Action (3rd edition) and here a snippet from it:

Use cases for “private” interfaces?

I was wondering if there was a valid use case for being able to properly define the specific internal properties and functions of a class in a way similar to how an interface defines the public properties and functions of a class.

Is there an “ask for only what you need” interface principle?

I have grown into using a principle for designing and consuming interfaces that says basically, “ask for only what you need.”

What level of detail to use in an interface members descriptions?

I am extracting interfaces from some classes in .NET, and I am not completely sure about what level of detail of description to use for some of the interface members (properties, methods).