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The Art of Unix Programming
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Unix Programming - Compactness and Orthogonality - The Value of Detachment

The Value of Detachment

We began this book with a reference to Zen: “a special transmission, outside the scriptures”. This was not mere exoticism for stylistic effect; the core concepts of Unix have always had a spare, Zen-like simplicity that continues to shine through the layers of historical accidents that have accreted around them. This quality is reflected in the cornerstone documents of Unix, like The C Programming Language [Kernighan-Ritchie] and the 1974 CACM paper that introduced Unix to the world; one of the famous quotes from that paper observes “...constraint has encouraged not only economy, but also a certain elegance of design”. That simplicity came from trying to think not about how much a language or operating system could do, but of how little it could do — not by carrying assumptions but by starting from zero (what in Zen is called “beginner's mind” or “empty mind”).

To design for compactness and orthogonality, start from zero. Zen teaches that attachment leads to suffering; experience with software design teaches that attachment to unnoticed assumptions leads to non-orthogonality, noncompact designs, and projects that fail or become maintenance nightmares.

To achieve enlightenment and surcease from suffering, Zen teaches detachment. The Unix tradition teaches the value of detachment from the particular, accidental conditions under which a design problem was posed. Abstract. Simplify. Generalize. Because we write software to solve problems, we cannot completely detach from the problems — but it is well worth the mental effort to see how many preconceptions you can throw away, and whether the design becomes more compact and orthogonal as you do that. Possibilities for code reuse often result.

Jokes about the relationship between Unix and Zen are a live part of the Unix tradition as well.[45] This is not an accident.



[43] In the foundation text on this topic, Refactoring [Fowler], the author comes very close to stating that the principal goal of refactoring is to improve orthogonality. But lacking the concept, he can only approximate this idea from several different directions: eliminating code duplication and various other “bad smells” many of which are some sort of orthogonality violation.

[44] An archetypal example of bad caching is the rehash directive in csh(1); type man 1 csh for details. See the section called “Caching Operation Results” for another example.

[45] For a recent example of Unix/Zen crossover, see AppendixD.


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The Art of Unix Programming
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