Reusability and NIH

Peter Donis has a nice post discussing a programming challenge given to Knuth and critiqued by McIlroy. Don Knuth, certainly one the premier computer scientists (period) was asked to demonstrate literate programming by solving a simple problem involving finding the n most frequent words in a given text. Doug McIlroy, who’s also well known but not nearly as much as he should be¹, was asked to critique Knuth’s solution. McIlroy’s critique consisted of a 6-line shell script that solved the exact same problem as Knuth’s 10-page Pascal program.

McIlroy’s larger point was about reusability (follow the link to Donis’s post for the details) but what struck me about the story—and made me vaguely uncomfortable because I’m often guilty of this—was how often those of us with the hacker disposition are inclined to jump in and implement a solution to a problem in our $FAVORITE_LANGUAGE rather than use existing functionality as McIlroy did.

It’s amazing how often a simple shell script can solve a problem simply and elegantly. It’s just crazy that we would rather write pages of code rather than simply use a pipeline of a few of the robust and tested Unix utilities. The problem, I think, is that we really love programming and it seems like cheating to solve a problem using a line or two of shell script.

It’s worth remembering that the goal is—most often—solving the problem in the fastest and easiest way. Sometimes that means a simple shell script rather than rolling up our sleeves and cranking out code.