http://www.faqs.org/docs/artu/ch01s06.html

( from Eric Steven Raymond, The Art of Unix Programming )

• Rule of Modularity: Write simple parts connected by clean interfaces.
• Rule of Clarity: Clarity is better than cleverness.
• Rule of Composition: Design programs to be connected with other programs.
• Rule of Separation: Separate policy from mechanism; separate interfaces from engines.
• Rule of Simplicity: Design for simplicity; add complexity only where you must.
• Rule of Parsimony: Write a big program only when it is clear by demonstration that nothing else will do.
• Rule of Transparency: Design for visibility to make inspection and debugging easier.
• Rule of Robustness: Robustness is the child of transparency and simplicity.
• Rule of Representation: Fold knowledge into data, so program logic can be stupid and robust.
• Rule of Least Surprise: In interface design, always do the least surprising thing.
• Rule of Silence: When a program has nothing surprising to say, it should say nothing.
• Rule of Repair: Repair what you can — but when you must fail, fail noisily and as soon as possible.
• Rule of Economy: Programmer time is expensive; conserve it in preference to machine time.
• Rule of Generation: Avoid hand-hacking; write programs to write programs when you can.
• Rule of Optimization: Prototype before polishing. Get it working before you optimize it.
• Rule of Diversity: Distrust all claims for one true way.
• Rule of Extensibility: Design for the future, because it will be here sooner than you think.